Peptides that block presentation of antigenic islet peptides by HLA-DQ8 and methods for treating type-1 diabetes
The disclosure provides polypeptides that specifically bind to HLA-DQ8 for treating Type 1 Diabetes (TID) and methods using same for reducing autoimmune destruction of pancreatic islet beta cells. In particular, the present disclosure relates to peptides containing at least one D-amino acid that are capable of blocking the presentation of antigenic islet peptides (e.g., lnsB:9-23) by HLA-DQ8, and to their uses, especially as it relates to the prevention and/or treatment of TID.
1 . A polypeptide comprising,
(i) the amino acid sequence of SEQ ID NO: 1, wherein:
X 1 is V, L, F, or Y;
X 2 is L, A, S, C, or G; or
(ii) the amino acid sequence of SEQ ID NO: 2, wherein:
X 1 is V, L, F, or Y;
X 2 is L, A, S, C, or G;
X 3 is L or G;
X 4 is H or G; and
wherein each amino acid of the amino acid sequence is a D-amino acid.
2 . The polypeptide claim 1 , further comprising:
(i) one or more additional D-amino acid residues at the NH 2 terminus of the amino acid sequence, or
(ii) two additional D-amino acid residues at the NH 2 terminus of the amino acid sequence, or
(iii) two additional D-amino acid residues selected from the group consisting of: FF, HS, SH, RS, and KS at the NH 2 terminus of the amino acid sequence.
3 . The polypeptide of claim 1 , further comprising:
(i) one or more additional D-amino acid residues at the COOH terminus of the amino acid sequence, or
(ii) two additional D-amino acid residues at the COOH terminus of the amino acid sequence, or
(iii) two additional D-amino acid residues selected from the group consisting of: SG, DF, FD, ES, and SF at the COOH terminus of the amino acid sequence.
4 . The polypeptide of claim 1 comprising, the amino acid sequence of any of SEQ ID NOs: 3-16.
5 . The polypeptide of claim 1 , wherein the polypeptide specifically binds to an HLA-DQ8.
6 . The polypeptide of claim 5 , wherein the HLA-DQ8 is comprised on a cell.
7 . A complex comprising:
(i) the polypeptide of claim 1 ; and
(ii) an HLA-DQ8, optionally wherein the HLA-DQ8 is a human HLA-DQ8.
8 . The complex of claim 7 , wherein the HLA-DQ8 comprises:
(i) an alpha chain that is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 99.5% identical to the amino acid sequence of SEQ ID NO: 17 or an alpha chain comprising the amino acid sequence of SEQ ID NO: 17; and/or,
(ii) a beta chain that is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 99.5% identical to the amino acid sequence of SEQ ID NO: 18 or a beta chain comprising the amino acid sequence SEQ ID NO: 18.
9 . The complex of claim 7 , wherein the complex is on an antigen presenting cell (APC), optionally, wherein the APC is a professional APC, a macrophage, dendritic cell, B-cell, or T-cell.
10 . The complex of claim 9 , wherein the APC:
(i) expresses an MHC class II molecule; and/or,
(ii) is human; and/or,
(iii) has a decreased ability to induce T-cell activation as compared to a second APC comprising HLA-DQ8 that is bound to InsB: 9-23, optionally,
wherein the APC has a 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 95%, 98%, or 99% decreased ability to induce T-cell activation.
11 . The complex of claim 10 (iii), wherein the APC has a decreased ability to induce T-cell activation in vivo or in vitro.
12 . The complex of claim 7 , wherein the complex is in a subject, optionally, wherein the subject is a human.
13 . A method, comprising:
(i) inhibiting activation of a cytotoxic T-cell, comprising contacting an APC with the polypeptide of claim 1 , wherein the APC comprises HLA-DQ8, optionally wherein the method is performed in vitro, or in vivo; or
(ii) treating a subject having or suspected of having TID comprising, comprising administering to the subject the polypeptide of claim 1 , optionally complexed with HLA-DQ8, optionally comprising a pharmaceutically acceptable carrier, optionally, wherein the subject is human, optionally wherein the polypeptide or the complex is administered to the subject parenterally or non-parenterally; or
(iii) making an HLA-DQ8 inhibiting peptide, comprising:
(a) identifying a peptide that binds to HLA-DQ8 in a subject; and
(b) synthesizing a retro-inverso peptide of the peptide identified in step (a), optionally, wherein the identifying comprises:
(i) isolating APCs that express HLA-DQ8 from a subject; and
(ii) obtaining the amino acid sequence of a peptide bound to the HLA-DQ8 of step (i).
14 . A polypeptide comprising,
an amino acid sequence of SEQ ID NO: 4 or an amino acid sequence of SEQ ID NO: 12, wherein each amino acid of the amino acid sequence is a D-amino acid.
15 . The polypeptide of claim 14 , wherein the polypeptide specifically binds to an HLA-DQ8.
16 . A complex comprising:
(i) the polypeptide of claim 14 ; and
(ii) an HLA-DQ8, optionally wherein the HLA-DQ8 is a human HLA-DQ8.
17 . The complex of claim 16 , wherein the complex is on an antigen presenting cell (APC), optionally, wherein the APC is a professional APC, a macrophage, dendritic cell, B-cell, or T-cell.
18 . The complex of claim 17 , wherein the APC:
(i) expresses an MHC class II molecule; and/or,
(ii) is human; and/or,
(iii) has a decreased ability to induce T-cell activation as compared to a second APC comprising HLA-DQ8 that is bound to InsB: 9-23, optionally,
wherein the APC has a 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 95%, 98%, or 99% decreased ability to induce T-cell activation.
19 . The complex of claim 15 (iii), wherein the APC has a decreased ability to induce T-cell activation in vivo or in vitro.
20 . The complex of claim 16 , wherein the complex is in a subject, optionally, wherein the subject is a human.