DIETARY PROTECTION AGAINST DIABETES IN NOD MICE - LACK OF A MAJOR CHANGE IN THE IMMUNE-SYSTEM

Pregestimil, a hypoallergenic infant formula in which casein hydrolysa te replaces protein, protects NOD mice against diabetes, a T-cell-medi ated autoimmune disease. Female and cyclosphophamide (Cy)-treated male NOD mice were used to assess whether a modification of cellular immun e mechanisms occurred when animals were fed Pregestimil from weaning t o 110 days of life. Insulitis, sialitis and thyroiditis were observed, and the splenic T-cell proliferative response was measured; The abili ty of splenic T-cells of NOD mice in the Pregestimil group to transfer diabetes adoptively to young irradiated male NOD mice was also assess ed. Pregestimil protected female NOD mice against spontaneous diabetes and male NOD mice against acute Cy-induced diabetes. Addition of bovi ne serum albumin (10 %) to the diet did not alter the preventive effec t The Pregestimil diet also lessened insulitis severity in Cy-treated males, though not in females. Sialitis and thyroiditis, observed mainl y in females, were not modified by the diets. The TOP-mediated prolife rative response of splenocytes tended to increase specifically in Preg estimil-fed and Cy-treated males. Sensitivity to IL-2 was improved. In females, the TOP-mediated proliferative response and the ability of T cells to transfer diabetes adoptively were unchanged. It is concluded that the protective effect of Pregestimil against diabetes in NOD mic e cannot be explained by major changes in peripheral immune response.