Interferon-γ Induces the Expression of HLA-A,B,C but Not HLA-DR on Human Pancreatic β-Cells*

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Abstract
We examined the effect of interferon-γ (IFNγ) on expression of the major histocompatibility proteins on cultured human islet cells isolated from adult and fetal pancreas and from an insulinoma. While the pancreatic β-cells from different sources varied in their responses to IFNγ, in all instances the expression ofHLA-A,B,C protein was increased. Pancreatic β-cells did not express HLA-DRx protein, before or after culture of the islets in IFNγ, although HLA-DR protein expression was induced on some non-β-cells. These findings areat variance with those reported with thyroid follicular cells, in which IFNγ induced expression of HLA-DR. We, therefore, conclude that the interaction between the immune and the endocrine systems may be endocrine cell specific. The up-regulation of HLA-A,B,C protein on β-cells by IFNγ provides a mechanism for enhanced targetting to the β-cells of autoreactive cytotoxic T–lymphocytes and, hence, for amplifying β-cell destruction.