PTPRN and diabetes mellitus: Moreover, the disease induced was clearly mediated by the proinsulin-2 derived peptides and did not result merely from a priming effect of the adjuvant and/or pertussis toxin, as mice treated with the 377-amino acid c-terminal region of human Islet cell Antigen-2 (IA-2) in CFA s.c. and Pertussis toxin i.p. remained diabetes-free throughout the 20-week experiment (Fig. 1c).