WO2022148816A1

WO2022148816A1 - Inhibition of t-cell activity

Info

Publication number: WO2022148816A1
Application number: PCT/EP2022/050213
Authority: WO
Inventors: Alex BATEMAN; John Bradley; Jun Wang
Original assignee: Cambridge Enterprise Limited; European Molecular Biology Laboratory (Embl)
Priority date: 2021-01-07
Filing date: 2022-01-06
Publication date: 2022-07-14
Also published as: GB202100194D0

Abstract

This invention relates to the inhibition of the proliferation and/or activation of T cells by full-length factor V (FV) protein and peptides derived from full-length FV protein. This may be used to exert an immunosuppressive effect in therapy. FV peptides and proteins and their use in the treatment of autoimmune disorders and other conditions characterised by T cell mediated immune responses are provided.

Description

Inhibition of T-Cell Activity Field The present invention relates to products and compositions for the inhibition of T cell activity and their use in therapy. Background The immune system distinguishes self from non-self. It protects the host from infections by recognising pathogenic microbes as foreign and deploying mechanisms to attack and destroy them. The immune system is also important for surveillance and removal of cancer cells. In some settings, the immune system results in harm. Autoimmunity results from a failure to distinguish self from non-self. In organ transplantation donor tissue is recognised as foreign and an alloimmune response provokes organ rejection. In graft versus host disease donor cells can attack the host’s tissues. In some infections the host’s immune response to the pathogen results in damage to host tissue. Suppression of the immune system is a therapeutic goal in many diseases, including autoimmune diseases and transplant rejection. Current therapeutic approaches encompass the wide-ranging effects of corticosteroids, to targeted approaches that modulate a specific molecular pathway. The wide range of therapies available illustrates the need for specificity in targeting the immune system in different diseases. Immunosuppressant drugs are limited by two broad categories of adverse events. Adverse events may relate to suppression of the immune system and may result in an increased risk of infection and increased susceptibility to cancer. Alternatively, adverse events may be unrelated to the immunosuppressant effect, for example through cytotoxicity to non-immune cells or adverse events unrelated to immunosuppression. There is an unmet need for immunosuppressive drugs that target specific immune cells or pathways, with reduced toxicity and other adverse effects. Summary The present inventors have recognised that full-length factor V (FV) protein and peptides derived from full- length FV protein inhibit the proliferation and/or activation of T cells and exert an immunosuppressive effect. This may be useful, for example for the treatment of autoimmune disorders and other conditions characterised by T cell mediated immune responses. A first aspect of the invention provides an isolated peptide comprising a fragment of SEQ ID NO: 1 or SEQ ID NO: 2 or a variant thereof. In preferred embodiments, a peptide may comprise a fragment of SEQ ID NO: 15 or SEQ ID NO: 16 or a variant thereof. Some preferred peptides may comprise a thrombin cleavage site of Factor V. For example, a peptide may comprise or consist of one or more of SEQ ID NOs: 3 to 11 or a variant thereof. Other preferred peptides may comprise a fragment of SEQ ID NO: 14 or a variant thereof. For example, a peptide may comprise or consist of any one of SEQ ID NOs: 12 to 13 or a variant thereof. A second aspect of the invention provides a pharmaceutical composition comprising one or more isolated peptides of the first aspect and a pharmaceutically acceptable excipient. A third aspect of the invention provides a method of producing a pharmaceutical composition comprising admixing one or more isolated peptides of the first aspect with a pharmaceutically acceptable excipient. A fourth aspect of the invention provides an isolated peptide of the first aspect for use in the treatment of the human or animal body. A fifth aspect of the invention provides a pharmaceutical composition comprising an isolated polypeptide comprising the amino acid sequence of SEQ ID NO: 2 or a variant thereof and a pharmaceutically acceptable excipient. A sixth aspect of the invention provides a method of producing a pharmaceutical composition comprising admixing an isolated polypeptide comprising the amino acid sequence of SEQ ID NO: 2 or a variant thereof with a pharmaceutically acceptable excipient. A seventh aspect of the invention provides an isolated polypeptide comprising the amino acid sequence of SEQ ID NO: 2 or a variant thereof for use in the treatment of the human or animal body. An eighth aspect of the invention provides a method of treatment of a condition characterised by T cell mediated immune responses comprising administering to an individual in need thereof a peptidyl therapeutic agent that comprises the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2, a fragment of said sequence or a variant of said sequence or fragment. A ninth aspect of the invention provides a peptidyl therapeutic agent that comprises the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2, a fragment of said sequence or a variant of said sequence or fragment for use in the treatment of a condition characterised by T cell mediated immune responses. A tenth aspect of the invention provides the use of a peptidyl therapeutic agent that comprises the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2, a fragment of said sequence, or a variant of said sequence or fragment for the manufacture of a medicament for the treatment of a condition characterised by T cell mediated immune responses. The peptidyl therapeutic agent of the eighth to the tenth aspects may be a peptide or polypeptide that comprises the amino acid sequence of any one of SEQ ID NOs: 3 to 13. In some embodiments, the peptidyl therapeutic agent of the eighth to the tenth aspects may be an isolated peptide of the first aspect. Conditions characterised by T cell mediated immune responses in accordance with the eighth to the tenth aspects may include T cell malignancies, such as T cell lymphoma and T cell leukaemia; auto-immune conditions, such as inflammatory bowel disease, rheumatoid arthritis; type 1 diabetes; systemic lupus erythematosus; psoriasis; psoriatic arthritis; and vasculitis; and allo-immune conditions, such as Graft vs Host Disease (GvHD) or transplant rejection. Other aspects and embodiments of the invention are described in more detail below. Brief Description of the Figures Figure 1 shows the structure of Factor V and its activation by thrombin. Figure 2 shows the results of labelling CD4+T conventional cells (Tcon) with carboxyfluorescein diacetate succinimidyl ester (CFSE) (a), and stimulating them with Dynabeads T cell activator (b –i). ). Cells proliferate in response to stimulation, so the dye is diluted and intensity of fluorescence decreases. Decreased fluorescence is therefore indicative of cell proliferation. Histograms are representative of 10 healthy donors (f), F5 at medium concentration suppressed T cell proliferation by 3 to 17 percent (p=0.0003). Medium concentration is close to the physiological plasma level at 20 nM, low concentration is 4 nM, high concentration is 100 nM. Proliferation is shown to be inhibited in a concentration dependent manner by addition of native full length Factor V (Figure 2 panels c – e), but not by activated factor V, Factor Va (Figure 2 panels g – i). Figure 3 shows the results of stimulating Tcon cells with Dynabeads T cell activator in the presence or absence of recombinant B domain (Construct 1; Factor V 738 - 1573), recombinant full length Factor V ( construct 2) and mutated Factor V (construct 3; Factor V R709A, R1018A, R1545A). Tcon proliferation was not inhibited by construct 1, and thrombin and hirudin had no effect on their own and in combination with construct 1. Construct 2 inhibited Tcon proliferation just as native Factor V, and its effect was prevented by thrombin (p=0.036), while the effect of inhibition by construct 3 was not prevented by thrombin (p=0.25). Figure 4 shows the results of stimulating CD8 T cells with Dynabeads T cell activator in the presence or absence of recombinant B domain (Construct 1), recombinant full length Factor V (construct 2) and mutated Factor V (construct 3).CD8+ T cell proliferation was inhibited by construct 2 (p=0.009) and construct 3 (p=0.004), while B cell proliferation was not inhibited by any of the constructs (p=0.1; p=0.3; p=0.6). Figure 5 shows a diagram of Factor V showing basic region, acidic region, and regions of peptides. Figure 6 shows the results of stimulating CD4 T cells with Dynabeads T cell activator in the presence or absence of peptides derived from Factor V. Peptide sequences are described in Table 1. Figure 7 shows the results of stimulating T cells with Dynabeads T cell activator in the presence or absence of further peptides derived from Factor V. Peptide sequences are described in Table 1. Detailed Description This invention relates to peptides derived from modified full-length factor V (FV) and the use of modified full- length factor V (FV) polypeptides and peptides derived therefrom to inhibit T cell proliferation and/or activation. In some embodiments, T cell proliferation and/or activation may be inhibited directly and not through the action of regulatory T cells (Tregs). The FV polypeptides and peptides described herein may be useful, for example for the treatment of conditions characterised by T cell mediated immune responses. Factor V (FV) is an essential cofactor of the blood coagulation cascade. FV circulates in plasma and is activated through proteolytic cleavage by thrombin into the active form (FVa). Human Factor 5 (Gene ID: 2153) may have the amino acid sequence of NP_000121.2 and may be encoded by the nucleotide sequence of NM_000130.5. An isolated peptide described herein may comprise the amino acid sequence of a fragment of a full-length Factor V sequence or a variant of such a fragment. Full-length Factor V sequences may include the amino acid sequences of SEQ ID NOs: 1 and 2. A fragment of a full-length Factor V sequence, such as SEQ ID NO: 1 or SEQ ID NO: 2, is a contiguous sequence of amino acids from the full-length protein sequence that consists of at least one fewer amino acid than the full-length protein sequence i.e. a fragment may contain fewer amino acids than the 2224 amino acids of the full-length Factor V sequence. For example, a fragment may lack a sequence of 10 or more, 20 or more, 50 or more of 100 or more amino acids relative to the full-length Factor V sequence. Preferred fragments may comprise 100 or fewer, 50 or fewer, 40 or fewer, 30 or fewer, or 20 or fewer amino acids. Preferred fragments may comprise 6 or more, 8 or more, 10 or more, 15 or more, 20 or more, 30 or more or 40 or more amino acids. In some embodiments, a peptide described herein may comprise the amino acid sequence of a fragment of SEQ ID NO: 15 or 16. A preferred fragment may comprise amino acids corresponding to one or more thrombin cleavage sites of Factor V. For example, a fragment may comprise one or more of positions 709, 1018 or 1545 in the full- length Factor V sequence. In some embodiments, the residue at the position in the fragment corresponding to positon 709, 1018 or 1545 is not R and the fragment is not susceptible to cleavage by thrombin. A preferred fragment may comprise amino acids corresponding to the thrombin cleavage site at position 709 of Factor V and/or the thrombin cleavage site at position 1545 of Factor V. In some embodiments, a fragment described herein may comprise the amino acid sequence of residues 700 to 718 of human Factor V or a variant thereof. For example, an isolated peptide may comprise the amino acid sequence of SEQ ID NO: 3 or SEQ ID NO: 4, a variant of said amino sequence, or a fragment of said amino acid sequence or variant. NRLAAALGIRSFRNSSLNQ (SEQ ID NO: 3) NRLAAALGIKSFRNSSLNQ (SEQ ID NO: 4) In other embodiments, a fragment described herein may comprise the amino acid sequence of residues 1009 to 1027 of human Factor V or a variant thereof. For example, an isolated peptide may comprise the amino acid sequence of SEQ ID NO: 5 or SEQ ID NO: 6, a variant of said amino sequence, or a fragment of said amino acid sequence or variant. HTHHAPLSPRTFHPLRSEA (SEQ ID NO: 5) HTHHAPLSPKTFHPLRSEA (SEQ ID NO: 6) In other embodiments, a fragment described herein may comprise the amino acid sequence of residues 1536 to 1555 of human Factor V or a variant thereof. For example, an isolated peptide may comprise the amino acid sequence of SEQ ID NO: 7 or SEQ ID NO: 8, a variant of said amino sequence, or a fragment of said amino acid sequence or variant. PDNIAAWYLRSNNGNRRNY (SEQ ID NO: 7) PDNIAAWYLKSNNGNRRNY (SEQ ID NO: 8) In other embodiments, a fragment described herein may comprise the amino acid sequence of residues 1300 to 1319 of human Factor V or a variant thereof. For example, an isolated peptide may comprise the amino acid sequence of SEQ ID NO: 12, a variant of said amino sequence, or a fragment of said amino acid sequence or variant. GQMPISPDLSHTTLSPDLSH (SEQ ID NO: 12) In other embodiments, a fragment described herein may comprise the amino acid sequence of residues 1296 to 1330 of human Factor V or a variant thereof. For example, an isolated peptide may comprise the amino acid sequence of SEQ ID NO: 13, a variant of said amino sequence, or a fragment of said amino acid sequence or variant. SPALGQMPISPDLSHTTLSPDLSHTTLSLDLSQTN (SEQ ID NO: 13) An isolated peptide described herein may inhibit T cell proliferation and/or activation, such as CD4 T cell and CD8 T cell proliferation and/or activation. Preferably, the isolated peptide inhibits CD4 T cell proliferation and/or activation. Preferably, the isolated peptide does not inhibit B cell proliferation. Preferably, the isolated peptide is thrombin resistant. For example, the peptide may be devoid of thrombin cleavage sites, such that it is not susceptible to proteolytic cleavage by thrombin. In some embodiments, an amino acid residue in the peptide corresponding to R709 in human Factor V (denoted X1 in SEQ ID NOs: 2 and 9) may be an amino acid residue other than R, preferably an amino acid residue other than R or Q. For example, the amino acid residue corresponding to R709 in human Factor V (denoted X1 in SEQ ID NOs: 2 and 9) may be K or A. An amino acid residue in the peptide corresponding to R1018 in human Factor V (denoted X2 in SEQ ID NO: 2 and SEQ ID NO: 10) may be an amino acid residue other than R, preferably an amino acid residue other than R or Q. For example, the amino acid residue corresponding to R1018 in human Factor V (denoted X2 in SEQ ID NO: 2 and SEQ ID NO: 10) may be K or A. An amino acid residue in the peptide corresponding to R1545 in human Factor V (denoted X3 in SEQ ID NO: 2 and SEQ ID NO: 11) may be an amino acid residue other than R, preferably an amino acid residue other than R or Q. For example, the amino acid residue corresponding to R1545 in human Factor V (denoted X3 in SEQ ID NO: 2 and SEQ ID NO: 11) may be K or A. For example, an isolated peptide may comprise the amino acid sequence of SEQ ID NO: 9, SEQ ID NO: 10 or SEQ ID NO: 11 or a variant of any of these sequences. NRLAAALGIX₁SFRNSSLNQ (SEQ ID NO: 9) HTHHAPLSPX₂TFHPLRSEA (SEQ ID NO: 10) PDNIAAWYLX3SNNGNRRNY(SEQ ID NO: 11) where X1, X2 and X3 are independently, any residue other than R, preferably A or K. The isolated peptide may also be resistant to proteolytic cleavage by Factor Xa. An amino acid sequence described herein that is a variant of a reference sequence, such as a peptide, polypeptide or protein sequence described herein, may have 1 or more amino acid residues altered relative to the reference sequence. For example, 50 or fewer amino acid residues may be altered relative to the reference sequence, preferably 45 or fewer, 40 or fewer, 30 or fewer, 20 or fewer, 15 or fewer, 10 or fewer, 5 or fewer or 3 or fewer, 2 or 1. For example, a variant described herein may comprise the sequence of a reference sequence with 50 or fewer, 45 or fewer, 40 or fewer, 30 or fewer, 20 or fewer, 15 or fewer, 10 or fewer, 5 or fewer, 3 or fewer, 2 or 1 amino acid residues mutated. An amino acid residue in the reference sequence may be altered or mutated by insertion, deletion or substitution, preferably substitution for a different amino acid residue. Such alterations may be caused by one or more of addition, insertion, deletion or substitution of one or more nucleotides in the encoding nucleic acid. A peptide, polypeptide or protein as described herein that is a variant of a reference sequence, such as an amino acid sequence described above, may share at least 50% sequence identity with the reference amino acid sequence, at least 55%, at least 60%, at least 65%, at least 70%, at least about 80%, at least 90%, at least 95%, at least 98% or at least 99% sequence identity. For example, a variant of a protein described herein may comprise an amino acid sequence that has at least 50% sequence identity with the reference amino acid sequence, at least 55%, at least 60%, at least 65%, at least 70%, at least about 80%, at least 90%, at least 95%, at least 98% or at least 99% sequence identity with the reference amino acid sequence, for example one or more of SEQ ID NOS: 1 to 15. Sequence identity is commonly defined with reference to the algorithm GAP (Wisconsin GCG package, Accelerys Inc, San Diego USA). GAP uses the Needleman and Wunsch algorithm to align two complete sequences that maximizes the number of matches and minimizes the number of gaps. Generally, default parameters are used, with a gap creation penalty = 12 and gap extension penalty = 4. Use of GAP may be preferred but other algorithms may be used, e.g. BLAST (which uses the method of Altschul et al. (1990) J. Mol. Biol.215: 405-410), FASTA (which uses the method of Pearson and Lipman (1988) PNAS USA 85: 2444-2448), or the Smith-Waterman algorithm (Smith and Waterman (1981) J. Mol Biol.147: 195-197), or the TBLASTN program, of Altschul et al. (1990) supra, generally employing default parameters. In particular, the psi-Blast algorithm may be used (Nucl. Acids Res. (1997) 253389-3402). Sequence identity and similarity may also be determined using Genomequest^TM software (Gene-IT, Worcester MA USA). Sequence comparisons are preferably made over the full-length of the relevant sequence described herein. A peptide described herein may further comprise one or more heterologous amino acid sequences additional to the FV fragment. For example, the peptide may further comprise one or more additional domains, which improve stability, pharmacokinetics, targeting, affinity, purification and/or production properties. A peptide described herein may be provided using synthetic or recombinant techniques which are standard in the art. In some embodiments, a peptide may be generated wholly or partly by chemical synthesis. For example, a peptide may be synthesised using liquid or solid-phase synthesis methods; in solution; or by any combination of solid-phase, liquid phase and solution chemistry, e.g. by first completing the respective peptide portion and then, if desired and appropriate, after removal of any protecting groups being present, by introduction of the residue X by reaction of the respective carbonic or sulfonic acid or a reactive derivative thereof. In some embodiments, a peptide may be synthesised in solution, by the liquid phase method or by any combination of solid-phase, liquid phase and solution chemistry, e.g. by first completing the respective peptide portion and then, if desired and appropriate, after removal of any protecting groups being present, by introduction of the residue X by reaction of the respective carbonic or sulfonic acid or a reactive derivative thereof.. For example, peptides may be synthesized by Fmoc (N-(9-fluorenyl) methoxycarbonyl) chemistry as C-terminal amides on TentaGel R RAM resin in an automated synthesizer (e.g. Applied Biosystems Pioneer^TM). Chemical synthesis of peptides and polypeptides is well-known in the art (J.M. Stewart and J.D. Young, Solid Phase Peptide Synthesis, 2nd edition, Pierce Chemical Company, Rockford, Illinois (1984); M. Bodanzsky and A. Bodanzsky, The Practice of Peptide Synthesis, Springer Verlag, New York (1984); J. H. Jones, The Chemical Synthesis of Peptides. Oxford University Press, Oxford 1991; in Applied Biosystems 430A User’s Manual, ABI Inc., Foster City, California; G. A. Grant, (Ed.) Synthetic Peptides, A User’s Guide. W. H. Freeman & Co., New York 1992, E. Atherton and R.C. Sheppard, Solid Phase Peptide Synthesis, A Practical Approach. IRL Press 1989 and in G.B. Fields, (Ed.) Solid-Phase Peptide Synthesis (Methods in Enzymology Vol.289). Academic Press, New York and London 1997). A peptide described herein may be isolated, in the sense of being free from contaminants, such as other polypeptides and/or cellular components. In some embodiments, an isolated peptide described herein may be chemically modified, for example, by addition of one or more polyethylene glycol molecules, sugars, phosphates, and/or other such molecules, where the molecule or molecules are not naturally attached to wild-type FV. Suitable chemical modifications are well known to those of skill in the art. The same type of modification may be present in the same or varying degree at several sites in the peptide. In addition, a given peptide may contain multiple different modifications. Modifications can occur anywhere in the peptide sequence, including the peptide backbone, the amino acid side-chains, and the amino or carboxyl termini. Modifications include, for example, acetylation, acylation, ADP-ribosylation, amidation, covalent attachment of flavin, covalent attachment of a haem moiety, covalent attachment of a nucleotide or nucleotide derivative, covalent attachment of a lipid or lipid derivative, covalent attachment of phosphatidylinositol, cross-linking, cyclization, disulfide bond formation, demethylation, formation of covalent cross-links, formation of cysteine, formation of pyroglutamate, formylation, gamma- carboxylation, glycosylation, GPI anchor formation, hydroxylation, iodination, methylation, myristoylation, oxidation, proteolytic processing, phosphorylation, prenylation, racemization, lipid attachment, sulfation, gamma-carboxylation of glutamic acid residues, hydroxylation and ADP-ribosylation, selenoylation, sulfation, transfer-RNA mediated addition of amino acids to proteins, such as arginylation, and ubiquitination. See, for instance, Proteins-Structure and Molecular Properties, 2nd Ed., T. E. Creighton, W. H. Freeman and Company, New York (1993) and Wold, F., "Posttranslational Protein Modifications: Perspectives and Prospects," pgs.1-12 in Posttranslational Covalent Modification Of Proteins, B. C. Johnson, Ed., Academic Press, New York (1983); Seifter et al., Meth. Enzymol.182:626-646 (1990) and Rattan et al., "Protein Synthesis: Posttranslational Modifications and Aging," Ann. N.Y. Acad. Sci.663: 48-62 (1992). In some embodiments, a protecting group may be coupled to the N- and/or C-terminal end of a peptide to protect the peptide from enzymatic digestion. Suitable protecting groups are well-known in the art. An isolated peptide as described herein may be structurally modified. A structurally modified peptide is substantially similar in both three-dimensional shape and biological activity to a peptide described herein and preferably comprises a spatial arrangement of reactive chemical moieties that closely resembles the three- dimensional arrangement of active groups in the peptide sequence. Examples of structurally modified peptides include pseudo-peptides, semi-peptides and peptoids. An isolated peptide as described herein may be structurally modified to include one or more non-peptidyl bonds, for example pseudopeptide bonds. A number of suitable pseudopeptide bonds are known in the art, including retro-inverso pseudopeptide bonds ("Biologically active retroinverso analogues of thymopentin", Sisto A. et al in Rivier, J. E. and Marshall, G. R. (eds) "Peptides, Chemistry, Structure and Biology", Escom, Leiden (1990), pp.722-773) and Dalpozzo, et al. (1993), Int. J. Peptide Protein Res., 41:561-566), reduced isostere pseudopeptide bonds (Couder, et al. (1993), Int. J. Peptide Protein Res., 41:181-184), ketomethylene and methylsulfide bonds. An isolated peptide comprising pseudopeptide bonds may have an identical amino acid sequence to the sequence described above, except that one or more of the peptide bonds are replaced by a pseudopeptide bond. In some embodiments, the most N-terminal peptide bond is substituted, since such a substitution will confer resistance to proteolysis by exopeptidases acting on the N-terminus. Further modifications also can be made by replacing chemical groups of the amino acids with other chemical groups of similar structure. An isolated peptide as described herein may be structurally modified to eliminate peptide bonds. Suitable structurally modified peptides include peptoids (Simon, et al., 1992, Proc. Natl. Acad. Sci. USA, 89:9367- 9371), which are oligomers of N-substituted glycines. The N-alkyl group of each glycine residue corresponds to the side chain of a natural amino acid. Some or all of the amino acids of a peptide may be replaced with the N-substituted glycine corresponding to the replaced amino acid. An isolated peptide as described herein may be structurally modified to comprise one or more D-amino acids. For example, a peptide may be an enantiomer in which one or more L-amino acid residues in the amino acid sequence of the peptide is replaced with the corresponding D-amino acid residue or a reverse-D peptide, which is a peptide consisting of D-amino acids arranged in a reverse order as compared to the L- amino acid sequence described above. (Smith C. S. et al., Drug Development Res., 15, pp.371-379 (1988). Methods of producing suitable structurally modified peptides are well known in the art. In other embodiments, a peptide may be generated by expression in a recombinant host cell. In some preferred embodiments, the peptide may be glycosylated. Glycosylated peptides may be produced for example by expression in recombinant eukaryotic cells Aspects of the invention provide a nucleic acid encoding an isolated peptide described herein as described above and a vector comprising such a nucleic acid. Suitable vectors can be chosen or constructed, containing appropriate regulatory sequences, including promoter sequences, terminator fragments, polyadenylation sequences, enhancer sequences, marker genes and other sequences as appropriate. Preferably, the vector contains appropriate regulatory sequences to drive the expression of the nucleic acid in mammalian cells. A vector may also comprise sequences, such as origins of replication, promoter regions and selectable markers, which allow for its selection, expression and replication in bacterial hosts such as E. coli. Vectors may be plasmids, viral e.g. phage, or phagemid, as appropriate. For further details see, for example, Molecular Cloning: a Laboratory Manual: 3rd edition, Russell et al., 2001, Cold Spring Harbor Laboratory Press. Many known techniques and protocols for manipulation of nucleic acid, for example in preparation of nucleic acid constructs, mutagenesis, sequencing, introduction of DNA into cells and gene expression, are described in detail in Current Protocols in Molecular Biology, Ausubel et al. eds. John Wiley & Sons, 1992. A nucleic acid or vector as described herein may be introduced into a host cell. Another aspect of the invention provides a recombinant cell comprising a nucleic acid or vector that expresses a peptide as described above. A range of host cells suitable for the production of recombinant peptide are known in the art. Suitable host cells may include prokaryotic cells, in particular bacteria such as Escherichia coli and Lactococcus lactis and eukaryotic cells, including mammalian cells such as CHO and CHO-derived cell lines (Lec cells), HeLa, COS, HEK293 and HEK-EBNA cells, amphibian cells such as Xenopus oocytes, insect cells such as Trichoplusia ni, Sf9 and Sf21 and yeast cells, such as Pichia pastoris. Techniques for the introduction of nucleic acid into cells are well established in the art and any suitable technique may be employed, in accordance with the particular circumstances. For eukaryotic cells, suitable techniques may include calcium phosphate transfection, DEAE-Dextran, electroporation, liposome-mediated transfection and transduction using retrovirus or other virus, e.g. adenovirus, AAV, lentivirus or vaccinia. For bacterial cells, suitable techniques may include calcium chloride transformation, electroporation and transfection using bacteriophage. Marker genes such as antibiotic resistance or sensitivity genes may be used in identifying clones containing nucleic acid of interest, as is well-known in the art. The introduced nucleic acid may be on an extra-chromosomal vector within the cell or the nucleic acid may be integrated into the genome of the host cell. Integration may be promoted by inclusion of sequences within the nucleic acid or vector which promote recombination with the genome, in accordance with standard techniques. The introduction may be followed by expression of the nucleic acid to produce the encoded peptide. In some embodiments, host cells (which may include cells actually transformed although more likely the cells will be descendants of the transformed cells) may be cultured in vitro under conditions for expression of the nucleic acid, so that the encoded peptide is produced. When an inducible promoter is used, expression may require the activation of the inducible promoter. The expressed peptide may be isolated and/or purified, after production. This may be achieved using any convenient method known in the art. Techniques for the purification of recombinant polypeptides are well known in the art and include, for example HPLC, FPLC or affinity chromatography. In some embodiments, purification may be performed using an affinity tag on the polypeptide as described above. Another aspect of the invention provides a method of producing a peptide described herein comprising expressing a heterologous nucleic acid encoding the peptide in a host cell and optionally isolating and/or purifying the peptide thus produced. After production, the peptide may be investigated further, for example the pharmacological properties and/or activity may be determined. Methods and means of protein analysis are well-known in the art. "Heterologous" refers to a polypeptide or nucleic acid that is foreign to a particular biological system, such as a host cell, and is not naturally occurring in that system. A heterologous polypeptide or nucleic acid may be introduced to a biological system by artificial means, for example using recombinant techniques. For example, heterologous nucleic acid encoding a polypeptide may be inserted into a suitable expression construct which is in turn used to transform a host cell to produce the polypeptide. A heterologous polypeptide or nucleic acid may be synthetic or artificial or may exist in a different biological system, such as a different species or cell type. A recombinant polypeptide may be expressed from heterologous nucleic acid that has been introduced into a cell by artificial means, for example using recombinant techniques. A recombinant polypeptide may be identical to a polypeptide that is naturally present in the cell or may be different from the polypeptides that are naturally present in that cell. Also provided are pharmaceutical compositions comprising one or more isolated peptides described herein. For example, a composition may comprise two or more, three or more, four or more or five or more different peptides as described herein. A pharmaceutical composition may comprise, in addition to the peptide itself, a pharmaceutically acceptable excipient, carrier, buffer, stabilizer or other materials well known to those skilled in the art. The term “pharmaceutically acceptable” as used herein pertains to compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgement, suitable for use in contact with the tissues of a subject (e.g., human) without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio. Each carrier, excipient, etc. must also be “acceptable” in the sense of being compatible with the other ingredients of the formulation. The precise nature of the carrier or other material will depend on the route of administration, which may be by bolus, infusion, injection or any other suitable route, as discussed below. In some preferred embodiments, parenteral or oral routes of administration may be used. In some embodiments, the peptide may be provided in a lyophilised form for reconstitution prior to administration. For example, a lyophilised peptide may be re-constituted in sterile water and mixed with saline prior to administration to an individual. Alternative solvents may be used for peptides that are not water soluble. For parenteral, for example sub-cutaneous, intra-muscular or intra-venous administration, e.g. by injection, the pharmaceutical composition comprising a peptide described herein may be in the form of a parenterally acceptable aqueous solution which is pyrogen-free and has suitable pH, isotonicity and stability. Those of relevant skill in the art are well able to prepare suitable solutions using, for example, isotonic vehicles, such as Sodium Chloride Injection, Ringer's Injection, Lactated Ringer's Injection. Preservatives, stabilizers, buffers, antioxidants and/or other additives may be employed as required including buffers such as phosphate, citrate and other organic acids; antioxidants, such as ascorbic acid and methionine; preservatives (such as octadecyldimethylbenzyl ammonium chloride; hexamethonium chloride; benzalkonium chloride; benzethonium chloride; phenol, butyl or benzyl alcohol; alkyl parabens, such as methyl or propyl paraben; catechol; resorcinol; cyclohexanol; 3’-pentanol; and m-cresol); low molecular weight polypeptides; proteins, such as serum albumin, gelatin or immunoglobulins; hydrophilic polymers, such as polyvinylpyrrolidone; amino acids, such as glycine, glutamine, asparagines, histidine, arginine, or lysine; monosaccharides, disaccharides and other carbohydrates including glucose, mannose or dextrins; chelating agents, such as EDTA; sugars, such as sucrose, mannitol, trehalose or sorbitol; salt-forming counter-ions, such as sodium; metal complexes (e.g. Zn-protein complexes); and/or non-ionic surfactants, such as TWEEN^TM, PLURONICS^TM or polyethylene glycol (PEG). Suitable carriers, excipients, etc. can be found in standard pharmaceutical texts, for example, Remington’s Pharmaceutical Sciences, 18th edition, Mack Publishing Company, Easton, Pa., 1990. Pharmaceutical compositions and formulations may conveniently be presented in unit dosage form and may be prepared by any methods well known in the art of pharmacy. Such methods include the step of bringing into association the isolated peptide described herein with the carrier which constitutes one or more accessory ingredients. In general, the compositions are prepared by uniformly and intimately bringing into association the active compound with liquid carriers or finely divided solid carriers or both, and then if necessary shaping the product. A peptidyl therapeutic agent that comprises the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2, a fragment of said sequence or a variant of said sequence or fragment may be useful in methods for the treatment of a condition characterised by T cell mediated immune responses. For example, a method of treatment of a condition characterised by T cell proliferation may comprise administering a polypeptide comprising the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2, a fragment of said sequence or a variant of said sequence or fragment to an individual in need thereof. In some embodiments, the peptidyl therapeutic agent may be a polypeptide that comprises the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2 or a variant thereof. In other embodiments, the peptidyl therapeutic agent may be an isolated peptide as described above that comprises a fragment of the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 2 or a variant thereof, preferably a fragment of the amino acid sequence of SEQ ID NO: 15 or 16, or a variant thereof. For example, the isolated peptide may comprise the amino acid sequence of any one of SEQ ID NOs: 3 to 13. Variants and fragments of reference sequences such as SEQ ID NO: 1 and SEQ ID NO: 2 are described above. The peptidyl therapeutic agent may be a resistant to thrombin. For example, the peptidyl therapeutic agent may lack thrombin cleavage sites. Whilst the peptidyl therapeutic agent may be administered alone, for example for the inhibition of T cell proliferation or the treatment of conditions characterised by T cell immune responses, it will usually be administered in the form of a pharmaceutical composition, which may comprise at least one component in addition to the peptidyl therapeutic agent. Suitable components are described above. A condition characterised by T cell immune responses may be a disease, illness or medical condition characterised by undesirable, aberrant or pathological adaptive immune responses and/or excessive or aberrant proliferation or activation of CD4 and/or CD8 T cells relative to non-diseased controls. Conditions characterised by T cell immune responses may include auto-immune conditions, such as inflammatory bowel disease, such as Crohn’s disease and ulcerative colitis, rheumatoid arthritis; type 1 diabetes; systemic lupus erythematosus; psoriasis; psoriatic arthritis; vasculitis; Sjögren’s syndrome; eosinophilic gastrointestinal disorders (EGIDs), such as eosinophilic esophagitis; systemic sclerosis; idiopathic pulmonary fibrosis; polymyositis; dermatomyositis; pemphigus; vitiligo; alopecia areata; lupus nephritis; ankylosing spondylitis; Wiskott Aldrich syndrome; and T cell malignancies, such as T cell leukaemia and T cell lymphoma. Conditions characterised by T cell immune responses may also include allo-immune conditions, such as Graft vs Host Disease (GvHD) or transplant rejection. Conditions characterised by T cell immune responses may also include T cell malignancies, such as T cell lymphoma or T cell leukaemia. Treatment may include therapeutic and prophylactic or preventative treatment (e.g. treatment before the onset of a condition in an individual to reduce the risk of the condition occurring in the individual; delay its onset; or reduce its severity after onset). The method of treatment may comprise administering a peptidyl therapeutic agent described herein to an individual in need thereof. An individual suitable for treatment as described above may be a mammal, such as a rodent (e.g. a guinea pig, a hamster, a rat, a mouse), canine (e.g. a dog), feline (e.g. a cat), equine (e.g. a horse), a primate, simian (e.g. a monkey or ape), a monkey (e.g. marmoset, baboon), an ape (e.g. gorilla, chimpanzee, orang- utan, gibbon), or a human. In some preferred embodiments, the individual is a human. In other preferred embodiments, non-human mammals, especially mammals that are conventionally used as models for demonstrating therapeutic efficacy in humans (e.g. murine, primate, porcine, canine, or rabbit animals) may be employed. Administration is normally in a "therapeutically effective amount" or "prophylactically effective amount", this being sufficient to show benefit to a patient. Such benefit may be at least amelioration of pain in the patient. The actual amount administered, and rate and time-course of administration, will depend on the nature and severity of what is being treated, the particular mammal being treated, the clinical condition of the individual patient, the cause of the disorder, the site of delivery of the composition, the method of administration, the scheduling of administration and other factors known to medical practitioners. A composition may be administered alone or in combination with other treatments either simultaneously or sequentially dependent upon the circumstances of the individual to be treated. Treatments that may be administered in combination include but are not limited to immunosuppressants, such as corticosteroids, anti-proliferative agents (e.g. mycophenolate, mofetil, azathioprine, cyclophosphamide), calcineurin inhibitors (e.g. ciclosporin, tacrolimus); mTor inhibitors (e.g. sirolimus), and biological agents targeting specific pathways or cellular components of the immune system. Prescription of treatment, e.g. decisions on dosage etc, is within the responsibility of general practitioners and other medical doctors and may depend on the severity of the symptoms and/or progression of a disease being treated. Appropriate doses of therapeutic peptides and polypeptides are well known in the art (Ledermann J.A. et al. (1991) Int. J. Cancer 47: 659-664; Bagshawe K.D. et al. (1991) Antibody, Immunoconjugates and Radiopharmaceuticals 4: 915-922). Specific dosages may be indicated herein or in the Physician's Desk Reference (2003) as appropriate for the type of medicament being administered may be used. A therapeutically effective amount or suitable dose of a peptide or polypeptide described herein may be determined by comparing its in vitro activity and in vivo activity in an animal model. Methods for extrapolation of effective dosages in mice and other test animals to humans are known. The precise dose will depend upon a number of factors, including whether the peptide or polypeptide described herein is for prevention or for treatment, the size and location of the area to be treated, the precise nature of the peptide or polypeptide described herein and the nature of any detectable label or other molecule attached to the peptide or polypeptide described herein. A peptidyl therapeutic agent described herein may also be useful in in vitro assays, for example to identify patients likely to respond to treatment with the agent. A method may comprise; contacting a peptidyl therapeutic agent that comprises the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2, a fragment of said sequence or a variant of said sequence or fragment with a T cell and determining the effect of the agent on the T cell. For example, the effect of the agent on the activity, function, marker expression, activation and/or proliferation of the T cell may be determined. Suitable techniques for determining effects on T cells are well known in the art. The T cell may be contained in a sample obtained from an individual, such as a patient with a condition characterised by T cell immune responses. Inhibition of proliferation and/or activation of a T cell in the sample by the agent may be indicative that the individual is likely to respond to treatment. Other aspects and embodiments of the invention provide the aspects and embodiments described above with the term “comprising” replaced by the term “consisting of” and the aspects and embodiments described above with the term “comprising” replaced by the term ”consisting essentially of”. Reference to a nucleotide sequence as set out herein encompasses a DNA molecule with the specified sequence, and encompasses a RNA molecule with the specified sequence in which U is substituted for T, unless context requires otherwise. It is to be understood that the application discloses all combinations of any of the above aspects and embodiments described above with each other, unless the context demands otherwise. Similarly, the application discloses all combinations of the preferred and/or optional features either singly or together with any of the other aspects, unless the context demands otherwise. Modifications of the above embodiments, further embodiments and modifications thereof will be apparent to the skilled person on reading this disclosure, and as such, these are within the scope of the present invention. All documents and sequence database entries mentioned in this specification are incorporated herein by reference in their entirety for all purposes. “and/or” where used herein is to be taken as specific disclosure of each of the two specified features or components with or without the other. For example “A and/or B” is to be taken as specific disclosure of each of (i) A, (ii) B and (iii) A and B, just as if each is set out individually herein. Experimental Materials and Methods Materials. Monoclonal mouse FITC-, Alexa Fluor 700-, APC/Cy7-, Pacific Blue-, APC-, PE/Cy7-conjugated against human TCR (IP26), CD4 (OKT4), CD8 (SK1) and CD56 (HCD56) (Biolegend, London, UK), CD25 (2A3; BD Pharmingen, Oxford, UK), CD127 (eBioRDR5; eBioscience, Paisley, UK). Rabbit anti-human FoxP3 (Cell signalling technology,Hitchin, UK). Mouse anti-human F5 (Cambridge Biosciences, Cambridge, UK). B cell proliferation kit (R&D system, Abingdon, UK). BD CellFix (BD Biosciences, Oxford, UK). Proteinase inhibitor cocktail (Roche Diagnostics Ltd, West Sussex, UK). Native human F5, F5a, Thrombin, Dynabeads Human T reg Expander, PCR kits, CYBRgreen kit and CFSE kits (Thermofisher Scientific, Loughborough, UK). CD4+CD25 + CD127− T reg, CD8 T cell and B cell isolation kit (Miltenyi Biotec, Surrey, UK). Assay of FV plasma levels was performed using a human Factor V ELISA Kit (ab137976, Abcam, Cambridge, UK). Peptides were synthesised by Cambridge Research Biochemicals Limited, Cleveland, UK. > 90% purity was confirmed by HPLC / Mass Determination by Time of Flight. Mouse monoclonal IgG1 anti-human Factor V light chain, mouse IgG anti-human Factor V heavy chain, and mouse IgG1 anti Factor V B domain were from Haematologic Technologies Inc., VT, USA. Unless otherwise indicated, all reagents were from Sigma-Aldrich Company Ltd (Dorset, UK). Healthy volunteers and patients; Healthy donor blood samples were obtained from the NIHR Cambridge BioResource and leukapheresis samples from the National Health Service Blood and Transfusion services (NHSBT, Cambridge) with written informed consent of donors and approval of the National Research Ethics Committee and Health Research Authority. Peripheral blood cell isolation; Peripheral blood mononuclear cells (PBMCs) were isolated from blood by polysucrose density gradient centrifugation (Ficoll-Paque, GE Healthcare Life Sciences, UK). Cells were grown in RPMI media supplemented with 10% human AB serum. Cells were stained with a surface marker panel for 15 min at room temperature. Cells were then washed and fixed in BD CellFix and analysed promptly using a BD Fortessa flow cytometer (BD Biosciences, Oxford, UK). Neutrophils were isolated from blood by dextran sedimentation and discontinuous Percoll gradients. Analysis of neutrophil lysates was performed using liquid chromatography mass spectrometry (LC-MS)-based proteomics Stranded mRNA-Seq. CD4+CD25 + CD127− Tregs were isolated using a T reg isolation kit and cell purity was checked with the panel of surface markers described above. Total RNA was collected using RNeasy Plus Micro Kit (Qiagen, Manchester, UK). Sample sequencing libraries were prepared from 250 ng of total RNA using the TruSeq Stranded mRNA HT sample preparation kit (Illumina, Chesterford UK) according to the manufacturer’s instructions. Samples were individually indexed for pooling using a single index strategy. Libraries were quantified on a Bioanalyzer High Sensitivity DNA1000 chip (Agilent, Cheadle UK) and by qPCR using an NGS Library Quantification Kit (KAPA Biosystems, London UK) on an iCycler qPCR system (Bio-rad, Hemel Hempstead UK). Libraries were then normalised, pooled, diluted and denatured for sequencing on the NextSeq.500 (Illumina) according to the manufacturer’s instructions. Samples were pooled such that a minimum of 25 M unique clusters per sample was achieved. PhiX control library (Illumina) was spiked into the main library pool at 1% v/v for quality control purposes. Sequencing was performed using a high output flow cell with 2 × 75 cycles of sequencing providing 800 M paired end reads from 400 M unique clusters. The number of reads that were generated and used at the starting point of the analysis ranged from 27.5 to 33.5 million for each sample, and the range of sequence length was from 35 to 76 for all the samples. Reads were trimmed using TrimGalore v0.3.7 and mapped using STAR v2.4.0 h. Ensembl Homo_sapiens.GRCh38.dna.primary_assembly reference genome file was used to do the mapping of reads, using the annotated transcripts from the Ensembl Homo_sapiens.GRCh38.80 GTF file. The number of reads that map to a genomic feature was calculated using HTSeq v0.6.0 at gene level. Counting of mapped reads at isoform level was performed using RSEM v1.2.22. EdgeR computes effective library sizes using TMM normalization. The normalization factors account for sequencing depth and RNA composition. T cell in vitro expansion assay. T cons were isolated with the above-mentioned kit. Cells were stained with CFSE following the manufacturer’s instruction.5 × 104 labelled T cons were mixed with Dynabeads Human activator CD3/CD28 at cell-to-beads ratio of 2 to 1. Cells were collected and analysed using a BD Fortessa flow cytometer after 4 or 5 days. Suppression index was calculated as the ratio between decreased percentage of proliferation and the total percentage of proliferation of the cells. RT-PCR; 1 μg total RNA was amplified with F5 forward (5′- ACCACAATCTACCATTTCAGGACTT -3′); F5 reverse (5′- CGCCTCTGCTCACGAGTTAT -3′) and Foxp3 forward (5′- GCTGCAGCTCTCAACGGT -3′); Foxp3 reverse (5′- GGCAAACATGCGTGTGAAC -3′) using RT-PCR system following manufacture’s instruction ; the PCR product was visualized by 1% low melting temperature agarose gel in Tris-Acetate- EDTA buffer. Immunoblotting. Equal number of T regs and the CD4 enriched fraction isolated from the kit described above were collected and lysates prepared for SDS polyacrylamide gel electrophoresis and immunoblotting as previously described (Wang et al, 2018. Signals were detected by enhanced chemiluminesence using ECL (Thermo Scienific, Paisley, UK). Images were collected and analysed using Image Lab (Bio-Rad, Hemel Hempsted, UK). Expression of Factor V constructs; Native and mutated Factor V proteins were produced by Peak Proteins, Macclesfield, UK. Three constructs comprising (1) FV B domain ((aa710-1545), (2) full length FV (aa 1 - 2224) and (3) [R709A, R1018A, R1545A]FV aa1-2224 were sub-cloned into a proprietary vector for the HEK293-6E system. All sequences contained a C-terminal 6His tag to facilitate purification. Cells were transfected at a 500ml scale for each construct, media harvested 5-6 days after transfection and protein purified using a combination of Ni affinity and size exclusion chromatography and if required ion exchange. Purified proteins were analysed by reducing and non-reducing SDS-PAGE, A280 to determine concentration, size exclusion and mass spectrometry to confirm identity. Data analysis. Flow cytometry data were analysed using FlowJo (Tree Star, USA). Compensation controls were generated using CompBeads (BD Biosciences). Graphs and statistics were generated using GraphPad Prism software. Results were presented as mean ± s.e.m.as indicated. Differences between two groups were compared using two-tailed student’s t-test. Results To examine whether Factor V has any effect on T cell proliferation, CFSE-labelled conventional CD4+ T cells (Tcons) from healthy blood donors were stimulated in vitro and proliferation in the presence of Factor V and Factor Va was assessed by flow cytometry analysis of dye dilution. Factor V but not Factor Va suppressed proliferation of Tcons in a concentration dependent manner (Figure 2). Factor V suppressed proliferation of T conventional (Tcon) cells stimulated by anti-CD3 coated beads. Tcon are incubated with a fluorescent dye (Figure 2). This effect is highly reproducible and similar to that seen by incubating Tcon with Tregs. The effect is not seen if factor V is activated. To confirm that the suppressive effect was mediated by full length uncleaved Factor V, we generated recombinant proteins from three Factor V constructs: (1) Factor V(738-1573)-6His (the B domain of Factor V); (2) Factor V-6His (full length Factor V); (3) Factor V R709A, R1018A, R1545A-6His (full length Factor V with Arg thrombin cleavage sites mutated). Full length recombinant Factor V, but not a recombinant B domain, inhibited CD4 cell proliferation, and this effect was prevented by thrombin, and enhanced by the thrombin inhibitor hirudin (Figure 3). Thrombin did not increase proliferation in the absence of Factor V. A cleavage resistant recombinant Factor V was found to be a potent inhibitor of CD4 cell proliferation. To test whether the effect of Factor V was specific for CD4 cells, recombinant full-length Factor V and a cleavage resistant recombinant Factor V were shown to suppress CD8 cell proliferation, but not B cell proliferation (Figure 4). Peptides spanning the cleavage sites of Factor V, and peptides derived from the repetitive sequences of the B domain were generated. The specific peptides are shown in Table 1. Peptide 1 and Peptide 2, spanning the first cleavage site of Factor V suppressed T cell proliferation in three of three experiments, with Peptide 2 having a more marked effect in two of the experiments. Peptides 4 and 6 also suppressed T cell proliferation in some experiments, but the effect was less marked. Peptides 7 and 8 were derived from repetitive sequences in the B domain that are enriched with SPDLS and SPELS motifs. These peptides also suppressed T cell proliferation, with the longer peptide having a more marked effect (Figure 7). Peptide 1 (P1; SEQ ID NO: 3) – aa 700 to aa 718 NRLAAALGIRSFRNSSLNQ – sequence spanning Arg709 Peptide 2 (P2; SEQ ID NO: 4) – aa 700 to aa 718 NRLAAALGIKSFRNSSLNQ – Peptide 1 with Arg709 replaced by Lys Peptide 3 (P3; SEQ ID NO: 5) – aa 1009 to aa 1027 HTHHAPLSPRTFHPLRSEA – sequence spanning Arg1018 Peptide 4 (P4; SEQ ID NO: 6) – aa 1009 to aa 1027 HTHHAPLSPKTFHPLRSEA – Peptide 3 with Arg1018 replaced by Lys Peptide 5 (P5; SEQ ID NO: 7) – aa 1536 to aa 1555 PDNIAAWYLRSNNGNRRNY – sequence spanning Arg1545 Peptide 6 (P6; SEQ ID NO: 8) – aa 1536 to aa 1555 PDNIAAWYLKSNNGNRRNY – Peptide 5 with Arg1019 replaced by Lys Peptide 7 (P7; SEQ ID NO: 12) – aa 1300 to aa 1319 GQMPISPDLSHTTLSPDLSH Peptide 8 (P10; SEQ ID NO: 13) – aa 1296 to aa 1330 SPALGQMPISPDLSHTTLSPDLSHTTLSLDLSQTN Table 1

Reference Sequences 0001 mfpgcprlwv lvvlgtswvg wgsqgteaaq lrqfyvaaqg iswsyrpept nsslnlsvts 0061 fkkivyreye pyfkkekpqs tisgllgptl yaevgdiikv hfknkadkpl sihpqgirys 121 klsegasyld htfpaekmdd avapgreyty ewsisedsgp thddppclth iyyshenlie 181 dfnsgligpl lickkgtlte ggtqktfdkq ivllfavfde skswsqsssl mytvngyvng 241 tmpditvcah dhiswhllgm ssgpelfsih fngqvleqnh hkvsaitlvs atsttanmtv 301 gpegkwiiss ltpkhlqagm qayidikncp kktrnlkkit reqrrhmkrw eyfiaaeevi 361 wdyapvipan mdkkyrsqhl dnfsnqigkh ykkvmytqye desftkhtvn pnmkedgilg 421 piiraqvrdt lkivfknmas rpysiyphgv tfspyedevn ssftsgrnnt miravqpget 481 ytykwnilef deptendaqc ltrpyysdvd imrdiasgli glllicksrs ldrrgiqraa 541 dieqqavfav fdenkswyle dninkfcenp devkrddpkf yesnimstin gyvpesittl 601 gfcfddtvqw hfcsvgtqne iltihftghs fiygkrhedt ltlfpmrges vtvtmdnvgt 661 wmltsmnssp rskklrlkfr dvkcipddde dsyeifeppe stvmatrkmh drlepedees 721 dadydyqnrl aaalgirsfr nsslnqeeee fnltalalen gtefvssntd iivgsnyssp 781 sniskftvnn laepqkapsh qqattagspl rhligknsvl nsstaehssp ysedpiedpl 841 qpdvtgirll slgagefksq ehakhkgpkv erdqaakhrf swmkllahkv grhlsqdtgs 901 psgmrpwedl psqdtgspsr mrpwkdppsd llllkqsnss kilvgrwhla sekgsyeiiq 961 dtdedtavnn wlispqnasr awgestplan kpgkqsghpk fprvrhkslq vrqdggksrl 1021 kksqfliktr kkkkekhthh aplsprtfhp lrseayntfs errlkhslvl hksnetslpt 1081 dlnqtlpsmd fgwiaslpdh nqnssndtgq ascppglyqt vppeehyqtf piqdpdqmhs 1141 tsdpshrsss pelsemleyd rshksfptdi sqmspssehe vwqtvispdl sqvtlspels 1201 qtnlspdlsh ttlspeliqr nlspalgqmp ispdlshttl spdlshttls ldlsqtnlsp 1261 elsqtnlspa lgqmplspdl shttlsldfs qtnlspelsh mtlspelsqt nlspalgqmp 1321 ispdlshttl sldfsqtnls pelsqtnlsp algqmplspd pshttlsldl sqtnlspels 1381 qtnlspdlse mplfadlsqi pltpdldqmt lspdlgetdl spnfgqmsls pdlsqvtlsp 1441 disdttllpd lsqispppdl dqifypsess qslllqefne sfpypdlgqm pspssptlnd 1501 tflskefnpl vivglskdgt dyieiipkee vqsseddyae idyvpyddpy ktdvrtnins 1561 srdpdniaaw ylrsnngnrr nyyiaaeeis wdysefvqre tdiedsddip edttykkvvf 1621 rkyldstftk rdprgeyeeh lgilgpiira evddviqvrf knlasrpysl hahglsyeks 1681 segktyedds pewfkednav qpnssytyvw hatersgpes pgsacraway ysavnpekdi 1741 hsgligplli cqkgilhkds nmpmdmrefv llfmtfdekk swyyekksrs swrltssemk 1801 kshefhaing miyslpglkm yeqewvrlhl lniggsqdih vvhfhgqtll engnkqhqlg 1861 vwpllpgsfk tlemkaskpg wwllntevge nqragmqtpf limdrdcrmp mglstgiisd 1921 sqikaseflg yweprlarln nggsynawsv eklaaefask pwiqvdmqke viitgiqtqg 1981 akhylkscyt tefyvayssn qinwqifkgn strnvmyfng nsdastiken qfdppivary 2041 irisptrayn rptlrlelqg cevngcstpl gmengkienk qitassfkks wwgdywepfr 2101 arlnaqgrvn awqakannnk qwleidllki kkitaiitqg ckslssemyv ksytihyseq 2161 gvewkpyrlk ssmvdkifeg ntntkghvkn ffnppiisrf irvipktwnq sialrlelfg 2221 cdiy SEQ ID NO: 1 (signal sequence underlined; full length FV protein), wherein R residues corresponding to positions 709, 1018 and 1545 of the mature full length FV protein in bold. 0001 mfpgcprlwv lvvlgtswvg wgsqgteaaq lrqfyvaaqg iswsyrpept nsslnlsvts 0061 fkkivyreye pyfkkekpqs tisgllgptl yaevgdiikv hfknkadkpl sihpqgirys 121 klsegasyld htfpaekmdd avapgreyty ewsisedsgp thddppclth iyyshenlie 181 dfnsgligpl lickkgtlte ggtqktfdkq ivllfavfde skswsqsssl mytvngyvng 241 tmpditvcah dhiswhllgm ssgpelfsih fngqvleqnh hkvsaitlvs atsttanmtv 301 gpegkwiiss ltpkhlqagm qayidikncp kktrnlkkit reqrrhmkrw eyfiaaeevi 361 wdyapvipan mdkkyrsqhl dnfsnqigkh ykkvmytqye desftkhtvn pnmkedgilg 421 piiraqvrdt lkivfknmas rpysiyphgv tfspyedevn ssftsgrnnt miravqpget 481 ytykwnilef deptendaqc ltrpyysdvd imrdiasgli glllicksrs ldrrgiqraa 541 dieqqavfav fdenkswyle dninkfcenp devkrddpkf yesnimstin gyvpesittl 601 gfcfddtvqw hfcsvgtqne iltihftghs fiygkrhedt ltlfpmrges vtvtmdnvgt 661 wmltsmnssp rskklrlkfr dvkcipddde dsyeifeppe stvmatrkmh drlepedees 721 dadydyqnrl aaalgix₁sfr nsslnqeeee fnltalalen gtefvssntd iivgsnyssp 781 sniskftvnn laepqkapsh qqattagspl rhligknsvl nsstaehssp ysedpiedpl 841 qpdvtgirll slgagefksq ehakhkgpkv erdqaakhrf swmkllahkv grhlsqdtgs 901 psgmrpwedl psqdtgspsr mrpwkdppsd llllkqsnss kilvgrwhla sekgsyeiiq 961 dtdedtavnn wlispqnasr awgestplan kpgkqsghpk fprvrhkslq vrqdggksrl 1021 kksqfliktr kkkkekhthh aplspx2tfhp lrseayntfs errlkhslvl hksnetslpt 1081 dlnqtlpsmd fgwiaslpdh nqnssndtgq ascppglyqt vppeehyqtf piqdpdqmhs 1141 tsdpshrsss pelsemleyd rshksfptdi sqmspssehe vwqtvispdl sqvtlspels 1201 qtnlspdlsh ttlspeliqr nlspalgqmp ispdlshttl spdlshttls ldlsqtnlsp 1261 elsqtnlspa lgqmplspdl shttlsldfs qtnlspelsh mtlspelsqt nlspalgqmp 1321 ispdlshttl sldfsqtnls pelsqtnlsp algqmplspd pshttlsldl sqtnlspels 1381 qtnlspdlse mplfadlsqi pltpdldqmt lspdlgetdl spnfgqmsls pdlsqvtlsp 1441 disdttllpd lsqispppdl dqifypsess qslllqefne sfpypdlgqm pspssptlnd 1501 tflskefnpl vivglskdgt dyieiipkee vqsseddyae idyvpyddpy ktdvrtnins 1561 srdpdniaaw ylx3snngnrr nyyiaaeeis wdysefvqre tdiedsddip edttykkvvf 1621 rkyldstftk rdprgeyeeh lgilgpiira evddviqvrf knlasrpysl hahglsyeks 1681 segktyedds pewfkednav qpnssytyvw hatersgpes pgsacraway ysavnpekdi 1741 hsgligplli cqkgilhkds nmpmdmrefv llfmtfdekk swyyekksrs swrltssemk 1801 kshefhaing miyslpglkm yeqewvrlhl lniggsqdih vvhfhgqtll engnkqhqlg 1861 vwpllpgsfk tlemkaskpg wwllntevge nqragmqtpf limdrdcrmp mglstgiisd 1921 sqikaseflg yweprlarln nggsynawsv eklaaefask pwiqvdmqke viitgiqtqg 1981 akhylkscyt tefyvayssn qinwqifkgn strnvmyfng nsdastiken qfdppivary 2041 irisptrayn rptlrlelqg cevngcstpl gmengkienk qitassfkks wwgdywepfr 2101 arlnaqgrvn awqakannnk qwleidllki kkitaiitqg ckslssemyv ksytihyseq 2161 gvewkpyrlk ssmvdkifeg ntntkghvkn ffnppiisrf irvipktwnq sialrlelfg 2221 cdiy SEQ ID NO: 2 (signal sequence underlined), wherein residues X1, X2 and X3 (corresponding to positions 709, 1018 and 1545 of the mature full length FV protein) are independently not R, preferably wherein residues X1, X2 and X3 are independently not R or Q, most preferably wherein residues X1, X2 and X3 are independently A or K. NRLAAALGIRSFRNSSLNQ SEQ ID NO: 3 NRLAAALGIKSFRNSSLNQ SEQ ID NO: 4 HTHHAPLSPRTFHPLRSEA SEQ ID NO: 5 HTHHAPLSPKTFHPLRSEA SEQ ID NO: 6 PDNIAAWYLRSNNGNRRNY SEQ ID NO: 7 PDNIAAWYLKSNNGNRRNY SEQ ID NO: 8 NRLAAALGIX1SFRNSSLNQ where X1 is any residue other than R, preferably A or K. SEQ ID NO: 9 HTHHAPLSPX₂TFHPLRSEA where X2 is any residue other than R, preferably A or K. SEQ ID NO: 10 PDNIAAWYLX₃SNNGNRRNY where X₃ is any residue other than R, preferably A or K. SEQ ID NO: 11 GQMPISPDLSHTTLSPDLSH SEQ ID NO: 12 SPALGQMPISPDLSHTTLSPDLSHTTLSLDLSQTN SEQ ID NO: 13 SPELSEMLEYDRSHKSFPTDISQMSPSSEHEVWQTVISPDLSQVTLSPELSQTNLSPDLSHTTLSPELIQRNLS PALGQMPISPDLSHTTLSPDLSHTTLSLDLSQTNLSPELSQTNLSPALGQMPLSPDLSHTTLSLDFSQTNLSPE LSHMTLSPELSQTNLSPALGQMPISPDLSHTTLSLDFSQTNLSPELSQTNLSPALGQMPLSPDPSHTTLSLDLS QTNLSPELSQTNLSPDLSEMPLFADLSQIPLTPDLDQMTLSPDLGETDLSPNFGQMSLSPDLS SEQ ID NO:14 NRLAAALGIRSFRNSSLNQEEEEFNLTALALENGTEFVSSNTDIIVGSNYSSPSNISKFTVNNLAEPQKAPSHQ QATTAGSPLRHLIGKNSVLNSSTAEHSSPYSEDPIEDPLQPDVTGIRLLSLGAGEFKSQEHAKHKGPKVERDQA AKHRFSWMKLLAHKVGRHLSQDTGSPSGMRPWEDLPSQDTGSPSRMRPWKDPPSDLLLLKQSNSSKILVGRWHL ASEKGSYEIIQDTDEDTAVNNWLISPQNASRAWGESTPLANKPGKQSGHPKFPRVRHKSLQVRQDGGKSRLKKS QFLIKTRKKKKEKHTHHAPLSPRTFHPLRSEAYNTFSERRLKHSLVLHKSNETSLPTDLNQTLPSMDFGWIASL PDHNQNSSNDTGQASCPPGLYQTVPPEEHYQTFPIQDPDQMHSTSDPSHRSSSPELSEMLEYDRSHKSFPTDIS QMSPSSEHEVWQTVISPDLSQVTLSPELSQTNLSPDLSHTTLSPELIQRNLSPALGQMPISPDLSHTTLSPDLS HTTLSLDLSQTNLSPELSQTNLSPALGQMPLSPDLSHTTLSLDFSQTNLSPELSHMTLSPELSQTNLSPALGQM PISPDLSHTTLSLDFSQTNLSPELSQTNLSPALGQMPLSPDPSHTTLSLDLSQTNLSPELSQTNLSPDLSEMPL FADLSQIPLTPDLDQMTLSPDLGETDLSPNFGQMSLSPDLSQVTLSPDISDTTLLPDLSQISPPPDLDQIFYPS ESSQSLLLQEFNESFPYPDLGQMPSPSSPTLNDTFLSKEFNPLVIVGLSKDGTDYIEIIPKEEVQSSEDDYAEI DYVPYDDPYKTDVRTNINSSRDPDNIAAWYLRSNNGNRRNY SEQ ID NO: 15 NRLAAALGIX₁SFRNSSLNQEEEEFNLTALALENGTEFVSSNTDIIVGSNYSSPSNISKFTVNNLAEPQKAPSH QQATTAGSPLRHLIGKNSVLNSSTAEHSSPYSEDPIEDPLQPDVTGIRLLSLGAGEFKSQEHAKHKGPKVERDQ AAKHRFSWMKLLAHKVGRHLSQDTGSPSGMRPWEDLPSQDTGSPSRMRPWKDPPSDLLLLKQSNSSKILVGRWH LASEKGSYEIIQDTDEDTAVNNWLISPQNASRAWGESTPLANKPGKQSGHPKFPRVRHKSLQVRQDGGKSRLKK SQFLIKTRKKKKEKHTHHAPLSPX₂TFHPLRSEAYNTFSERRLKHSLVLHKSNETSLPTDLNQTLPSMDFGWIA SLPDHNQNSSNDTGQASCPPGLYQTVPPEEHYQTFPIQDPDQMHSTSDPSHRSSSPELSEMLEYDRSHKSFPTD ISQMSPSSEHEVWQTVISPDLSQVTLSPELSQTNLSPDLSHTTLSPELIQRNLSPALGQMPISPDLSHTTLSPD LSHTTLSLDLSQTNLSPELSQTNLSPALGQMPLSPDLSHTTLSLDFSQTNLSPELSHMTLSPELSQTNLSPALG QMPISPDLSHTTLSLDFSQTNLSPELSQTNLSPALGQMPLSPDPSHTTLSLDLSQTNLSPELSQTNLSPDLSEM PLFADLSQIPLTPDLDQMTLSPDLGETDLSPNFGQMSLSPDLSQVTLSPDISDTTLLPDLSQISPPPDLDQIFY PSESSQSLLLQEFNESFPYPDLGQMPSPSSPTLNDTFLSKEFNPLVIVGLSKDGTDYIEIIPKEEVQSSEDDYA EIDYVPYDDPYKTDVRTNINSSRDPDNIAAWYLX₃SNNGNRRNY SEQ ID NO: 16 wherein residues X1, X2 and X3 (corresponding to positions 709, 1018 and 1545 of the mature full length FV protein) are independently not R, preferably wherein residues X1, X2 and X3 are independently not R or Q, most preferably wherein residues X1, X2 and X3 are independently A or K.

Claims

Claims: 1. An isolated peptide comprising a fragment of the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2 or a variant thereof.

2. An isolated peptide according to claim 1 comprising a fragment of SEQ ID NO: 15 or SEQ ID NO: 16 or a variant thereof.

3. An isolated peptide according to claim 1 or 2 which inhibits T cell proliferation and/or activation.

4. An isolated peptide according to one of the preceding claims consisting of 100 or fewer amino acids.

5. An isolated peptide according to any one of the preceding claims comprising the amino acid sequence of any one of SEQ ID NOs: 3 to 11 or a variant thereof.

6. An isolated peptide according to any one of claims 1 to 4 comprising a fragment of SEQ ID NO: 14 or a variant thereof.

7. An isolated peptide according to claim 6 comprising the amino acid sequence of any one of SEQ ID NOs: 12 to 13 or a variant thereof.

8. An isolated peptide according to any one of the preceding claims wherein peptide lacks thrombin cleavage sites.

9. A nucleic acid encoding an isolated peptide according to any one of the preceding claims.

10. A vector comprising a nucleic acid according to claim 9.

11. A recombinant cell comprising a nucleic acid according to claim 9 or a vector according to claim 10.

12. A pharmaceutical composition comprising (i) one or more isolated peptides according to any one of claims 1 to 8 and/or (ii) an isolated polypeptide comprising the amino acid sequence of SEQ ID NO: 2 or a variant thereof; and a pharmaceutically acceptable excipient.

13. A method of producing a pharmaceutical composition comprising admixing one or more isolated peptides of any one of claims 1 to 8 and/or (ii) an isolated polypeptide comprising the amino acid sequence of SEQ ID NO: 2 or a variant thereof; with a pharmaceutically acceptable excipient.

14. An isolated peptide according to any one of claims 1 to 8 and/or an isolated polypeptide comprising the amino acid sequence of SEQ ID NO: 2 or a variant thereof for use in the treatment of the human or animal body.

15. A method of treatment of a condition characterised by T cell immune responses comprising administering to an individual in need thereof a peptidyl therapeutic agent that comprises the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2, a fragment of said sequence or a variant of said sequence or fragment..

16. A peptidyl therapeutic agent that comprises the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2, a fragment of said sequence or a variant of said sequence or fragment for use in the treatment of a condition characterised by T cell immune responses.

17. Use of a peptidyl therapeutic agent that comprises the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2, a fragment of said sequence or a variant of said sequence or fragment for the manufacture of a medicament for the treatment of a condition characterised by T cell immune responses.

18. A method according to claim 15, peptidyl therapeutic agent for use according to claim 16 or use according to claim 17, wherein the peptidyl therapeutic agent comprises the amino acid sequence of any one of SEQ ID NOs: 3 to 13 or a variant thereof.

19. A method according to claim 15 or claim 18, peptidyl therapeutic agent for use according to claim 16 or claim 18 or use according to claim 17 or claim 18, wherein the peptidyl therapeutic agent comprises an isolated peptide according to any one of claims 1 to 8 or a pharmaceutical composition according to claim 12.

20. A method according to claim 15, claim 18 or claim 19, peptidyl therapeutic agent for use according to claim 16, claim 18 or claim 19 or use according to claim 17, claim 18 or claim 19, wherein the condition characterised by T cell immune responses is a T cell malignancy,

21. A method according to claim 20, peptidyl therapeutic agent for use according to claim 20 or use according to claim 20, wherein the T cell malignancy is T cell lymphoma or T cell leukaemia

22. A method according to claim 15, claim 18 or claim 19, peptidyl therapeutic agent for use according to claim 16, claim 18 or claim 19 or use according to claim 17, claim 18 or claim 19, wherein the condition characterised by T cell immune responses is an auto-immune condition.

23. A method according to claim 22, peptidyl therapeutic agent for use according to claim 22 or use according to claim 22, wherein the auto-immune condition is selected from inflammatory bowel disease, rheumatoid arthritis; type 1 diabetes; systemic lupus erythematosus; psoriasis; psoriatic arthritis; vasculitis; Sjögren’s syndrome, an eosinophilic gastrointestinal disorder (EGID), systemic sclerosis, idiopathic pulmonary fibrosis, polymyositis and dermatomyositis, pemphigus, vitiligo, alopecia areata, lupus nephritis, ankylosing spondylitis and Wiskott Aldrich syndrome. .

24. A method according to claim 15, claim 18 or claim 19, peptidyl therapeutic agent for use according to claim 16, claim 18 or claim 19 or use according to claim 17, claim 18 or claim 19, wherein the condition characterised by T cell immune responses is an allo-immune condition.

25. A method according to claim 24, peptidyl therapeutic agent for use according to claim 24 or use according to claim 24, wherein the allo-immune condition selected from transplant rejection and GvHD.