Chromogranin A Deficiency Confers Protection from Autoimmune Diabetes Via Multiple Mechanisms

Enteroviruses, including the Coxsackievirus Bs (CVB), have been implicated as causal agents in human type 1 diabetes. Immunization of at-risk individuals with a CVB vaccine provides an attractive strategy for elucidating the role of CVBs in the disease etiology. Previously we have shown that an inactivated whole-virus vaccine covering all CVB serotypes (CVB1-6) is safe to administer and highly immunogenic in preclinical models, including non-human primates. Before initiating clinical trials with this type of vaccine it was also important to address whether a) the vaccine itself induces adverse immune reactions including accelerating diabetes onset in a diabetes prone host and b) the vaccine can prevent CVB induced diabetes in a well-established disease model. Here we present results from studies in which female NOD mice were left untreated, mock-vaccinated or vaccinated with CVB1-6 vaccine and monitored for insulitis occurrence or diabetes development. We demonstrate that vaccination induces virus neutralizing antibodies without altering insulitis scores or the onset of diabetes. We also show that NOD mice vaccinated with a CVB1 vaccine are protected from CVB-induced accelerated disease onset. Taken together, these studies show that CVB vaccines do not alter islet inflammation or accelerate disease progression in an animal model that spontaneously develops autoimmune type 1 diabetes. However, they can prevent CVB-mediated disease progression in the same model.