CD80 and diabetes mellitus: Comparable to the mutant ppinsΔA12-21 antigen, proteasome-mediated degradation of pins resulted in a high turnover of this antigen in transiently transfected cells.6, 8 Injection of pCI/pins into RIP-B7.1 tg mice inefficiently induced late-onset autoimmune diabetes,6 but we could not unequivocally assign CD8+ T cell specificities to diabetes development.