The Hsp60 peptide p277 enhances anti-CD3 mediated diabetes remission in non-obese diabetic mice

•Enhanced remission after anti-CD3 and Hsp60 peptide p277 combination treatment.•Protection occurs only in part through TLR2 signaling.•The effect is characterized by increased Treg numbers and decreased insulitis.

Type 1 diabetes (T1D) is characterized by the immune-mediated destruction of pancreatic beta cells leading to inadequate glycemic control. Trials with immunomodulatory monotherapies have shown that the disease course can in principle be altered. The observed preservation of endogenous insulin secretion however is typically transient and chronic treatment is often associated with significant side effects.Here we combined anti-CD3 with the Hsp60 peptide p277, two drugs that have been evaluated in Phase 3 trials, to test for enhanced efficacy. Female NOD mice with recent onset diabetes were given 5 μg anti-CD3 i.v., on three consecutive days in combination with 100 μg of p277 peptide in IFA s.c., once weekly for four weeks. Anti-CD3 alone restored normoglycemia in 44% of the mice while combination therapy with anti-CD3 and p277 induced stable remission in 83% of mice. The observed increase in protection occurred only in part through TLR2 signaling and was characterized by increased Treg numbers and decreased insulitis. These results have important implications for the design of combination therapies for the treatment of T1D.