Target Auto-antigens and Pancreatic beta cell destructive T lymphocytes in Type 1 Diabetes

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This study focused on the T lymphocytes against the pancreatic beta cell antigens in Type 1 diabetes patients. So far, we have reported the cytotoxic T CD8^+lymphocytes against the insulin peptide in the early -diagnosed Type 1 diabetes patients.In this study, the firstly, we tried the flowcytometry assay for detection of the cytotoxic T CD8^+ lymphocytes using the MHC-peptide tetramer. However, the positive cells were not significantly detected. We suspected that the low frequency of that cell might be reason why we could not detected.The secondly, we establish the enzyme-linked immunospot (ELISPOT) assay using the insulin overlapping peptides. We have made the seven kinds from A-chain and the sixteen kinds from B-chain of the insulin peptides in 15 amino acids length for CD4^+ T lymphocytes. Furthermore, we have also made the 11 kinds from A-chain and the 20 kinds of B-chain of the insulin peptides in 8-11 amino acids length for CD8^+ lymphocytes,In results, 13 patients among 19 early-diagnosed patients have showed positive in gamma-INF ELISPOT assay, but no one among 17 healthy controls. In IL-4 ELISPOT assay, no positive cell has been detected at all. Among the overlapping peptides, the positive response was detected against the peptides near portion of the peptides that have been already reported.In conclusion, ELISPOT assay have revealed that the insulin peptide specific T lymphocytes, that secrete gamma-INF, existed in the peripheral blood of the early-diagnosed human Type 1 diabetes patients. These T lymphocytes might play an important role in the destruction of the beta cells.