Tcr with high affinity and specificity specific for preproinsulin peptide alwgpdpaaa bound to hla-a2*02

HK40138642APending Publication Date: 2026-10-09IMMUNOCORE LTD
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Patent Information

Application Number
HK62026126323
Authority / Receiving Office
HK · HK
Patent Type
Applications
Current Assignee / Owner
Priority Date
2023-04-28
Filing Date
2026-07-17
Publication Date
2026-10-09
Estimated Expiration
2044-04-25

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Abstract

The present invention relates to binding molecules comprising a peptide-major histocompatibility complex (pMHC)-binding domain which binds to a ALWGPDPAAA (SEQ ID NO: 1) peptide (derived from human pre-pro insulin (PPI) protein) presented as a peptide-HLA-A*02 complex. Said binding molecules may comprise CDR sequences embedded within a framework sequence. The CDRs and framework sequences may correspond to a T cell receptor (TCR) variable domain and may further comprise non-natural mutations relative to a native TCR variable domain. The binding molecules of the invention have high affinity and high specificity for the ALWGPDPAAA (SEQ ID NO: 1)-HLA-A*02 complex. The binding molecules may further comprise an immune suppressor and / or a half-life extending domain. Such binding molecules are particularly useful in the development of soluble immunotherapeutic reagents for the treatment of autoimmune diseases, such as diabetes.
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Description

CN Title High Affinity and Specificity TCR Targeting the Proinsulin Peptide ALWGPDPAAA with HLA-A2*02 CN Abstract This invention relates to a binding molecule comprising a peptide-major histocompatibility complex (pMHC) binding domain that binds to the ALWGPDPAAA (SEQ ID NO: 1) peptide (derived from human proinsulin (PPI) protein) presented as a peptide-HLA-A*02 complex. The binding molecule may contain a CDR sequence embedded within a frame sequence. The CDR and frame sequence may correspond to a T cell receptor (TCR) variable domain and may further contain a non-natural mutation relative to the native TCR variable domain. The binding molecule of this invention exhibits high affinity and high specificity for the ALWGPDPAAA (SEQ ID NO: 1)-HLA-A*02 complex. The binding molecule may further contain an immunosuppressive factor and / or a half-life extension domain. Such binding molecules are particularly useful for developing soluble immunotherapeutic agents for the treatment of autoimmune diseases such as diabetes. Abstract

Claims

Claims:1 . A binding molecule comprising a peptide-major histocompatibility complex (pMHC)-binding domain that has the property of binding to a ALWGPDAAA (SEQ ID NO: 1) HLA-A*02 complex, wherein the pMHC-binding domain comprises (i) an alpha chain, comprising at least a TCR alpha chain variable domain, and (ii) a beta chain, comprising at least a TCR beta chain variable domain, wherein(a) the TCR alpha chain variable domain comprises a CDR1 , a CDR2 and a CDR3 comprising the following sequences:CDR1 - DKHSQG (SEQ ID NO: 23), optionally with one, two or three mutations therein, CDR2 - IYSQGD (SEQ ID NO: 27), optionally with one, two or three mutations therein, CDR3 - AVRGNEKLT (SEQ ID NO: 7), optionally with one, two or three mutations therein, and / or(b) the TCR beta chain variable domain comprises a CDR1 , a CDR2 and a CDR3 comprising the following sequences:CDR1 - LQHSY (SEQ ID NO: 35), optionally with one, two or three mutations therein, CDR2 - SVGVGF (SEQ ID NO: 29), optionally with one, two or three mutations therein, CDR3 - ASAYMTGELF (SEQ ID NO: 30), optionally with one, two or three mutations therein.

2. The binding molecule of claim 1 , wherein the mutation(s) in the TCR alpha chain variable domain CDRs are selected from K28R (CDR1), H29G (CDR1), G32S (CDR1) and Q53N (CDR2), numbered according to SEQ ID NO: 26; and / or the mutation(s) in the beta chain CDRs are selected from L27M (CDR1), Q28N (CDR1), S30N (CDR1), V52A (CDR2), F54I (CDR2) and A104S (CDR3), numbered according to SEQ ID NO: 74.

3. The binding molecule of claim 1 or claim 2, comprising one of the following combinations of TCR alpha chain variable domain CDRs and TCR beta chain variable domain CDRs:(a) alpha chain CDR1 , CDR2 and CDR3 amino acid sequences of DRGSQS (SEQ ID NO: 5), IYSNGD (SEQ ID NO: 6) and AVRGNEKLT (SEQ ID NO: 7), respectively, and beta chain CDR1 , CDR2 and CDR3 amino acid sequences of MNHNY (SEQ ID NO: 15), SVGAGI (SEQ ID NO: 16) and ASSYMTGELF (SEQ ID NO: 17), respectively;(b) alpha chain CDR1 , CDR2 and CDR3 amino acid sequences of DKHSQG (SEQ ID NO: 23), IYSNGD (SEQ ID NO: 6) and AVRGNEKLT (SEQ ID NO: 7), respectively, and beta chain CDR1 , CDR2 and CDR3 amino acid sequences of MNHSY (SEQ ID NO: 28), SVGVGF (SEQ ID NO: 29) and ASAYMTGELF (SEQ ID NO: 30), respectively;(c) alpha chain CDR1 , CDR2 and CDR3 amino acid sequences of DKHSQG (SEQ ID NO: 23), IYSNGD (SEQ ID NO: 6) and AVRGNEKLT (SEQ ID NO: 7), respectively, and beta chain CDR1 , CDR2 and CDR3 amino acid sequences of MQHSY (SEQ ID NO: 32), SVGVGF (SEQ ID NO: 29) and ASAYMTGELF (SEQ ID NO: 30), respectively; or(d) alpha chain CDR1 , CDR2 and CDR3 amino acid sequences of DKHSQG (SEQ ID NO: 23), IYSQGD (SEQ ID NO: 27) and AVRGNEKLT (SEQ ID NO: 7), respectively, and beta chain CDR1 , CDR2 and CDR3 amino acid sequences of LQHSY (SEQ ID NO: 35), SVGVGF (SEQ ID NO: 29) and ASAYMTGELF (SEQ ID NO: 30), respectively.

4. The binding molecule of any preceding claim, wherein the TOR alpha chain variable domain comprises framework regions, FR1 , FR2, FR3 and FR4, comprising the following sequences:FR1 - AKEVEQNSGPLSVPEGAIASLQCTYS (SEQ ID NO: 25), optionally with one, two or three mutations therein,FR2 - FFWYRQYSGKSPELIMS (SEQ ID NO: 9), optionally with one, two or three mutations therein,FR3 - KEDGRFTAQLNKASQYVSLLIRDSQPSDSATYLC (SEQ ID NO: 10), optionally with one, two or three mutations therein,FR4 - FGTGTRLTIIP (SEQ ID NO: 11), optionally with one, two or three mutations therein, and / or the TOR beta chain variable domain comprises framework regions, FR1 , FR2, FR3 and FR4, comprising the following sequences:FR1 - NAGVTQTPKFRILKIGQSMTLQCAQD (SEQ ID NO: 18), optionally with one, two or three mutations therein,FR2 - MYWYRQDPGMGLKPIYY (SEQ ID NO: 19), optionally with one, two or three mutations therein,FR3 - TDKGEVPQGYQVSRSTTEDFPLRLESAAPSQTSVYFC (SEQ ID NO: 75), optionally with one, two or three mutations therein,FR4 - FGEGSRLTVL (SEQ ID NO: 21), optionally with one, two or three mutations therein.

5. The binding molecule of claim 4, wherein the mutation(s) in the TOR alpha chain variable domain framework regions are selected from A1Q and Q22N, numbered according to SEQ ID NO: 26, and / or the mutation(s) in the TOR beta chain variable domain framework regions are selected from Q62N, Q62E, Q62D and Q65N, numbered according to SEQ ID NO: 74.

6. The binding molecule of any preceding claim, wherein(a) the TOR alpha chain variable domain comprises an amino acid sequence provided in any one of SEQ ID NOs: 3, 22, 24 and 26, or an amino acid sequence having at least 80%, at least 90%, at least 95% or at least 98% identity to any one of SEQ ID NOs: 3, 22, 24 and 26, and(b) the TOR beta chain variable domain comprises an amino acid sequence provided in any one of SEQ ID NOs:13, 68, 31 , 34, 74, 76 and 78, or an amino acid sequence having at least 80%, at least 90%, at least 95% or at least 98% identity to any one of SEQ ID NOs: 13, 68, 31 , 34, 74, 76 and 78.

7. The binding molecule of any one of the preceding claims, comprising one of the following combinations of TCR alpha and beta chain variable domains:(a) a TCR alpha chain variable domain comprising the amino acid sequence provided in SEQ ID NO: 22 and a TCR beta chain variable domain comprising the amino acid sequence provided in SEQ ID NO: 68;(b) a TCR alpha chain variable domain comprising the amino acid sequence provided in SEQ ID NO: 24 and a TCR beta chain variable domain comprising the amino acid sequence provided in SEQ ID NO: 31 ;(c) a TCR alpha chain variable domain comprising the amino acid sequence provided in SEQ ID NO: 26 and a TCR beta chain variable domain comprising the amino acid sequence provided in SEQ ID NO: 34;(d) a TCR alpha chain variable domain comprising the amino acid sequence provided in SEQ ID NO: 26 and a TCR beta chain variable domain comprising the amino acid sequence provided in SEQ ID NO: 74;(e) a TCR alpha chain variable domain comprising the amino acid sequence provided in SEQ ID NO: 26 and a TCR beta chain variable domain comprising the amino acid sequence provided in SEQ ID NO: 76; or(f) a TCR alpha chain variable domain comprising the amino acid sequence provided in SEQ ID NO: 26 and a TCR beta chain variable domain comprising the amino acid sequence provided in SEQ ID NO: 78.

8. The binding molecule of any preceding claim, wherein the TCR alpha chain variable domain comprises the amino acid sequence of SEQ ID NO: 26 and the TCR beta chain variable domain comprises the amino acid sequence of SEQ ID NO: 74.

9. The binding molecule of any preceding claim, wherein the alpha chain comprises a TCR alpha chain constant domain and / or the beta chain comprises a TCR beta chain constant domain.

10. The binding molecule of claim 9, wherein a non-native disulphide bond links a residue of the TCR alpha chain constant domain to a residue of the TCR beta chain constant domain.11 . The binding molecule of claim 9 or claim 10, wherein the TCR alpha chain constant domain comprises the amino acid sequence provided in SEQ ID NO: 37, or an amino acid sequence having at least 80%, at least 90%, at least 95% or at least 98% identity to SEQ ID NO: 37; and / or the TCR beta chain constant domain comprises the amino acid sequence provided in SEQ ID NO: 39, or an amino acid sequence having at least 80%, at least 90%, at least 95% or at least 98% identity to SEQ ID NO: 39.

12. The binding molecule of any preceding claim, which comprises two or more polypeptide chains, wherein the alpha chain and the beta chain are comprised in separate polypeptide chains.

13. The binding molecule of any preceding claim, wherein(a) the alpha chain comprises the amino acid sequence provided in any one of SEQ ID NOs: 2, 70, 36, and 40, or an amino acid sequence that has at least 90%, at least 95%, or at least 98% identity to an amino acid sequence provided in any one of SEQ ID NOs: 2, 70, 36, and 40, and(b) the beta chain comprises the amino acid sequence provided in any one of SEQ ID NOs: 12, 69, 38, 41 , 80, 81 and 82, or an amino acid sequence that has at least 90%, at least 95%, or at least 98% identity to the amino acid sequence provided in any one of SEQ ID NOs: 12, 69, 38, 41 , 80, 81 and 82.

14. The binding molecule of any preceding claim, wherein(a) the alpha chain comprises the amino acid sequence of SEQ ID NO: 70 and the beta chain comprises the amino acid sequence of SEQ ID NO: 69;(b) the alpha chain comprises the amino acid sequence of SEQ ID NO: 36 and the beta chain comprises the amino acid sequence of SEQ ID NO: 38;(c) the alpha chain comprises the amino acid sequence of SEQ ID NO: 40 and the beta chain comprises the amino acid sequence of SEQ ID NO: 41 ;(d) the alpha chain comprises the amino acid sequence of SEQ ID NO: 40 and the beta chain comprises the amino acid sequence of SEQ ID NO: 80;(e) the alpha chain comprises the amino acid sequence of SEQ ID NO: 40 and the beta chain comprises the amino acid sequence of SEQ ID NO: 81 ; or(f) the alpha chain comprises the amino acid sequence of SEQ ID NO: 40 and the beta chain comprises the amino acid sequence of SEQ ID NO: 82.

15. The binding molecule of any one of claims 1 to 11 , wherein the pMHC binding domain is in a single polypeptide chain format of the type Va-L-Vp, Vp-L-Va, Va-Ca-L-Vp, or Va-L-Vp-Cp, wherein Va and Vp are TOR a and p variable regions respectively, Ca and Cp are TOR a and p constant regions respectively, and L is a linker sequence.

16. The binding molecule of any preceding claim, further comprising an immune suppressor.

17. The binding molecule of claim 16, wherein the immune suppressor is an immune checkpoint agonist, optionally a PD-1 agonist.

18. The binding molecule of any preceding claim, wherein the immune suppressor comprises an antigen binding moiety that is capable of binding to an antigen.

19. The binding molecule of claim 18, wherein the antigen is PD-1 and the antigen binding moiety is a PD-1 agonist.

20. The binding molecule of claim 18 or claim 19, wherein the antigen binding moiety comprises an antibody or antigen binding fragment thereof.21 . The binding molecule of any one of claims 18 to 20, wherein the antigen binding moiety comprises a single domain antibody, optionally a VHH.

22. The binding molecule of claim 21 , wherein the single domain antibody binds to PD-1 and comprises CDRs, CDR1 , CDR2 and CDR3, having the following amino acid sequences:CDR1 - GFTFSSYA (SEQ ID NO: 43), optionally with one, two or three mutations therein, CDR2 - IASDGAST (SEQ ID NO: 44), optionally with one, two or three mutations therein, and CDR3 - CARGGYLTYDRY (SEQ ID NO: 45), optionally with one, two or three mutations therein.

23. The binding molecule of claim 21 or claim 22, wherein the single domain antibody is a VHH comprising the amino acid sequence of SEQ ID NO: 42, or a humanised version thereof, or an amino acid sequence having at least 80%, at least 90%, at least 95% or at least 98% identity to SEQ ID NO: 42.

24. The binding molecule of claim 21 or 22, wherein the single domain antibody is a VHH comprising the amino acid sequence of SEQ ID NO: 71 , or an amino acid sequence having at least 80%, at least 90%, at least 95% or at least 98% identity to SEQ ID NO: 71 .

25. The binding molecule of any one of claims 16 to 24, wherein the immune suppressor is covalently linked to the pMHC binding domain via the C- or N-terminus of the alpha or beta chain, optionally via a linker sequence, further optionally wherein the linker sequence is selected from SEQ ID NOs: 55 to 66 or 73.

26. The binding molecule of any one of claims 16 to 25, comprising(a) a first polypeptide chain comprising the immune suppressor and the beta chain of the pMHC binding domain; and(b) a second polypeptide chain comprising the alpha chain of the pMHC-binding domain.

27. The binding molecule of claim 26, wherein the C-terminus of the immune suppressor is covalently linked to the N-terminus of the TCR beta chain, optionally via the linker sequence of SEQ ID NO: 73.

28. The binding molecule of claim 26 or claim 27, wherein(a) the first polypeptide comprises an amino acid sequence provided in any one of SEQ ID NOs: 72, 46, 47, 83, 84 and 85, or an amino acid sequence that has at least 90%, at least 95%, or at least 98% identity to an amino acid sequence provided in any one of SEQ ID NOs: 72, 46, 47, 83, 84 and 85, and(b) the second polypeptide comprises an amino acid sequence provided in any one of SEQ ID NOs: 70, 36, and 40, or an amino acid sequence that has at least 90%, at least 95%, or at least 98% identity to an amino acid sequence provided in any one of SEQ ID NOs 70, 36, and 40.

29. The binding molecule of any one of claims 26 to 28, wherein(a) the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 72 and the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 70;(b) the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 46 and the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 36;(c) the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 47 and the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 40;(d) the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 83 and the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 40;(e) the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 84 and the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 40; or(f) the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 85 and the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 40.

30. The binding molecule of any preceding claim, further comprising a half-life extending domain, optionally comprising a first portion of an IgG Fc region (FC1) and a second portion of an IgG Fc region (FC2).31 . The binding molecule of any one of claims 16 to 29, further comprising a half-life extending domain comprising a first portion of an IgG Fc region (FC1) and a second portion of an IgG Fc region (FC2), wherein the binding molecule comprises(a) a first polypeptide chain comprising the immune suppressor and either (i) the alpha chain or (ii) beta chain of the pMHC binding domain;(b) a second polypeptide chain comprising FC1 and the other of (i) the alpha chain and (ii) the beta chain; and(c) a third polypeptide chain comprising FC2.

32. The binding molecule of claim 31 , wherein the C-terminus of the immune suppressor is covalently linked to the N-terminus of either (i) the alpha chain or (ii) beta chain of the pMHC binding domain, optionally via the linker sequence of SEQ ID NO: 73.

33. The binding molecule of claim 31 or claim 32, wherein the C-terminus of the other of (i) the alpha chain and (ii) the beta chain is covalently linked to the N-terminus of FC1 via an IgG hinge sequence, and / or wherein the third polypeptide comprises an IgG hinge sequence at the N- terminus of FC2, optionally wherein the IgG hinge comprises the amino acid sequence of SEQ ID NO: 50.

34. The binding molecule of any one of claims 31 to 33, wherein the first polypeptide chain comprises the beta chain of the pMHC binding domain and the second polypeptide chain comprises the alpha chain of the pMHC binding domain.

35. The binding molecule of any one of claims 30 to 34, wherein the half-life extending domain comprises(a) one or more amino acid substitutions which facilitate dimerisation of FC1 and FC2; and / or(b) one or more amino acid substitutions which prevent or reduce binding to FcyR; and / or(c) one or more amino acid substitutions which promote binding to FcRn.

36. The binding molecule of any one of claims 30 to 35, wherein(a) either FC1 or FC2 comprises the amino acid sequence provided in SEQ ID NO: 49 or 93, or an amino acid sequence that has at least 90%, at least 95%, or at least 98% identity to the amino acid sequence provided in SEQ ID NO: 49 or 93, and(b) the other of FC1 and FC2 comprises the amino acid sequence provided in SEQ ID NO: 52 or 94, or an amino acid sequence that has at least 90%, at least 95%, or at least 98% identity to the amino acid sequence provided in SEQ ID NO: 52 or 94.

37. The binding molecule of any one of claims 31 to 36, wherein(a) the first polypeptide comprises an amino acid sequence provided in any one of SEQ ID NOs: 72, 46, 47, 83, 84 and 85, or an amino acid sequence that has at least 90%, at least 95%, or at least 98% identity to an amino acid sequence provided in any one of SEQ ID NOs: 72, 46, 47, 83, 84 and 85;(b) the second polypeptide comprises an amino acid sequence provided in any one of SEQ ID NOs: 48, 53, 54, 97, 99 or 100, or an amino acid sequence that has at least 90%, at least 95%, or at least 98% identity to an amino acid sequence provided in any one of SEQ ID NOs: 48, 53, 54,97, 99 or 100; and(c) the third polypeptide chain comprises the amino acid sequence of SEQ ID NO: 51 or98, or an amino acid sequence that has at least 90%, at least 95%, or at least 98% identity to the amino acid sequence of SEQ ID NO: 51 or 98.

38. The binding molecule of any one of claims 31 to 37, wherein(a) the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 72, the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 48 and the third polypeptide chain comprises the amino acid sequence of SEQ ID NO: 51 ;(b) the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 46, the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 53 and the third polypeptide chain comprises the amino acid sequence of SEQ ID NO: 51 ;(c) the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 47, the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 54 and the third polypeptide chain comprises the amino acid sequence of SEQ ID NO: 51 ;(d) the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 83, the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 54 and the third polypeptide chain comprises the amino acid sequence of SEQ ID NO: 51 ;(e) the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 84, the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 54 and the third polypeptide chain comprises the amino acid sequence of SEQ ID NO: 51 ;(f) the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 85, the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 54 and the third polypeptide chain comprises the amino acid sequence of SEQ ID NO: 51 ;(g) a first polypeptide chain comprising the amino acid sequence of SEQ ID NO: 72, a second polypeptide chain comprising the amino acid sequence of SEQ ID NO: 97 and a third polypeptide chain comprising the amino acid sequence of SEQ ID NO: 98;(h) a first polypeptide chain comprising the amino acid sequence of SEQ ID NO: 46, a second polypeptide chain comprising the amino acid sequence of SEQ ID NO: 99 and a third polypeptide chain comprising the amino acid sequence of SEQ ID NO: 98;(i) a first polypeptide chain comprising the amino acid sequence of SEQ ID NO: 47, a second polypeptide chain comprising the amino acid sequence of SEQ ID NO: 100 and a third polypeptide chain comprising the amino acid sequence of SEQ ID NO: 98;(j) a first polypeptide chain comprising the amino acid sequence of SEQ ID NO: 83, a second polypeptide chain comprising the amino acid sequence of SEQ ID NO: 100 and a third polypeptide chain comprising the amino acid sequence of SEQ ID NO: 98;(k) a first polypeptide chain comprising the amino acid sequence of SEQ ID NO: 84, a second polypeptide chain comprising the amino acid sequence of SEQ ID NO: 100 and a third polypeptide chain comprising the amino acid sequence of SEQ ID NO: 98; or(l) a first polypeptide chain comprising the amino acid sequence of SEQ ID NO: 85, a second polypeptide chain comprising the amino acid sequence of SEQ ID NO: 100 and a third polypeptide chain comprising the amino acid sequence of SEQ ID NO: 98.

39. The binding molecule of any one of claims 31 to 37, wherein the first polypeptide chain comprises the amino acid sequence of SEQ ID NO: 83, the second polypeptide chain comprises the amino acid sequence of SEQ ID NO: 54 or 100 and the third polypeptide chain comprises the amino acid sequence of SEQ ID NO: 51 or 98.

40. The binding molecule of any preceding claim, wherein the pMHC-binding domain binds to the ALWGPDPAAA (SEQ ID NO: 1)-HLA-A*02 complex with an affinity which is at least at least 10- fold, at least 100-fold, at least 500-fold, or at least 1000-fold higher than its affinity for a ALLGPDPAAA (SEQ ID NO: 67)-HLA-A*02 complex.41 . A single domain antibody that binds to PD-1 comprising a CDR1 , CDR2 and CDR3, having the following amino acid sequences:CDR1 - GFTFSSYA (SEQ ID NO: 43), optionally with one, two or three mutations therein;CDR2 - IASDGAST (SEQ ID NO: 44), optionally with one, two or three mutations therein; and CDR3 - CARGGYLTYDRY (SEQ ID NO: 45), optionally with one, two or three mutations therein.

42. The single domain antibody of claim 41 , wherein(a) the single domain antibody is isolated; and / or(b) the single domain antibody is a VHH; and / or(c) the single domain antibody is a PD-1 -agonist; and / or(d) the single domain antibody binds to PD-1 with a KD in the range of about 1 nM to about 500 nM or in the range of about 50 nM to about 70 nM; and / or(e) the single domain antibody binds to an epitope in PD-1 comprising one or more or all of the following amino acids: E38, F59, P60, E61 , T75, Q76, L77, P78, N79 and G80, numbered according to SEQ ID NO: 101 ; and / or(f) the single domain antibody comprises the amino acid sequence provided in SEQ ID NO: 42 or a humanised version thereof, or an amino acid sequence having at least 80%, at least 90%, at least 95% or at least 98% identity to SEQ ID NO: 42; and / or(g) the single domain antibody comprises the amino acid sequence of SEQ ID NO: 71 , or an amino acid sequence having at least 80%, at least 90%, at least 95% or at least 98% identity to SEQ ID NO: 71.

43. A binding molecule comprising(a) the single domain antibody of claim 41 or claim 42;(b) a pMHC-binding domain, optionally comprising (i) an alpha chain, comprising at least a TOR alpha chain variable domain, and (ii) a beta chain, comprising at least a TOR beta chain variable domain; and(c) optionally, a half-life extending domain.

44. A nucleic acid encoding(a) the binding molecule of any one of claims 1 to 30 or 40, wherein the alpha and beta chains are encoded within a single open reading frame, or within two distinct open reading frames;(b) the binding molecule of any one of claims 31 to 39, wherein the first, second and third polypeptide chains are encoded within a single open reading frame, or within distinct open reading frames; and / or(c) the single domain antibody of claim 41 or claim 42 or the binding molecule of claim 43.

45. An expression vector comprising the nucleic acid of claim 44.

46. A cell harbouring(a) the expression vector of claim 45;(b) a first expression vector comprising a nucleic acid encoding a first polypeptide comprising the beta chain of the binding molecule of any one of claims 1 to 30 or 40 and a second expression vector comprising a nucleic acid encoding a second polypeptide comprising the alpha chain of the binding molecule of any one of claims 1 to 30 or 40; or(c) a first expression vector comprising a nucleic acid encoding the first polypeptide of the binding molecule of any one of claims 31 to 39, a second expression vector comprising a nucleic acid encoding the second polypeptide of the binding molecule of any one of claims 31 to 39, and a third expression vector comprising a nucleic acid encoding the third polypeptide of the binding molecule of any one of claims 31 to 39.

47. A non-naturally occurring and / or purified and / or engineered cell, preferably a T-cell, presenting the binding molecule of any one of claims 1 to 14.

48. A pharmaceutical composition comprising the binding molecule of any one of claims 1 to 40 or 43, the single domain antibody of claim 41 or 42, the nucleic acid of claim 44, the expression vector of claim 45, and / or the cell of claim 46 or 47, together with one or more pharmaceutically acceptable carriers or excipients.

49. The binding molecule of any one of claims 1 to 40 or 43, the single domain antibody of claim 41 or claim 42, the nucleic acid of claim 44, the expression vector of claim 45, and / or the cell of claim 46 or 47, for use in medicine, preferably in a human subject.

50. The binding molecule of any one of claims 1 to 40 or 43, the single domain antibody of claim 41 or claim 42, the nucleic acid of claim 44, the expression vector of claim 45, and / or the cell of claim 46 or 47, for use in a method of treating diabetes, preferably in a human subject.51 . A method of producing the binding molecule of any one of claims 1 to 40 or 43, or the single domain antibody of claim 41 or claim 42, the method comprising a) maintaining a cell according to claim 46 or 47 under optimal conditions for expression of the binding molecule or single domain antibody and b) isolating the binding molecule or single domain antibody.