Peptides and methods for the treatment of diabetes
The invention relates to peptides such as HCPYCSLQPLALEGSLQKRG [SEQ ID NO: 26] and their use in the treatment of type 1 diabetes and the generation of cytolytic CD4+ T cell.
1. An in vitro method for the generation of a population of cytolytic CD4+ T cells against antigen presenting cells (APC) presenting insulin epitopes, comprising the steps of:
providing peripheral blood cells;
contacting said cells in vitro with an isolated immunogenic peptide comprising the amino acid sequence of HCXX[CST]SLQPLALEGSLQK [SEQ ID NO:7] or H[CST]XXCSLQPLALEGSLQK [SEQ ID NO:8] wherein X stands for any amino acid, and wherein the peptide has a length of between 12 and 50 amino acids; and
expanding said cells in the presence of IL-2.
2. The in vitro method of claim 1 , wherein the amino acid sequence comprises HCXXCSLQPLALEGSLQK [SEQ ID NO: 9] wherein X stands for any amino acid.
3. The in vitro method of claim 1 , wherein the amino acid sequence consists of HCPYCSLQPLALEGSLQKRG [SEQ ID NO: 26].
4. The in vitro method of claim 1 , wherein the amino acid sequence consists of HCXX[CST]SLQPLALEGSLQK [SEQ ID NO:7] or H[CST]XXCSLQPLALEGSLQK [SEQ ID NO:8] wherein X stands for any amino acid.
5. The in vitro method of claim 1 , wherein the amino acid sequence consists of HCXXCSLQPLALEGSLQK [SEQ ID NO: 9] wherein X stands for any amino acid.
6. A population of cytolytic CD4+ T cells against APC presenting insulin epitopes obtained by the method of claim 5 .
7. The population of cytolytic CD4+ T cells of claim 6 , wherein the cells are characterised by an expression level of FasL and/or Interferon gamma that is increased when compared to cytolytic CD4+ T cells obtained by contacting peripheral blood cells in vitro with an isolated immunogenic peptide comprising the amino acid sequence of HCPYCVRSLQPLALEGSLQKRG [SEQ ID NO: 25] and expanding said cells in the presence of IL-2.
8. The population of cytolytic CD4+ T cells of claim 7 , wherein the cells are characterised by an expression level of Granzyme B that is increased when compared to cytolytic CD4+ T cells obtained by contacting peripheral blood cells in vitro with an isolated immunogenic peptide comprising the amino acid sequence of HCPYCVRSLQPLALEGSLQKRG [SEQ ID NO: 25] and expanding said cells in the presence of IL-2.
9. A pharmaceutical composition comprising the cytolytic CD4+ T cells of claim 6 .
10. A method of treating type 1 diabetes in a mammal, comprising administering to a subject in need thereof a therapeutically sufficient amount of the cytolytic CD4+ T cells of claim 6 .
11. The method according to claim 10 , wherein the subject is a human subject.