WO1996015780A1 - Compositions and methods for preventing and treating allograft rejection - Google Patents

Abstract

Compositions and methods are provided for the prevention and treatment of allograft rejection. Compositions are provided which comprise an antisense oligonucleotide targeted to a nucleic acid sequence encoding intercellular adhesion molecule-1, vascular cell adhesion molecule-1, or endothelial leukocyte adhesion molecule-1 in combination with an immunosuppressive agent. Methods of preventing or treating allograft rejection by treating an allograft recipient with such a composition are provided. Methods for preventing allograft rejection comprising pretreatment of the graft are also provided.

Description

COMPOSITIONS AND METHODS FOR PREVENTING AND

TREATING ALLOGRAFT REJECTION

FIELD OF THE INVENTION

This invention relates to compositions and methods for preventing and treating allograft rejection. In particular, compositions comprising an antisense oligonucleotide in combination with an immunosuppressive agent are provided. The antisense oligonucleotide is targeted to nucleic acids encoding intercellular adhesion molecule-1 (ICAM-1), endothelial leukocyte adhesion molecule-1 (ELAM-1, also known as E-selectin) or vascular cell adhesion molecule-1 (VCAM-1). The immunosuppressive agent is a monoclonal antibody, antisense oligonucleotide or conventional immunosuppressive agent such as brequinar, rapamycin or antilymphocyte serum. These compositions have been found to extend allograft survival times and induce donor-specific transplant tolerance. These compositions are useful for preventing and treating allograft rejection and for inducing tolerance to specific allergens or antigens. BACKGROUND OF THE INVENTION

Inflammation is a localized protective response elicited by tissues in response to injury, infection, or tissue destruction resulting in the destruction of the infectious or injurious agent and isolation of the injured tissue. A typical inflammatory response proceeds as follows: recognition of an antigen as foreign or recognition of tissue damage; synthesis and release of soluble inflammatory mediators; recruitment of inflammatory cells to the site of infection or tissue damage; destruction and removal of the invading organism or damaged tissue; and deactivation of the system once the invading organism or damage has been resolved.

Cell -cell interactions are involved in the activation of the immune response at each of the stages described above. One of the earliest detectable events in a normal inflammatory response is adhesion of leukocytes to the vascular endothelium, followed by migration of leukocytes out of the vasculature to the site of infection or injury. The adhesion of these leukocytes, or white blood cells, to vascular endothelium is an obligate step in the migration out of the vasculature. Harlan, J.M., Blood 1985, 65, 513-525.

The adhesion of white blood cells to vascular endothelium and other cell types is mediated by interactions between specific proteins, termed "adhesion molecules", located on the plasma membrane of both white blood cells and vascular endothelium. The interaction between adhesion molecules is similar to classical receptor ligand interactions with the exception that the ligand is fixed to the surface of a cell instead of being soluble. The adherence of white blood cells to vascular endothelium appears to be mediated in part if not in toto by the five cell adhesion molecules: intercellular adhesion molecule-1 (ICAM-1); ICAM-2; endothelial leukocyte adhesion molecule-1 (ELAM-1, also called E-selectin); vascular cell adhesion molecule-1 (VCAM-1); and granule membrane protein-140 (GMP-140). Expression on the cell surface of ICAM-1, ICAM-2, ELAM-1, VCAM-1 and GMP-140 adhesion molecules is induced by inflammatory stimuli. The expression of ELAM-1 and VCAM-1 on endothelial cells is induced by cytokines such as interleukin-1ß and tumor necrosis factor, but not gamma-interferon. ICAM-1 expression on endothelial cells is induced by the cytokines, interleukin-1 tumor necrosis factor and gamma-interferon.

In organ transplantation, the reaction of host immune cells with transplant cells is mediated by adhesive cell membrane receptors. An essential step in the activation of T lymphocytes is their interaction with endothelial cells of the graft. Binding of T lymphocytes to the endothelial cells requires intercellular adhesion molecules. It is believed that the induction of ICAM-1 influences the leukocyte response in transplanted tissue. ICAM-1 has been shown to be expressed in rejecting kidney and liver allografts; Faull and Russ, Transplantation 1989, 48, 226-230; Adams et al., Lancet 1989, 2(8672), 1122-1125. ICAM-1 is also expressed on the endothelial-rich pancreatic islet complex; Zeng et al., Transplantation 1994, 58, 681-689. Other adhesion molecules, including VCAM-1 and ELAM-1, are also known to be involved in interactions between the transplanted tissue and the immune system.

It is believed that compositions comprising inhibitors of ICAM-1, VCAM-1 and ELAM-1 expression could provide a novel therapeutic class of anti-rejection agents. The use of neutralizing monoclonal antibodies against ICAM-1 in animal models provides evidence that such inhibitors, if identified, would have therapeutic benefit for renal allografts (Cosimi et al., J. Immunol . 1990, 144, 4604-4612), cardiac allografts (Isobe et al., Science 1992, 255, 1125-1127) and pancreatic islet allografts and xenografts (Zeng et al., Transplantation 1994, 58, 681-689). Experiments in monkeys have been performed to examine the effectiveness of monoclonal antibodies to ICAM-1 in blocking rejection of kidney allografts. Cosimi et al., J. Immunol . 1990, 144, 4604-4612. As in humans, ICAM-1 molecules are expressed on vascular endothelium in normal kidney. During rejection, ICAM-1 expression increased on endothelial and tubular cells and on leukocytes; this increase correlated with massive infiltration of grafts. Treatment with monoclonal antibody to ICAM-1 decreased cellular infiltration and allowed the necessary cyclosporine A dosage to be reduced. Clinical trials conducted in high-risk kidney allograft patients showed that treatment with mouse anti-ICAM-1 monoclonal antibody in a 14 -day postoperative period in addition to the triple drug therapy (cyclosporine A, azathioprine and corticosteroids) improved one-year allograft survival from 56% to 78%. Haug et al., Transplantation 1993, 55, 766-773. However, the majority of patients developed human anti-mouse antibodies within the first two weeks following completion of monoclonal treatment.

Current agents which affect intercellular adhesion molecules include synthetic peptides, monoclonal antibodies, and soluble forms of the adhesion molecules. To date, synthetic peptides which block the interactions with VCAM-1 or ELAM-1 have not been identified. Monoclonal antibodies may prove to be useful for the treatment of allograft rejection due to expression of ICAM-1, VCAM-1 and ELAM-1. The role of ICAM-1 and LFA-1 molecules in graft rejection has been previously demonstrated by treatment of heart allograft recipient mice with monoclonal antibodies to ICAM-1 and LFA-1. This combined treatment induced long-term allograft survival and donor-specific transplantation tolerance. Isobe et al., Science 1992, 255, 1125-1127. However, with chronic treatment, the host animal develops an immune response against the monoclonal antibodies thereby limiting their usefulness in long-term therapy. Soluble forms of the cell adhesion molecules suffer from many of the same limitations as monoclonal antibodies in addition to the expense of their production and their low binding affinity. Thus, there is a long felt need for compositions which effectively inhibit allograft rejection.

PCT/US90/02357 (Hession et al.) discloses DNA sequences encoding Endothelial Adhesion Molecules (ELAMs), including ELAM-1 and VCAM-1 and VCAM-1b. A number of uses for these DNA sequences are provided, including (1) production of monoclonal antibody preparations that are reactive for these molecules which may be used as therapeutic agents to inhibit leukocyte binding to endothelial cells; (2) production of ELAM peptides to bind to the ELAM ligand on leukocytes which, in turn, may bind to ELAM on endothelial cells, inhibiting leukocyte binding to endothelial cells; (3) use of molecules binding to ELAMS (such as anti-ELAM antibodies, or markers such as the ligand or fragments of it) to detect inflammation; and (4) use of ELAM and ELAM ligand DNA sequences to produce nucleic acid molecules which intervene in ELAM or ELAM ligand expression at the translational level using antisense nucleic acid and ribozymes to block translation of a specific mRNA either by masking mRNA with antisense nucleic acid or cleaving it with a ribozyme. It is disclosed that coding regions are the targets of choice. For VCAM-1, AUG is believed to be most likely; a 15-mer hybridizing to the AUG site is specifically disclosed in Example 17 of PCT/US90/02357.

SUMMARY OF THE INVENTION

In accordance with the present invention, compositions for treating allograft rejection are provided. These compositions comprise an antisense oligonucleotide which is targeted to a nucleic acid sequence encoding ICAM-1, ELAM-1 or

VCAM-1 in combination with an immunosuppressive agent.

Also in accordance with the present invention, methods of preventing or treating allograft rejection are provided which comprise treating an allograft recipient with an antisense oligonucleotide which is targeted to a nucleic acid sequence encoding ICAM-1, ELAM-1 or VCAM-1, in combination with an immunosuppressive agent.

Further in accordance with the present invention, methods of preventing rejection of an allograft are provided which comprise treatment of the graft prior to transplantation.

DETAILED DESCRIPTION OF THE INVENTION

Recognition of an antigen as foreign is the initial step in the inflammatory response to injury, infection or tissue destruction. Allograft rejection also begins with the recognition of foreign antigens. The acute infiltration of neutrophils into the site of inflammation appears to be due to increased expression of GMP-140, ELAM-1 and ICAM-1 on the surface of endothelial cells. The appearance of lymphocytes and monocytes during the later stages of an inflammatory reaction appear to be mediated by VCAM-1 and ICAM-1. ELAM-1 and GMP-140 are transiently expressed on vascular endothelial cells, while VCAM-1 and ICAM-1 are chronically expressed.

ICAM-1 is a member of the immunoglobulin supergene family, containing 5 immunoglobulin-like domains at the amino terminus, followed by a transmembrane domain and a cytoplasmic domain. Human ICAM-1 is encoded by a 3.3-kb mRNA resulting in the synthesis of a 55,219 dalton protein. The mRNA sequence of human ICAM-1 (SEQ ID NO: 97) was described by Staunton et al., Cell 1988, 52, 925-933. The mature glycosylated protein has an apparent molecular mass of 90 kDa as determined by SDS-polyacrylamide gel electrophoresis .

ICAM-1 exhibits a broad tissue and cell distribution, and may be found on white blood cells, endothelial cells, fibroblast, keratinocytes and other epithelial cells. The expression of ICAM-1 can be regulated on vascular endothelial cells, fibroblasts, keratinocytes, astrocytes and several cell lines by treatment with bacterial lipopolysaccharide and cytokines such as interleukin-1, tumor necrosis factor, gamma-interferon, and lymphotoxin. See, e . g . , Frohman et al., J. Neuroimmunol . 1989, 23, 117-124. Increased expression of ICAM- 1 molecules correlates with increased leukocyte infiltration followed by the rejection of organ allografts in both humans and mice. Nickoloff et al., J. Immunol. 1993, 150, 2148-2159.

ELAM-1 is a 115 -kDa membrane glycoprotein which is a member of the selectin family of membrane glycoproteins. The mRNA sequence of human ELAM-1 (SEQ ID NO: 98) was described by Bevilacqua et al., Science 1989, 243, 1160-1165. The amino terminal region of ELAM- l contains sequences with homologies to members of lectin-like proteins, followed by a domain similar to epidermal growth factor, followed by six tandem 60-amino acid repeats similar to those found in complement receptors 1 and 2. These features are also shared by GMP-140 and MEL-14 antigen, a lymphocyte homing antigen. ELAM-1 is encoded for by a 3.9-kb mRNA. The 3'-untranslated region of ELAM-1 mRNA contains several ATTTA sequence motifs which are responsible for the rapid turnover of cellular mRNA consistent with the transient nature of ELAM-1 expression.

ELAM-1 exhibits a limited cellular distribution in that it has only been identified on vascular endothelial cells. Like ICAM-1, ELAM-1 is inducible by a number of cytokines including tumor necrosis factor, interleukin-1 and lymphotoxin and bacterial lipopolysaccharide. In contrast to ICAM-1, ELAM-1 is not induced by gamma-interferon. Bevilacqua et al., Proc . Na tl . Acad . Sci . USA 1987, 84, 9238-9242; Wellicome et al., J. Immunol . 1990, 144, 2558-2565. The kinetics of ELAM-1 mRNA induction and disappearance in human umbilical vein endothelial cells precedes the appearance and disappearance of ELAM-1 on the cell surface.

VCAM-1 is a 110 -kDa membrane glycoprotein encoded by a 3.2-kb mRNA. The sequence of human VCAM-1 mRNA (SEQ ID NO: 99) was described by Osborn et al., Cell 1989, 59, 1203-1211. VCAM-1 appears to be encoded by a single-copy gene which can undergo alternative splicing to yield products with either six or seven immunoglobulin domains. The receptor for VCAM-1 is proposed to be CD29 (VLA-4) as demonstrated by the ability of monoclonal antibodies to CD29 to block adherence of Ramos cells to VCAM-1. VCAM-1 is expressed primarily on vascular endothelial cells. Like ICAM-1 and ELAM-1, expression of VCAM-1 on vascular endothelium is regulated by treatment with cytokines. Rice and Bevilacqua, Science 1989, 246, 1303-1306; Rice et al., J. Exp . Med. 1990, 171, 1369-1374.

The present invention employs oligonucleotides targeted to nucleic acid sequences encoding ICAM-1, VCAM-1 or ELAM-1. This relationship between an oligonucleotide and the nucleic acid sequence to which it is targeted is commonly referred to as "antisense." "Targeting" an oligonucleotide to a chosen nucleic acid target, in the context of this invention, is a multistep process. The process usually begins with identifying a nucleic acid sequence whose function is to be modulated. This may be, as examples, a cellular gene (or mRNA made from the gene) whose expression is associated with a particular disease state, or a foreign nucleic acid from an infectious agent. In the present invention, the target is a nucleic acid sequence encoding ICAM-1, VCAM-1 or ELAM-1; in other words, the gene encoding ICAM-1, VCAM-1 or ELAM-1, or mRNA expressed from the gene encoding ICAM-1, VCAM-1 or ELAM-1. The targeting process also includes determination of a site or sites within the nucleic acid sequence for the oligonucleotide interaction to occur such that the desired effect, i.e., modulation of gene expression, will result. Once the target site or sites have been identified, oligonucleotides are chosen which are sufficiently complementary to the target, i.e., hybridize sufficiently well and with sufficient specificity, to give the desired modulation.

In the context of this invention "modulation" means either inhibition or stimulation. Inhibition of target gene expression is presently the preferred form of modulation. This modulation can be measured in ways which are routine in the art, for example by Northern blot assay of mRNA expression or Western blot assay of protein expression as taught in the examples of the instant application. Effects on allograft survival and graft rejection can also be measured, as taught in the examples of the instant application. "Hybridization", in the context of this invention, means hydrogen bonding, also known as Watson-Crick base pairing, between complementary bases, usually on opposite nucleic acid strands or two regions of a nucleic acid strand. Guanine and cytosine are examples of complementary bases which are known to form three hydrogen bonds between them. Adenine and thymine are examples of complementary bases which form two hydrogen bonds between them. "Specifically hybridizable" and "complementary" are terms which are used to indicate a sufficient degree of complementarity such that stable and specific binding occurs between the DNA or

RNA target and the oligonucleotide. It is understood that an oligonucleotide need not be 100% complementary to its target nucleic acid sequence to be specifically hybridizable. An oligonucleotide is specifically hybridizable when binding of the oligonucleotide to the target interferes with the normal function of the target molecule to cause a loss of utility, and there is a sufficient degree of complementarity to avoid nonspecific binding of the oligonucleotide to non- target sequences under conditions in which specific binding is desired, i.e., under physiological conditions in the case of in vivo assays or therapeutic treatment or, in the case of in vi tro assays, under conditions in which the assays are conducted. In preferred embodiments of this invention, oligonucleotides are provided which are targeted to mRNA encoding ICAM-1, VCAM-1 or ELAM-1. In accordance with this invention, persons of ordinary skill in the art will understand that mRNA includes not only the coding region which carries the information to encode a protein using the three letter genetic code, but also associated ribonucleotides which form a region known to such persons as the 5'-untranslated region, the 3'-untranslated region, the 5' cap region, intron regions and intron/exon or splice junction ribonucleotides. Thus, oligonucleotides may be formulated in accordance with this invention which are targeted wholly or in part to these associated ribonucleotides as well as to the coding ribonucleotides. The functions of messenger RNA to be interfered with include all vital functions such as translocation of the RNA to the site for protein translation, actual translation of protein from the RNA, splicing or maturation of the RNA and possibly even independent catalytic activity which may be engaged in by the RNA. The overall effect of such interference with the RNA function is to cause interference with ICAM-1, VCAM-1 or ELAM-1 protein expression.

In the context of this invention, the term

"oligonucleotide" refers to an oligomer or polymer of nucleotide or nucleoside monomers consisting of naturally occurring bases, sugars and intersugar (backbone) linkages. The term "oligonucleotide" also includes oligomers or polymers comprising non-naturally occurring monomers, or portions thereof, which function similarly. Such modified or substituted oligonucleotides are often preferred over native forms because of properties such as, for example, enhanced cellular uptake, increased stability in the presence of nucleases, or enhanced target affinity. A number of nucleotide and nucleoside modifications have been shown to make the oligonucleotide into which they are incorporated more resistant to nuclease digestion than the native oligodeoxynucleotide . Nuclease resistance is routinely measured by incubating oligonucleotides with cellular extracts or isolated nuclease solutions and measuring the extent of intact oligonucleotide remaining over time, usually by gel electrophoresis . Oligonucleotides which have been modified to enhance their nuclease resistance survive intact for a longer time than unmodified oligonucleotides. A number of modifications have also been shown to increase binding (affinity) of the oligonucleotide to its target. Affinity of an oligonucleotide for its target (in this case, a nucleic acid sequence encoding ICAM-1, ELAM-1 or VCAM-1) is routinely determined by measuring the Tm of an oligonucleotide/target pair, which is the temperature at which the oligonucleotide and target dissociate. Dissociation is detected spectrophotometrically. The higher the Tm, the greater the affinity of the oligonucleotide for the target. In some cases, oligonucleotide modifications which enhance target binding affinity are also, independently, able to enhance nuclease resistance.

Specific examples of some preferred oligonucleotides envisioned for this invention may contain phosphorothioates, phosphotriesters, methyl phosphonates, short chain alkyl or cycloalkyl intersugar linkages or short chain heteroatomic or heterocyclic intersugar ("backbone") linkages. Most preferred are phosphorothioates and those with CH₂-NH-O-CH₂, CH₂-N(CH₃)-O-CH₂, CH₂-O-N(CH₃)-CH₂, CH₂-N(CH₃)-N(CH₃)-CH₂ and O-N(CH₃)-CH₂-CH₂ backbones (where phosphodiester is O-P-O-CH₂). Also preferred are oligonucleotides having morpholino backbone structures. Summerton, J.E. and Weller, D.D., U.S. Patent No: 5,034,506. In other preferred embodiments, such as the protein-nucleic acid or peptide-nucleic acid (PNA) backbone, the phosphodiester backbone of the oligonucleotide may be replaced with a polyamide backbone, the bases being bound directly or indirectly to the aza nitrogen atoms of the polyamide backbone. P.E. Nielsen, M. Egholm, R.H. Berg, O. Buchardt, Science 1991, 254, 1497. Other preferred oligonucleotides may contain alkyl and halogen-substituted sugar moieties comprising one of the following at the 2' position: OH, SH, SCH₃, F, OCN, OCH₃OCH₃, OCH₃O(CH₂)_nCH₃, O(CH₂)_nNH₂ or O(CH₂)_nCH₃ where n is from 1 to about 10; C₁ to C₁₀ lower alkyl, substituted lower alkyl, alkaryl or aralkyl; Cl; Br; CN; CF₃; OCF₃; O-, S-, or N-alkyl; O-, S-, or N-alkenyl; SOCH₃; SO₂CH₃; ONO₂; NO₂; N₃; NH₂; heterocycloalkyl; heterocycloalkaryl; aminoalkylamino; polyalkylamino; substituted silyl; an RNA cleaving group; a cholesteryl group; a reporter group; an intercalator; a group for improving the pharmacokinetic properties of an oligonucleotide; or a group for improving the pharmacodynamic properties of an oligonucleotide and other substituents having similar properties. Oligonucleotides may also have sugar mimetics such as cyclobutyls in place of the pentofuranosyl group. Other preferred embodiments may include at least one modified base form or "universal base" such as inosine.

The oligonucleotides in accordance with this invention preferably are from about 8 to about 50 nucleotides in length. In the context of this invention it is understood that this encompasses non-naturally occurring oligomers as hereinbefore described, having 8 to 50 monomers.

The oligonucleotides used in accordance with this invention may be conveniently and routinely made through the well-known technique of solid phase synthesis. Equipment for such synthesis is sold by several vendors including Applied Biosystems. Any other means for such synthesis may also be employed; the actual synthesis of the oligonucleotides is well within the talents of the routineer. It is also well known to use similar techniques to prepare other oligonucleotides such as the phosphorothioates and alkylated derivatives. It is also well known to use similar techniques and commercially available modified amidites and controlled-pore glass (CPG) products such as those available from Glen Research, Sterling VA, to synthesize modified oligonucleotides such as cholesterol-modified oligonucleotides.

For prophylactics and therapeutics, methods of preventing and treating allograft rejection are provided. The formulation of therapeutic compositions and their subsequent administration is believed to be within the skill in the art. In accordance with some embodiments of this invention, an allograft recipient is treated by administering compositions comprising an antisense oligonucleotide targeted to ICAM-1, VCAM-1 or ELAM-1 in combination with an immunosuppressive agent. In the context of the present invention, "in combination" means that the oligonucleotide and immunosuppressive agent are administered in the same course of treatment and may be administered separately, simultaneously or in a mixture, i.e., a single composition or formulation containing both oligonucleotide and immunosuppressive agent. Examples of immunosuppressive agents include conventional immunosuppressive agents, of which brequinar, rapamycin, and anti- lymphocyte serum are preferred, and monoclonal antibodies, of which those directed to LFA-1 or ICAM-1 are preferred. The immunosuppressive agent may also be an antisense oligonucleotide. Preferred among these are oligonucleotides targeted to B7-2 or LFA-1, or oligonucleotides targeted to ICAM-1, VCAM-1 or ELAM-1.

Oligonucleotides and/or immunosuppressive agents, or combinations of the two, may be formulated in a pharmaceutical composition, which may include carriers, thickeners, diluents, buffers, preservatives, surface active agents, liposomes or lipid formulations and the like in addition to the oligonucleotide. Pharmaceutical compositions may also include one or more active ingredients such as antimicrobial agents, anti-inflammatory agents, anesthetics, and the like. Formulations for parenteral administration may include sterile aqueous solutions which may also contain buffers, liposomes, diluents and other suitable additives.

The pharmaceutical composition may be administered in a number of ways depending on whether local or systemic treatment is desired, and on the area to be treated. Administration may be topical (including ophthalmic, vaginal, rectal, intranasal), oral, by inhalation, or parenteral, for example by intravenous drip, subcutaneous, intraperitoneal or intramuscular injection. In the present invention, intraperitoneal injection, oral gavage or intravenous infusion by osmotic pump are preferred modes of administration.

Dosing is dependent on severity and responsiveness of the condition to be treated, with course of treatment lasting from several days to several months or until a cure is effected or a diminution of disease state is achieved. Optimal dosing schedules can be calculated from measurements of drug accumulation in the body. Persons of ordinary skill can easily determine optimum dosages, dosing methodologies and repetition rates. Optimum dosages may vary depending on the relative potency of individual compositions, and can generally be estimated based on EC50's in in vi tro and animal studies. In general, dosage is from 0.001 μg to 100 g and may be administered once or several times daily, weekly, monthly or yearly, or even every 2 to 20 years.

For prevention of allograft rejection, the allograft may be treated prior to transplantation. Perfusion of the allograft is a preferred form of treatment; ex vivo perfusion is more preferred. Methods of organ perfusion are well known in the art. In general, harvested tissues or organs (preferably heart, kidney or pancreas) are perfused with the compositions of the invention in a pharmacologically acceptable carrier such as, for example, lactated Ringer's solution, University of Wisconsin (UW) solution, Euro-Collins solution or Sachs solution. Simple flushing of the organ or pulsatile perfusion may be used. Perfusion time is generally dependent on the length of ex vivo viability of the organ being transplanted; these viability times vary from organ to organ and are known in the art. Hearts and livers, for example, are generally transplanted within 4 to 6 hours of harvesting, whereas other organs may have longer ischemic viability. Kidneys, for example, may be transplanted up to 48 hr or even 72 hr after harvesting. Dosage may range from 0.001 μg to 500 g each of oligonucleotide and immunosuppressive agent. Pancreatic islet cell allografts are now being used in place of whole pancreas transplants because of the reduced likelihood of rejection. Islet cell transplants are effective in allowing diabetic patients to become independent of insulin injections. Hering et al., Cell Transplant 1993, 2, 269-282. For pancreatic islet allografts, treatment of the isolated islets ex vivo may be preferred. Zeng et al., Transplantation 1994, 58,681-689. Dosage may range from 0.001 μg to 500 g each of oligonucleotide and immunosuppressive agent.

Prophylactic treatment of the allograft recipient with oligonucleotide and/or immunosuppressive agent may also be preferred for prevention of allograft rejection. In this case dosages are expected to be from 0.0001 μg to 100 g each of oligonucleotide and immunosuppressive agent.

Several preferred embodiments of this invention are exemplified in accordance with the following nonlimiting examples. Persons of ordinary skill in the art will appreciate that the present invention is not so limited, however, and that it is generally applicable.

EXAMPLES

Example 1 Synthesis and characterization of oligonucleotides

Unmodified DNA oligonucleotides were synthesized on an automated DNA synthesizer (Applied Biosystems model 380B) using standard phosphoramidite chemistry with oxidation by iodine. β-cyanoethyldiisopropyl-phosphoramidites were purchased from Applied Biosystems (Foster City, CA). For phosphorothioate oligonucleotides, the standard oxidation bottle was replaced by a 0.2 M solution of 3H-1,2-benzodithiole-3-one 1,1-dioxide in acetonitrile for the stepwise thiation of the phosphite linkages. The thiation cycle wait step was increased to 68 seconds and was followed by the capping step.

After cleavage from the controlled pore glass column

(Applied Biosystems) and deblocking in concentrated ammonium hydroxide at 55°C for 18 hours, the oligonucleotides were purified by precipitation twice out of 0.5 M NaCl with 2.5 volumes ethanol. Analytical gel electrophoresis was accomplished in 20% acrylamide, 8 M urea, 45 mM Tris-borate buffer, pH 7.0. Oligodeoxynucleotides and phosphorothioate oligonucleotides were judged from electrophoresis to be greater than 80% full length material.

The relative amounts of phosphorothioate and phosphodiester linkages obtained by this synthesis were periodically checked by ³¹P NMR spectroscopy. The spectra were obtained at ambient temperature using deuterium oxide or dimethyl sulfoxide-d₆ as solvent. Phosphorothioate samples typically contained less than one percent of phosphodiester linkages.

Secondary evaluation was performed with oligonucleotides purified by trityl-on HPLC on a PRP-1 column

(Hamilton Co., Reno, Nevada) using a gradient of acetonitrile in 50 mM triethylammonium acetate, pH 7.0 (4% to 32% in 30 minutes, flow rate = 1.5 ml/min). Appropriate fractions were pooled, evaporated and treated with 5% acetic acid at ambient temperature for 15 minutes. The solution was extracted with an equal volume of ethyl acetate, neutralized with ammonium hydroxide, frozen and lyophilized. HPLC-purified oligonucleotides were not significantly different in potency from precipitated oligonucleotides, as judged by the ELISA assay for ICAM-1 expression.

Example 2 Quantitation of ICAM-1, VCAM-1 and ELAM-1 expression by ELISA

Expression of ICAM-1, VCAM-1 and ELAM- 1 on the surface of cells was quantitated using specific monoclonal antibodies in an ELISA. Cells were grown to confluence in 96-well microtiter plates. The cells were stimulated with either interleukin-1 or tumor necrosis factor for 4 to 8 hours to quantitate ELAM-1 and 8 to 24 hours to quantitate ICAM-1 and VCAM-1. Following the appropriate incubation time with the cytokine, the cells were gently washed three times with a buffered isotonic solution containing calcium and magnesium such as Dulbecco's phosphate buffered saline (D-PBS). The cells were then directly fixed on the microtiter plate with 1 to 2% paraformaldehyde diluted in D-PBS for 20 minutes at 25°C. The cells were washed again with D-PBS three times. Nonspecific binding sites on the microtiter plate were blocked with 2% bovine serum albumin in D-PBS for 1 hour at 37°C. Cells were incubated with the appropriate monoclonal antibody diluted in blocking solution for 1 hour at 37°C. Unbound antibody was removed by washing the cells three times with D-PBS. Antibody bound to the cells was detected by incubation with a 1:1000 dilution of biotinylated goat anti-mouse IgG (Bethesda Research Laboratories, Gaithersberg, MD) in blocking solution for 1 hour at 37°C. Cells were washed three times with D-PBS and then incubated with a 1:1000 dilution of streptavidin conjugated to ß-galactosidase (Bethesda Research Laboratories) for 1 hour at 37°C. The cells were washed three times with D-PBS for 5 minutes each. The amount of ß-galactosidase bound to the specific monoclonal antibody was determined by developing the plate in a solution of 3.3 mM chlorophenolred-ß-D-galactopyranoside, 50 mM sodium phosphate, 1.5 mM MgCl₂; pH=7.2 for 2 to 15 minutes at 37°C. The concentration of the product was determined by measuring the absorbance at 575 nm in an ELISA microtiter plate reader.

Induction of ICAM-1 was observed following stimulation with either interleukin-1ß or tumor necrosis factor α in several human cell lines. Cells were stimulated with increasing concentrations of interleukin- 1 or tumor necrosis factor for 15 hours and processed as described above. ICAM-1 expression was determined by incubation with a 1:1000 dilution of the monoclonal antibody 84H10 (Amac Inc., Westbrook, ME). The cell lines used were passage 4 human umbilical vein endothelial cells (HUVEC), a human epidermal carcinoma cell line (A431), a human melanoma cell line (SK-MEL-2) and a human lung carcinoma cell line (A549). ICAM-1 was induced on all the cell lines; however, tumor necrosis factor was more effective than interleukin-1 in induction of ICAM-1 expression on the cell surface.

Screening antisense oligonucleotides for inhibition of ICAM-1, VCAM-1 or ELAM-1 expression was performed as described above with the exception of pretreatment of cells with the oligonucleotides prior to challenge with the cytokines. Human umbilical vein endothelial cells (HUVEC) were treated with increasing concentration of oligonucleotide diluted in Opti MEM (GIBCO, Grand Island, NY) containing 8 μM N-[1-(2,3-dioleyloxy) propyl]-N,N,N-trimethylammonium chloride (DOTMA) for 4 hours at 37°C to enhance uptake of the oligonucleotides. The medium was removed and replaced with endothelial growth medium (EGM-UV; Clonetics, San Diego, CA) containing the indicated concentration of oligonucleotide for an additional 4 hours. Interleukin-1β was added to the cells at a concentration of 5 units/ml and incubated for 14 hours at 37°C. The cells were quantitated for ICAM-1 expression using a 1:1000 dilution of the monoclonal antibody 84H10 as described above. The oligonucleotides used were:

COMPOUND 1 - (ISIS 1558) a phosphodiester oligonucleotide targeted to position 64-80 of the mRNA covering the AUG initiation of translation codon having the sequence

5' -TGGGAGCCATAGCGAGGC-3' (SEQ ID NO: 1).

COMPOUND 2 - (ISIS 1570) a phosphorothioate oligonucleotide corresponding to the same sequence as COMPOUND 1.

COMPOUND 3 - a phosphorothioate oligonucleotide complementary to COMPOUND 1 and COMPOUND 2 exhibiting the sequence

5' -GCCTCGCTATGGCTCCCA-3' (SEQ ID NO: 81).

COMPOUND 4 - (ISIS 1572) a phosphorothioate oligonucleotide targeted to positions 2190-2210 of the mRNA in the 3' untranslated region containing the sequence

5' -GACACTCAATAAATAGCTGGT-3' (SEQ ID NO: 3). COMPOUND 5 - (ISIS 1821) a phosphorothioate oligonucleotide targeted to human 5-lipoxygenase mRNA used as a control containing the sequence

5' -CATGGCGCGGGCCGCGGG-3' (SEQ ID NO: 82).

The phosphodiester oligonucleotide targeting the AUG initiation of translation region of the human ICAM-1 mRNA

(COMPOUND 1) did not inhibit expression of ICAM-1; however, the corresponding phosphorothioate oligonucleotide (COMPOUND 2) inhibited ICAM-1 expression by 70% at a concentration of 0.1 μM and 90% at 1 μM concentration. The increased potency of the phosphorothioate oligonucleotide over the phosphodiester is due to increased stability. The sense strand to COMPOUND 2,

COMPOUND 3, inhibited ICAM-1 expression by 25% at 10 μM. If COMPOUND 2 was prehybridized to COMPOUND 3 prior to addition to the cells, the effects of COMPOUND 2 on ICAM-1 expression were attenuated suggesting that the activity of COMPOUND 2 was due to antisense oligonucleotide effect, requiring hybridization to the mRNA. The antisense oligonucleotide directed against 3' untranslated sequences (COMPOUND 4) inhibited ICAM-1 expression by 62% at a concentration of 1 μM. The control oligonucleotide, targeting human 5-lipoxygenase (COMPOUND 5), reduced ICAM-1 expression by 20%. These data demonstrate that oligonucleotides are capable of inhibiting ICAM-1 expression on human umbilical vein endothelial cells and suggest that the inhibition of ICAM-1 expression is due to an antisense activity.

The antisense oligonucleotide COMPOUND 2 at a concentration of 1 μM was shown to inhibit expression of ICAM-1 on human umbilical vein endothelial cells stimulated with either tumor necrosis factor or interleukin-1. These data demonstrate that the effects of COMPOUND 2 are not specific for stimulation of cells by a particular cytokine. Example 3 Cell adherence assay

A second cellular assay which was used to demonstrate the effects of antisense oligonucleotides on ICAM-1, VCAM-1 or ELAM-1 expression was a cell adherence assay. Target cells were grown as a monolayer in a multiwell plate, treated with oligonucleotide followed by cytokine. The adhering cells were then added to the monolayer cells and incubated for 30 to 60 minutes at 37°C and washed to remove nonadhering cells. Cells adhering to the monolayer may be determined either by directly counting the adhering cells or prelabeling the cells with a radioisotope such as ⁵¹Cr and quantitating the radioactivity associated with the monolayer as described. Dustin and Springer, J. Cell Biol . 1988, 107, 321-331.

An example of the effects of antisense oligonucleotides targeting ICAM-1 mRNA on the adherence of DMSO differentiated HL-60 cells to tumor necrosis factor treated human umbilical vein endothelial cells is as follows. Human umbilical vein endothelial cells were grown to 80% confluence in 12 well plates. The cells were treated with 2 μM oligonucleotide diluted in Opti -MEM containing 8 μM DOTMA for 4 hours at 37°C. The medium was removed and replaced with fresh endothelial cell growth medium (EGM-UV) containing 2 μM of the indicated oligonucleotide and incubated 4 hours at 37°C. Tumor necrosis factor, 1 ng/ml, was added to cells as indicated and cells incubated for an additional 19 hours. The cells were washed once with EGM-UV and 1.6 × 10⁶ HL-60 cells differentiated for 4 days with 1.3% DMSO added. The cells were allowed to attach for 1 hour at 37°C and gently washed 4 times with Dulbecco's phosphate-buffered saline (D-PBS) warmed to 37°C. Adherent cells were detached from the monolayer by addition of 0.25 ml of cold (4°C) phosphate-buffered saline containing 5 mM EDTA and incubated on ice for 5 minutes. The number of cells removed by treatment with EDTA was determined by counting with a hemocytometer. Endothelial cells detached from the monolayer by EDTA treatment could easily be distinguished from HL-60 cells by morphological differences.

In the absence of tumor necrosis factor, 3% of the HL- 60 cells bound to the endothelial cells. Treatment of the endothelial cell monolayer with 1 ng/ml tumor necrosis factor increased the number of adhering cells to 59% of total cells added. Treatment with the antisense oligonucleotide COMPOUND 2 or the control oligonucleotide COMPOUND 5 did not change the number of cells adhering to the monolayer in the absence of tumor necrosis factor treatment. The antisense oligonucleotide, COMPOUND 2, reduced the number of adhering cells from 59% of total cells added to 17% of the total cells added. In contrast, the control oligonucleotide, COMPOUND 5, did not significantly reduce the number of cells adhering to the tumor necrosis factor treated endothelial monolayer, i.e., 53% of total cells added for COMPOUND 5 treated cells versus 59% for control cells.

These data indicate that antisense oligonucleotides are capable of inhibiting ICAM-1 expression on endothelial cells and that inhibition of ICAM-1 expression correlates with a decrease in the adherence of a neutrophil-like cell to the endothelial monolayer in a sequence specific fashion. Because other molecules, such as ELAM-1 and VCAM-1, also mediate adherence of white blood cells to endothelial cells, it is not expected that adherence would be completely blocked by antisense to ICAM-1.

Example 4 Cell culture and treatment with oligonucleotides

The human lung carcinoma cell line A549 was obtained from the American Type Culture Collection (Bethesda MD). Cells were grown in Dulbecco's Modified Eagle's Medium (Irvine Scientific, Irvine CA) containing 1 gm glucose/liter and 10% fetal calf serum (Irvine Scientific). Human umbilical vein endothelial cells (HUVEC) (Clonetics, San Diego CA) were cultured in EGM-UV medium (Clonetics). HUVEC were used between the second and sixth passages. Human epidermal carcinoma A431 cells were obtained from the American Type Culture Collection and cultured in DMEM with 4.5 g/1 glucose. Primary human keratinocytes were obtained from Clonetics and grown in KGM (Keratinocyte growth medium, Clonetics).

Cells grown in 96-well plates were washed three times with Opti-MEM (GIBCO, Grand Island, NY) prewarmed to 37°C. 100 μl of Opti-MEM containing either 10 μg/ml N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTMA, Bethesda Research Labs, Bethesda MD) in the case of HUVEC cells or 20 μg/ml DOTMA in the case of A549 cells was added to each well. Oligonucleotides were sterilized by centrifugation through 0.2 μm Centrex cellulose acetate filters (Schleicher and Schuell, Keene, NH). Oligonucleotides were added as 20x stock solution to the wells and incubated for 4 hours at 37°C. Medium was removed and replaced with 150 μl of the appropriate growth medium containing the indicated concentration of oligonucleotide. Cells were incubated for an additional 3 to 4 hours at 37°C then stimulated with the appropriate cytokine for 14 to 16 hours, as indicated. ICAM-1 expression was determined as described in Example 2. The presence of DOTMA during the first 4 hours incubation with oligonucleotide increased the potency of the oligonucleotides at least 100- fold. This increase in potency correlated with an increase in cell uptake of the oligonucleotide.

Example 5 ELISA screening of additional antisense oligonucleotides for activity against ICAM-1 gene expression in Interleukin-1ß-stimulated cells

Antisense oligonucleotides were originally targeted to five sites on the human ICAM-1 mRNA. Oligonucleotides were synthesized in both phosphodiester (P=O; ISIS 1558, 1559, 1563,

1564 and 1565) and phosphorothioate (P=S; ISIS 1570, 1571, 1572, 1573, and 1574) forms. The oligonucleotides are shown in Table 1.

Based on the initial data obtained with the five original targets, additional oligonucleotides targeted to the ICAM-1 mRNA were tested. The antisense oligonucleotide (ISIS 3067) which is targeted to the predicted transcription initiation site (5' cap site) inhibited ICAM-1 expression by nearly 90% in IL-1ß-stimulated cells. ISIS 1931 and 1932 are targeted 5' and 3', respectively, to the AUG translation initiation codon. All three oligonucleotides targeted to the AUG region inhibit ICAM-1 expression, though ISIS 1932 yielded approximately 20% inhibition and thus was less active than ISIS 1570 (70% inhibition) or ISIS 1931 (>50% inhibition). Oligonucleotides targeted to the coding region of ICAM-1 mRNA (ISIS 1933, 1934, 1935, 1574 and 1936) exhibited weak activity. Oligonucleotides targeted to the translation termination codon (ISIS 1937 and 1938) exhibited moderate activity, e.g., over 50% inhibition in the case of ISIS 1938.

Surprisingly, the most active antisense oligonucleotide was ISIS 1939, a phosphorothioate oligonucleotide targeted to a sequence in the 3'- untranslated region of ICAM-1 mRNA (see Table 1) . This oligonucleotide gave complete inhibition of ICAM-1 expression. Oligonucleotides targeted to other 3' untranslated sequences (ISIS 1572, 1573 and 1940) were not as active as ISIS 1939.

Because ISIS 1939 unexpectedly exhibited the greatest antisense activity of the original 16 oligonucleotides tested, other oligonucleotides targeted to sequences in the 3'-untranslated region of ICAM-1 mRNA (ISIS 2302, 2303, 2304, 2305, and 2307, as shown in Table 1) were tested. ISIS 2307, which is targeted to a site only five bases 3' to the ISIS 1939 target, was the least active of the series, and still showed nearly 70% inhibition of ICAM expression. ISIS 2302, which is targeted to the ICAM-1 mRNA at a position 143 bases 3' to the ISIS 1939 target, was the most active of the series, with nearly 100% inhibition. Examination of the predicted RNA secondary structure of the human ICAM-1 mRNA 3'-untranslated region (according to M. Zuker, Science 1989, 244, 48-52) revealed that both ISIS 1939 and ISIS 2302 are targeted to sequences predicted to be in a stable stem- loop structure. However, it is generally believed that regions of RNA secondary structure should be avoided when designing antisense oligonucleotides. Thus, ISIS 1939 and ISIS 2302 would not have been predicted to inhibit ICAM-1 expression.

The control oligonucleotide ISIS 1821 showed a small amount of activity against ICAM expression, probably due in part to its ability to hybridize (12 of 13 base match) to the ICAM-1 mRNA at a position 15 bases 3' to the AUG translation initiation codon.

These studies indicate that the AUG translation initiation codon and specific 3'-untranslated sequences in the ICAM-1 mRNA were the most susceptible to antisense oligonucleotide inhibition of ICAM-1 expression.

In addition to inhibiting ICAM-1 expression in human umbilical vein cells and the human lung carcinoma cells (A549), ISIS 1570, ISIS 1939 and ISIS 2302 were shown to inhibit ICAM-1 expression in primary human keratinocytes by nearly 70%, over 80% and over 80%, respectively. These oligonucleotides also inhibited ICAM-1 expression in the human epidermal carcinoma A431 cells. These data demonstrate that antisense oligonucleotides are capable of inhibiting ICAM-1 expression in several human cell lines. Furthermore, the rank order potency of the oligonucleotides is the same in the four cell lines examined. Example 6 Specificity of antisense inhibition of ICAM-1

The specificity of the antisense oligonucleotides ISIS 1570 and ISIS 1939 for ICAM-1 was evaluated by immunoprecipitation of ³⁵S-labelled proteins. A549 cells were grown to confluence in 25 cm² tissue culture flasks and treated with antisense oligonucleotides as described in Example 4. The cells were stimulated with interleukin-1ß for 14 hours, washed with methionine-free DMEM plus 10% dialyzed fetal calf serum, and incubated for 1 hour in methionine-free medium containing 10% dialyzed fetal calf serum, 1 μM oligonucleotide and interleukin-1ß as indicated. ³⁵S-Methionine/cysteine mixture (Tran³⁵S-label, purchased from ICN, Costa Mesa, CA) was added to the cells to an activity of 100 μCi/ml and the cells were incubated an additional 2 hours. Cellular proteins were extracted by incubation with 50 mM Tris-HCl pH 8.0, 150 mM NaCl, 1.0% NP-40, 0.5% deoxycholate and 2 mM EDTA (0.5 ml per well) at 4°C for 30 minutes. The extracts were clarified by centrifugation at 18,000 × g for 20 minutes. The supernatants were preadsorbed with 200 μl protein G-Sepharose beads (Bethesda Research Labs, Bethesda MD) for 2 hours at 4°C, divided equally and incubated with either 5 μg ICAM-1 monoclonal antibody (purchased from AMAC Inc., Westbrook ME) or HLA-A,B antibody (W6/32, produced by murine hybridoma cells obtained from the American Type Culture Collection, Bethesda, MD) for 15 hours at 4°C. Immune complexes were trapped by incubation with 200 μl of a 50% suspension of protein G-Sepharose (v/v) for 2 hours at 4°C, washed 5 times with lysis buffer and resolved on an SDS-polyacrylamide gel. Proteins were detected by autoradiography.

Treatment of A549 cells with 5 units/ml of interleukin-1ß was shown to result in the synthesis of a 95-100 kDa protein migrating as a doublet which was immunoprecipitated with the monoclonal antibody to ICAM-1. The appearance as a doublet is believed to be due to differently glycosylated forms of ICAM-1. Pretreatment of the cells with the antisense oligonucleotide ISIS 1570 at a concentration of 1 μM decreased the synthesis of ICAM-1 by approximately 50%, while 1 μM ISIS 1939 decreased ICAM-1 synthesis to near background. Antisense oligonucleotide ISIS 1940, inactive in the ICAM-1 ELISA assay (Examples 2 and 5) did not significantly reduce ICAM-1 synthesis. None of the antisense oligonucleotides targeted to the ICAM-1 gene had a demonstrable effect on HLA-A, B synthesis, demonstrating the specificity of the oligonucleotides for ICAM-1. Furthermore, the proteins which nonspecifically precipitated with the ICAM-1 antibody and protein G-Sepharose were not significantly affected by treatment with the antisense oligonucleotides. Example 7 Screening of additional antisense oligonucleotides for activity against ICAM-1 by cell adhesion assay

Human umbilical vein endothelial (HUVEC) cells were grown and treated with oligonucleotides as in Example 4. Cells were treated with either ISIS 1939, ISIS 1940, or the control oligonucleotide ISIS 1821 for 4 hours, then stimulated with TNF-c. for 20 hours. Basal HUVEC minimally bound HL-60 cells, while TNF-stimulated HUVEC bound 19% of the total cells added. Pretreatment of the HUVEC monolayer with 0.3 μM ISIS 1939 reduced the adherence of HL-60 cells to basal levels. The control oligonucleotide, ISIS 1821, and ISIS 1940 reduced the percentage of cells adhering from 19% to 9%. These data indicate that antisense oligonucleotides targeting ICAM-1 can specifically decrease adherence of a leukocyte-like cell line

(HL-60) to TNF-α-treated HUVEC. Example 8 ELISA screening of antisense oligonucleotides for activity against ELAM-1 gene expression

Primary human umbilical vein endothelial (HUVEC) cells, passage 2 to 5, were plated in 96-well plates and allowed to reach confluence. Cells were washed three times with Opti-MEM (GIBCO, Grand Island NY). Cells were treated with increasing concentrations of oligonucleotide diluted in Opti-MEM containing 10 μg/ml DOTMA solution (Bethesda Research Labs, Bethesda MD) for 4 hours at 37°C. The medium was removed and replaced with EGM-UV (Clonetics, San Diego CA) plus oligonucleotide. Tumor necrosis factor a was added to the medium (2.5 ng/ml) and the cells were incubated an additional 4 hours at 37 °C .

ELAM-1 expression was determined by ELISA. Cells were gently washed three times with Dulbecco's phosphate-buffered saline (D-PBS) prewarmed to 37°C. Cells were fixed with 95% ethanol at 4°C for 20 minutes, washed three times with D-PBS and blocked with 2% BSA in D-PBS. Cells were incubated with ELAM-1 monoclonal antibody BBA-1 (R&D Systems, Minneapolis MN) diluted to 0.5 μg/ml in D-PBS containing 2% BSA for 1 hour at 37°C. Cells were washed three times with D-PBS and the bound ELAM-1 antibody detected with biotinylated goat anti-mouse secondary antibody followed by β-galactosidase-conjugated streptavidin as described in Example 2.

The activity of antisense phosphorothioate oligonucleotides which target 11 different regions on the ELAM- 1 cDNA and two oligonucleotides which target ICAM-1 (as controls) was determined using the ELAM-1 ELISA. The oligonucleotide and targets are shown in Table 2.

In contrast to what was observed with antisense oligonucleotides targeted to ICAM-1 (Example 5), the most potent oligonucleotide modulator of ELAM-1 activity (ISIS 2679) was targeted to a specific sequence in the 5' -untranslated region of ELAM-1. This oligonucleotide completely inhibited ELAM-1 expression. ISIS 2687, an oligonucleotide which targeted to sequences ending three bases upstream of the ISIS 2679 target, showed only 10-15% inhibition. Therefore, ISIS 2679 is targeted to a site on the ELAM-1 mRNA, which is sensitive to inhibition with antisense oligonucleotides. The sensitivity of this site to inhibition with antisense oligonucleotides was not predictable based upon RNA secondary structure predictions or information in the literature.

Example 9 ELISA screening of additional antisense oligonucleotides for activity against ELAM-1 gene expression

Inhibition of ELAM-1 expression by eighteen antisense phosphorothioate oligonucleotides was determined using the

ELISA assay as described in Example 8. The sequence and activity of each oligonucleotide against ELAM-1 are shown in

Table 3. The oligonucleotides indicated by an asterisk (*) have IC50's of approximately 50 nM or below and are preferred. IC50 indicates the dosage of oligonucleotide which results in

50% inhibition of ELAM-1 expression. An additional oligonucleotide targeted to the 3'-untranslated region (ISIS

4728) did not inhibit ELAM expression.

Example 10 ELISA screening of antisense oligonucleotides for activity against VCAM-1 gene expression

Inhibition of VCAM-1 expression by fifteen antisense phosphorothioate oligonucleotides was determined using the ELISA assay approximately as described in Example 8, except that cells were stimulated with TNF-α for 16 hours and VCAM-1 expression was detected by a VCAM-1 specific monoclonal antibody (R & D Systems, Minneapolis, MN) used at 0.5 μg/ml.

The sequence and activity of each oligonucleotide against VCAM-1 are shown in Table 4. The oligonucleotides indicated by an asterisk (*) have IC₅₀'s of approximately 50 nM or below and are preferred. IC₅₀ indicates the dosage of oligonucleotide which results in 50% inhibition of VCAM-1 expression.

Example 11 Murine models for testing antisense oligonucleotides against ICAM-1

Many conditions which are believed to be mediated by intercellular adhesion molecules are not amenable to study in humans. For example, allograft rejection is a condition which is likely to be ameliorated by interference with ICAM-1 expression, but clearly this must be evaluated in animals rather than human transplant patients. These conditions can be tested in animal models, however, such as the mouse models used here.

Oligonucleotide sequences for inhibiting ICAM-1 expression in murine cells were identified. Murine ICAM-1 has approximately 50% homology with the human ICAM-1 sequence; a series of oligonucleotides which target the mouse ICAM-1 mRNA sequence were designed and synthesized, using information gained from evaluation of oligonucleotides targeted to human ICAM-1. These oligonucleotides were screened for activity using an immunoprecipitation assay.

Murine DCEK-ICAM-1 cells (a gift from Dr. Adrienne Brian, University of California at San Diego) were treated with 1 μM of oligonucleotide in the presence of 20 μg/ml DOTMA/DOPE solution for 4 hours at 37°C. The medium was replaced with methionine-free medium plus 10% dialyzed fetal calf serum and 1 μM antisense oligonucleotide. The cells were incubated for 1 hour in methionine-free medium, then 100 μCi/ml ³⁵S-labeled methionine/cysteine mixture was added to the cells. Cells were incubated an additional 2 hours, washed 4 times with PBS, and extracted with buffer containing 20 mM Tris, pH 7.2, 20 mM KCl, 5 mM EDTA, 1% Triton X- 100 , 0 . 1 mM leupeptin, 10 μg/ml aprotinin , and 1 mM PMSF. ICAM- 1 was immunoprecipitated from the extracts by incubating with a murine-specific ICAM-1 antibody (YNl/1.7.4) followed by protein G-sepharose. The immunoprecipitates were analyzed by SDS-PAGE and autoradiographed. Phosphorothioate oligonucleotides ISIS 3066 and 3069, which target the AUG codon of mouse ICAM-1, inhibited ICAM-1 synthesis by 48% and 63%, respectively, while oligonucleotides ISIS 3065 and ISIS 3082, which target sequences in the 3'-untranslated region of murine ICAM-1 mRNA inhibited ICAM-1 synthesis by 47% and 97%, respectively. The most active antisense oligonucleotide against mouse ICAM-1 was targeted to the 3'-untranslated region. ISIS 3082 was evaluated further based on these results; this 20-mer phosphorothioate oligonucleotide comprises the sequence (5' to 3') TGC ATC CCC CAG GCC ACC AT (SEQ ID NO : 83).

Example 12 Evaluation of ICAM-1 antisense oligonucleotides in bEND.3 murine endothelioma cells

bEND.3 cells were provided by Dr. Werner Risau, Max-Planck-Instiutes, Martinsreid, Germany. Cells were treated with oligonucleotide in the presence of 15 μg/ml DOTMA/DOPE liposome formulation for 4 hours. ICAM-1 expression was induced by treatment with 5 ng/ml human rTNF-α and 1000 u/ml murine IFN-γ for 16 hours. Cells were fixed with ethanol and ICAM-1 expression was quantitated by incubating with ICAM-1 monoclonal antibody (YN1/1.7.4, purified from ascites) followed by a biotinylated goat anti-rat IgG antibody and streptavidin-conjugated ß-galactosidase. Results are expressed as percent control ICAM-1 expression. Both basal and cytokine-treated cells were pretreated with DOTMA.

Phosphorothioate oligonucleotides ISIS 3068, 3069,

3066, 3070, 3065, 3082, 3806, 3083, 3084 and 3099 were screened by ELISA in the bEND.3 murine endothelioma cell line. These oligonucleotides are shown in Table 5.

The bEND.3 cells expressed a basal level of ICAM-1 molecules that increased significantly after treatment with a combination of human TNF-α and murine IFN-γ. All of the oligonucleotides inhibited cytokine-induced ICAM-1 expression compared to control, two oligonucleotides, ISIS 3082 and ISIS 3806, lowered ICAM-1 protein expression to below the basal level of expression. ISIS 3082 was also shown to reduce cytokine-induced ICAM-1 mRNA by greater than 95%. This effect was specific. Control oligonucleotide ISIS 7253 (SEQ ID NO: 95, a random mixture of the four bases at each position in a phosphorothioate 20 mer) and unrelated control oligonucleotide ISIS 1082 (SEQ ID NO: 96) did not reduce ICAM-1 mRNA expression.

Example 13 Antisense oligonucleotide to ICAM-1 increases survival in murine heterotopic heart transplant model

To determine the therapeutic effects of ICAM-1 antisense oligonucleotide in preventing allograft rejection, the murine

ICAM-1 specific oligonucleotide ISIS 3082 was tested for activity in a murine vascularized heterotopic heart transplant model. Hearts from Balb/c mice were transplanted into the abdominal cavity of C3H mice as primary vascularized grafts essentially as described by Isobe et al., Circula tion 1991, 84, 1246-1255. Oligonucleotides were administered by continuous intravenous administration via a 7-day Alzet pump. The mean survival time for untreated mice was 9.2 ± 0.8 days (8, 9, 9, 9, 10, 10 days). Treatment of the mice for 7 days with 5 mg/kg ISIS 3082 increased the mean survival time to 14.3 ± 4.6 days (11, 12, 13, 21 days). Example 14 Additional mouse heterotopic heart transplants:

Other donor/recipient combinations were found to give similar results in the cardiac allograft experiments. Untreated C3H(H-2)^k mice rejected C57BL/10 (H-2)^b vascularized heart allografts at a mean survival time of 7.7 ± 1.4 days (6, 7, 7, 7, 8, 9, 10 days). A 7-day infusion of the unrelated control oligonucleotide, ISIS 1082, at either 5.0 or 10.0 mg/kg/day did not affect allograft survival (7.1 ± 0.7 days). In contrast, infusion of the ICAM-1 antisense oligonucleotide ISIS 3082 prolonged allograft survival in a dose-dependent fashion: 1.25 mg/kg/day prolonged graft survival to 11.0 ± 0 days; 2.5 mg/kg/day prolonged survival to 12.0 ± 2.7 days (9, 10, 12, 13, 16 days), 5.0 mg/kg/day to 14.1 ± 2 .7 days (10, 12, 12, 13, 16, 16, 17, 17 days); and 10.0 mg/kg/day to 15.3 ± 5.8 days (12, 12, 13, 24 days). All are p < 0.01. Extended 14-day treatment with ISIS 3082 (5 mg/kg/day) further increased graft survival up to as much as 30 days (16, 17, 29, 30; mean = 23.0 ± 7.5 days). Similar results were obtained with C57BL/6 (H-2^b) to BALB/c transplants.

The effectiveness of the immunosuppression was documented by histological examination of the grafts on day 6 after transplantation. Syngeneic C57BL/10 hearts transplanted to C57BL/10 recipients showed mild infiltration with mononuclear cells (10% of the myocardium) compared to normal controls. Heart allografts from untreated recipients displayed strong infiltration with mononuclear cells and neutrophils. This effect was associated with severe necrosis and mineralization that formed a dense band that affected 60% of the epicardium, myocardium and papillary muscles. In contrast, heart allografts from recipients treated with ISIS 3082 (5 mg/kg/day) showed only scattered infiltration with mononuclear cells in 20% of the myocardium. The antisense oligonucleotide targeted to ICAM-1 inhibited infiltration and subsequent destruction of heart allograft tissue by host cells.

Example 15 Antisense oligonucleotide to ICAM-1 combined with monoclonal antibody to LFA-1 increases survival indefinitely in murine heterotopic heart transplant model

Monoclonal antibody (MAb-LFA-1) to LFA-1 was obtained from

Dr. Yogita, Juntendo University School of Medicine, Tokyo, Japan.

C3H recipients of C57 BL/10 hearts were untreated or treated with daily i.p. injection for 7 days of MAb-LFA-1 (50 μg/day) alone or in combination with ISIS 3082 (5.0 mg/kg/day, administered by Alzet osmotic pump for 7 days). Treatment with MAb-LFA-1 alone prolonged allograft survival to 14.3 ± 2.7 days. Combined treatment with MAb-LFA-1 and ISIS 3082 for 7 days resulted in indefinite survival of the heart allografts (>150 days; p < 0.001) in all 5 mice so treated. The interaction between two agents (oligonucleotide and immunosuppressant) was assessed by the combination index (CI) method (Chou, T-C. and Talalay, P. Adv. Enz . Regul . 1984, 22, 27) for the doses to achieve x% inhibition (days of graft survival):

for the mutually exclusive case where both drugs have the same or similar modes of action, or the more conservative expression:

for the mutually exclusive case, where each drug has a different mode of action. Computer software (Biosoft, Cambridge UK) was used to determine the CI values. A CI of 1 indicates an additive effect, CI < 1 indicates a synergistic effect and CI > 1 indicates an antagonistic effect.

The CI value calculated for the combination of 5.0 mg/kg/day ISIS 3082 and 50 μg/day anti-LFA-1 monoclonal antibody was 0.001, indicating strong synergism. Example 16 Antisense oligonucleotide to ICAM-1 combined with monoclonal antibody to LFA-1 induces donor-specific transplantation tolerance

Recipients bearing C57BL/10 hearts for 65 days (n=4) were transplanted with donor-type C57BL/10 and third-party BALB/c (H-2^d) skin allografts. Induction of transplantation tolerance was demonstrated by permanent acceptance of donor-type skin grafts (>100 days) and acute rejection of third-party grafts in 9.0 ± 0.0 days. Control C3H mice (n=5) rejected C57BL/10 and BALB/c grafts in 9.2 ± 0.8 days and 8.1 ± 0.6 days, respectively. These results indicate that the combination of ICAM-1 antisense oligonucleotide and monoclonal antibody to LFA-1 induces donor-specific transplantation tolerance.

Example 17 Effects of antisense oligonucleotide to ICAM-1 combined with conventional immunosuppressive drugs The interaction of ISIS 3082 with the immunosuppressive agents rapamycin (RAPA), brequinar (BQR), cyclosporine A (CsA) and anti -lymphocyte serum (ALS) was examined. CsA (Sandoz, Basel, Switzerland) dissolved in cremophor (Sigma, St. Louis MO) was delivered via jugular venous infusion by a 7-day osmotic pump (Alzet, Palo Alto CA). RAPA (Wyeth Ayerst, Rouse Point NY) diluted in 10% Tween 80, 20% N-N-dimethylacetamide and 70% PEG-400 was infused i.v. by 7-day osmotic pump. BQR (DuPont, Wilmington DE) diluted in distilled water was administered every second day, q.o.d, by oral gavage for 7 days. Rabbit anti-mouse ALS (Accurate, New York, NY) was injected once i.p. two days before grafting.

These immunosuppressive modalities act in different ways: ALS decreases the level of T cells, including the alloantigen-specific T cells. Monaco et al., J. Immunol . 1966, 96, 229-238. RAPA inhibits the transduction of signals delivered by lymphokines (Morice et al., J. Biol . Chem. 1993, 268, 3734- 3738) and BQR blocks the dehydroorotate dehydrogenase enzyme that is required for pyrimidine synthesis [Chen et al., Cancer Res . 1986, 46, 5014-5020]. CsA blocks calcineurin activity, thereby inhibiting the synthesis of lymphokines by T cells. Liu et al., Cell 1991, 66, 807-815.

A single i.p. injection of ALS alone two days prior to transplantation prolonged graft survival in a dose-dependent manner: 0.1 ml gave a mean survival of 9.0 ± 0.0 days; 0.2 ml gave a mean of 10.4 ± 0.5 days (10, 10, 10, 11, 11 days) and 0.4 ml gave a mean survival of 14.0 ± 2.1 days (11, 14, 15, 16 days).

All are p < 0.01. The combination of 0.2 ml ALS and the antisense oligonucleotide ISIS 3082 extended allograft survivals to 32.2 ± 8.3 days (20, 30, 31, 39, 41 days), 37.0 ± 5.8 days

(32, 32, 41, 43 days) and 72.0 ± 49.1 days (33, 34, 54, 89, >150 days), respectively. All are p < 0.01 and CI < 0.001.

RAPA alone (0.05, 0.1 or 0.2 mg/kg/day) delivered i.v. by a 7-day osmotic pump prolonged graft survival in a dose-dependent manner: 0.05 mg/kg/day gave a mean survival of 7.4 ± 1.4 days (6, 6, 7, 9, 9 days); 0.1 mg/kg/day gave a mean survival of 13.0 ± 7.5 days (10, 11, 20, 20, 21 days) and 0.2 mg/kg/day gave a mean survival of 20.0 ± 10.9 days (12, 14, 17, 18, 39 days). The combination of 0.1 mg/kg/day RAPA and the antisense oligonucleotide ISIS 3082 extended allograft survivals to 32.4 ± 8.9 days (23, 24, 33, 39, 43 days) at 5 mg/kg/day of ISIS 3082 and 36.3 ± 6.1 days (32, 32, 36, 45 days) at 10 mg/kg/day of ISIS 3082. Both are p < 0.01 and CI < 0.02.

Oral gavage with BQR alone (0.5, 1.0 or 2.0 mg/kg/day) delivered every second day (q.o.d.) for 7 days prolonged allograft survival to 12.0 ± 2.4 days (9, 11, 11, 14, 15 days), 17.6 days (13, 16, 18, 19, 22 days) or 20.0 ± 4.1 days (15, 17, 20, 23, 25 days), respectively. The combination of 0.5 mg/kg BQR and 5.0 mg/kg ISIS 3082 resulted in a mean survival time of 38.8 ± 30.2 days (21, 24, 28, 28, 31, >100) (p <0.01; CI = 0.007).

A 7-day i.v. infusion of CsA, 2.5 or 5.0 mg/kg/day, was ineffective; 10.0 or 20.0 mg/kg/day CsA did prolong allograft survival. Addition of ISIS 3082 (5.0 or 10.0 mg/kg/day) to CsA treatment (5.0 mg/kg/day) did not improve graft survival. CI was 14.1 and 51.0, respectively. A combination of the control oligonucleotide, ISIS 1082, and CsA did not affect graft survival time.

These results show that the ICAM-1 antisense oligonucleotide ISIS 3082 interacts synergistically with the immunosuppressive agents ALS, RAPA and BQR, but not with CsA, to block allograft rejection. Because CsA is not very effective in mice, it is unclear whether the lack of synergism between the antisense oligonucleotide and CsA is a pharmacological or a pharmacokinetic effect.

Example 18 Toxicology and pharmacokinetics of ISIS 3082

The ICAM-1 antisense oligonucleotide ISIS 3082 was well tolerated at therapeutic doses without producing signs of toxicity. Even at high doses (100.0 mg/kg/day given q.o.d for 14 days), ISIS 3082 did not produce any major side effects and did not induce an antigenic response.

Interestingly, ISIS 3082 was shown to be active in prolonging heart allograft survival when delivered in a saline suspension, without cationic liposomes. Similar observations have been made with other phosphorothioate oligonucleotides directed at other targets (see, for example, Simons et al., Nature 1992, 359, 67-70; Kitaj ima et al., Science 1992, 258, 1792-1795). Thus, although cationic liposomes enhance the effect of many oligonucleotides, including ISIS 3082, in vi tro, they are not necessarily required for efficacy of the same oligonucleotides in vivo.

Example 19 Mouse pancreatic islet transplants

Fully H-2 and non-H-2 incompatible C3H (H-2^K) streptozotocin-induced diabetic mice were transplanted with 700 fresh C57 BL/10 (H-2^b) dextran gradient-purified islet cells, into either the renal subcapsular space or embolized through the portal vein to the liver. All animals analyzed had non-fasting blood sugars less than 200 mg/dl within 4 post-operative days. The day of rejection was defined as the first day of two consecutive blood sugars >300 mg/dl and was documented histologically.

Glucose tolerance tests were done at postoperative days 2 and 7. After a 4 -hour fast, the control and oligonucleotide-treated groups were given 2 grams dextrose/kg body weight IP. Blood sugars were recorded at 0, 15, 30, 45 and 90 minutes.

Example 20 Effect of anti-ICAM-1 oligonucleotide ISIS 3082 or monoclonal antibodies on pancreatic islet graft survival and islet function

Graft survival: There were four treatment groups following kidney capsule transplantation. 1) Mice receiving no immunosuppressive treatment (control) had a mean survival time

(MST) ± standard deviation of 10.7 ± 2.3 days. 2) Mice treated with anti-LFA-1 monoclonal antibody, 50 mg daily IP for 7 days had a MST of 27.2 ± 4.8 days, p <0.01. 3) Mice treated with anti- ICAM-1 monoclonal antibody YNl/1.7.4, 100 μg IP daily for 7 days, had a MST of 21.9 ± 2.0 days, p < 0.01. 4) Mice treated with anti-ICAM-1 oligonucleotide ISIS 3082 (SEQ ID NO: 83), 5 mg/kg/day IP via osmotic pump had a MST of 28.9 ± 12 days, p< 0.01.

After portal vein administration, control mice survived 11.2 ± 2.6 days and ISIS 3082 oligonucleotide-treated mice had a MST of 30.0 ± 18 days, p < 0.01.

Glucose tolerance tests: On postoperative day 2, the oligonucleotide-treated group had lower mean blood sugars compared to controls at 30 minutes (142.6 ± 72 vs. 231.3 ± 53.8, p < 0.05) and 45 minutes (100.4 + 68.4 vs. 199.5 ± 62.1, p < 0.5). On postoperative day 7, the oligonucleotide-treated group also had lower mean blood sugars compared to controls at 30 minutes (189 ± 58.5 vs. 251.5 ± 70.1, p < 0.05) and 45 minutes 148.6 ± 40.2 vs. 210.7 ± 58.2, p < 0.5).

Significant islet allograft prolongation was achieved by ICAM-1 blockade. ICAM-1 antisense oligonucleotide was effective in improving islet function as well as prolonging graft survival. Example 21 Identification of rat oligonucleotides in vi tro

Oligonucleotide sequences for inhibiting rat ICAM-1 expression were identified and screened in rat L2 cells. The most active sequence, ISIS 9125 (SEQ ID NO: 100), displayed an EC₅₀ of approximately 150 nm. Sense and scrambled control sequences had no activity at doses from 150 nm to 1 μM.

Example 22 Rat kidney allografts

Kidneys from Lewis rats were transplanted into ACI rats. Control rats (no oligonucleotide treatment) had a mean graft survival time of 8.5 +.1.0 days (7, 8, 8, 9, 9, 10 days).

Rats treated with oligonucleotide ISIS 9125 alone (10 mg/kg per day) for 7 days had a mean graft survival time of 9.2 +_.1.3 days

(8, 9, 9, 11 days). Rats treated with oligonucleotide ISIS 9125 alone (10 mg/kg per day) for 14 days had a mean graft survival time of >18.3 days (18, >7, >30 days).

Example 23 Rat kidney allografts with cyclosporin

Kidneys from Lewis rats were transplanted into ACI rats. Control rats (no oligo, no cyclosporin) had a mean graft survival time of 8.5 ± 1.0 days (7, 8, 8, 9, 9, 9, 10 days). Cyclosporin alone (2 mg/kg daily for 7 days) increased graft survival time to 10.5 ± 3.4 days (7, 9, 11, 15 days). Rats treated with oligonucleotide ISIS 9125 alone (10 mg/kg per day for 7 days) had a mean graft survival time of 9.25 days (8, 9, 9, 11 days). Rats treated with both cyclosporin (2 mg/kg × 7 days) and oligonucleotide ISIS 9125 (10 mg/kg × 7 days) had a mean graft survival time of >24.2 days (10, 12, 24, -30, >45 days). Treatment with a reduced cyclosporin dose of 1 mg/kg for 14 days (no oligonucleotide) gave a mean graft survival time of >17.0 days (15, 18, >18). This cyclosporin regimen in combination with ISIS 9125 (10 mg/kg, 14 days) gave a mean graft survival time of >30 days (>30, >30, >30).

Example 24 Rat cardiac allografts

Hearts from Lewis rats were transplanted into ACI rats using a modification of the method described in Example 12. Control rats (no oligonucleotide treatment) had a mean graft survival time of 8.8 ± 0.8 days (8, 8, 9, 9, 9, 10 days). Rats treated with oligonucleotide ISIS 9125 alone (2.5 mg/kg for 7 days) had a mean graft survival time of 12.0 ± 1.7 days (10, 13, 13 days), rats treated with oligonucleotide ISIS 9125 alone (5 mg/kg for 7 days) had a mean graft survival time of 10 ± 3.0 days (7, 10, 13 days) and rats treated with ISIS 9125 alone (10 mg/kg per day for 7 days) had a mean graft survival time of 18.0 ± 3.8 days (13, 16, 16, 18, 22, 23 days). Example 25 Rat cardiac allografts with cyclosporin

Hearts from Lewis rats were transplanted into ACI rats as above. Control rats (no oligo, no cyclosporin) had a mean graft survival time of 8.8 ± 0.8 days (8, 8, 9, 9, 9, 10 days). Cyclosporin alone (2 mg/kg daily for 7 days) increased graft survival time to 13.7 ± 1.5 days (12, 14, 15 days) and cyclosporine alone (4 mg/kg for 7 days) gave a graft survival time of 16.7 ± 3.8 days (14, 15, 21 days). Rats treated with oligonucleotide ISIS 9125 alone (5 mg/kg for 7 days) had a mean graft survival time of 10 ± 3.0 days (7, 10, 13 days) and rats treated with ISIS 9125 alone (10 mg/kg per day for 7 days) had a mean graft survival time of 18.0 ± 3.8 days (13, 16, 16, 18, 22, 23 days). Rats treated with both cyclosporin (4 mg/kg × 7 days) and oligonucleotide ISIS 9125 (10 mg/kg × 7 days) had a mean graft survival time of 21.7 ± 7.4 days (16, 19, 30 days).

Claims

What is claimed is:

1. A composition for treating allograft rejection comprising an oligonucleotide 8 to 50 nucleotides in length which is targeted to a nucleic acid sequence encoding ICAM-1, ELAM-1 or VCAM-1 in combination with an immunosuppressive agent.

2. The composition of claim 1 wherein the oligonucleotide comprises SEQ ID NO: 22.

3. The composition of claim 1 wherein the immunosuppressive agent is a monoclonal antibody.

4. The composition of claim 2 wherein the monoclonal antibody is directed against LFA-1.

5. The composition of claim 1 wherein the immunosuppressive agent is brequinar, rapamycin or anti-lymphocyte serum.

6. The composition of claim 1 wherein the immunosuppressive agent is an antisense oligonucleotide.

7. A method of preventing allograft rejection in an allograft recipient comprising treating the allograft recipient with an oligonucleotide 8 to 50 nucleotides in length which is targeted to a nucleic acid sequence encoding ICAM-1, ELAM-1 or VCAM-1, in combination with an immunosuppressive agent.

8. The method of claim 7 wherein the immunosuppressive agent is a monoclonal antibody.

9. The method of claim 8 wherein the monoclonal antibody is directed against LFA-1.

10. The method of claim 7 wherein the immunosuppressive agent is brequinar, rapamycin or anti-lymphocyte serum.

11. The method of claim 7 wherein the immunosuppressive agent is an antisense oligonucleotide.

12. The method of claim 7 wherein the allograft is a cardiac allograft.

13. The method of claim 7 wherein the allograft is a renal allograft.

14. A method of preventing allograft rejection in an allograft recipient comprising treating the allograft recipient with a composition of claim 1.

15. A method of preventing rejection of an allograft by an allograft recipient comprising treating the allograft with a composition of claim 1.

16. The method of claim 15 wherein the treatment is performed ex vivo.

17. A method of preventing rejection of an allograft comprising treating the allograft with an oligonucleotide 8 to 50 nucleotides in length which is targeted to a nucleic acid sequence encoding ICAM-1, ELAM-1 or VCAM-1.

18. The method of claim 17 wherein the oligonucleotide comprises SEQ ID NO: 22.

19. A method of treating allograft rejection in an allograft recipient comprising treating the allograft recipient with an oligonucleotide 8 to 50 nucleotides in length which is targeted to a nucleic acid sequence encoding ICAM-1, ELAM-1 or VCAM-1 in combination with an immunosuppressive agent.

20. The method of claim 19 wherein the immunosuppressive agent is a monoclonal antibody.

21. The method of claim 20 wherein the monoclonal antibody is directed against LFA-1.

22. The method of claim 19 wherein the immunosuppressive agent is brequinar, rapamycin or anti-lymphocyte serum.

23. The method of claim 19 wherein the immunosuppressive agent is an antisense oligonucleotide.

24. The method of claim 19 wherein the allograft is a cardiac allograft.

25. The method of claim 19 wherein the allograft is a renal allograft.

26. A method of treating allograft rejection in an allograft recipient comprising treating the allograft recipient with a composition of claim 1.