THE PATHOGENESIS OF ADOPTIVE MURINE AUTOIMMUNE DIABETES REQUIRES AN INTERACTION BETWEEN ALPHA-4-INTEGRINS AND VASCULAR CELL-ADHESION MOLECULE-1

An adoptive transfer model of insulin-dependent diabetes mellitus (IDDM) in the nonobese diabetic mouse was used to examine the roles of alpha 4-integrin, vascular cell adhesion molecule 1 (VCAM-1); and intercellular adhesion molecule 1 (ICAM-1) in the pathogenesis of autoimmune diabetes. Antibodies specific for both alpha 4-integrin and one of its ligands, VCAM-1, were able to delay onset of diabetes and decrease the incidence of the disease in adoptive transfer studies. This blocking of disease was accompanied by a marked decrease in lymphocytic infiltration of the islets of Langerhans. Furthermore, these antibodies preferentially block entrance of CD4 T cells into the tissue. Antibodies specific for ICAM-1 had little effect on the onset or incidence of IDDM. Thus, we conclude that an alpha 4-integrin-VCAM-1 interaction is important in T cell entry into the islets of Langerhans and in the pathogenesis of IDDM. In addition, the cascade of events leading to T cell transit across endothelium may be different for CD4 and CD8 cells, and may differ depending on the endothelium involved. Our results support the more general conclusion that an alpha 4-integrin-VCAM-1 interaction may be crucial in allowing activated effector CD4 T cells to leave the blood and enter tissue to clear infection.