Hla DR, DP, DQ Induction in Human Islet β Cells by the Cytokine Combination IFN-γ + TNF-α

Abstract

Human islet β cells do not express HLA Class II normally, yet, in the diabetic pancreas, β cells are selectively positive for Class II and this may facilitate their recognition by T cells. It has been demonstrated that human β cells can be induced to express Class II when cultured with IFN-γ + TNF-α or IFN-γ + TNF-β. To assess whether or not they can be induced to express the products of the Class II subregions, DR, DP and DQ, human islet cultures from 10 pancreases were supplemented with the combination of IFN-γ + TNF-α using MoAbs specific for DR, DP and DQ products, and antibodies to insulin and glucagon. The combination IFN-γ + TNF-α (100–1000 U/ml each) was able to induce the expression of the three subregions in both β and α cells. The induction of subregion expression followed the hierarchy DR > DQ ⩾ DP. The capability of β cells to express all three Class II subregions supports the possibility that these cells can present their self antigens to T cells.

Key Words:

• Type I diabetes
• β cells
• HLA-Classs II subregion.