islet amyloid polypeptide is not a target antigen for cd8+ t-cells in type 2 diabetes

background: type 2 diabetes (t2d) is a chronic metabolic disorder in which beta-cells are destroyed. the islet amyloid polypeptide (iapp) produced by beta-cells has been reported to influence beta-cell destruction. objective: to evaluate if iapp can act as an autoantigen and therefore, to see if cd8 + t-cells specific for this protein might be present in t2d patients. methods: peripheral blood mononuclear cells (pbmc) were obtained from human leukocyte antigen (hla)-a2 + t2d patients and non-diabetic healthy subjects. cells were then screened for peptide recognition using elispot assay for the presence of ifn-γ producing cd8 + t-cells against two hla class i-restricted epitopes derived from iapp (iapp 5-13 and iapp9-17) and common viral antigenic minimal epitopes flu mp 58-66, cmv495–503, ebv280–288 and hiv77–85 as controls. results: a total of 36.4% of patients and 56.2% of healthy subjects showed a response against iapp 5-13 peptide. no significant difference in response against this peptide was noted between the patients and the healthy donors. with respect to peptide iapp 9-17, although healthy subjects showed a higher mean number of spot forming cells than the patients, the difference was not significant; 36.4% of patients and 37.5% of controls responded to this peptide. the response of healthy subjects to the common viral peptides was stronger than that of the patients, though the result was not significant. conclusions: it is unlikely that iapp would be a target for cd8+ t-cells in diabetic patients; however, the trend observed toward a lower response of t2d patients against iapp and common viral peptides may imply a decreased immune response in these patients.