Abstract
Insulin-dependent diabetes mellitus (IDDM) results from a T cell-dependent autoimmune destruction of insulin-producing pancreatic β cells. In the present study, expression of adhesion molecule ICAM-1 (CD54) on pancreatic β cells was studied in normal, obese hyperglycemic (ob/ob), and nonobese diabetic (NOD) mice. Freshly isolated pancreatic β cells from ob/ob mice did not express ICAM-1, but treatment of the cells with IL-1-β, TNF-α, or INF-γ strongly induced its expression as measured by immunofluorescence flow cytometry. The cytokines acted in a dose- and time-dependent manner. Maximal induction by either cytokine occurred at 24 hr and thereafter expression decreased, except for INF-γ. Immunoprecipitation from IL-1-β-treated β cells demonstrated a cell-surface glycoprotein with an apparent molecular weight of 95 kDa. ICAM-1 expression was undetectable on pancreatic β cells of normal and ob/ob mice as measured by immunohistochemistry. In NOD mice at different ages (1 to 6 months) ICAM-1 was also undetectable on β cells, in contrast to the strong expression on infiltrating mononuclear cells. The present study indicates that mouse pancreatic β cells, under certain conditions, can express ICAM-1.
