Induction of HLA-DR antigen expression in human endometrial epithelial cells in vitro by recombinant gamma-interferon

Recent studies suggest that HLA-DR antigens may be inducible in some normal epithelial cells. Therefore, we studied the expression of these molecules in epithelial cell cultures derived from 9 proliferative and 7 secretory endometria with and without treatment by recombinant gamma-interferon (gamma-IFN). A panel of monoclonal antibodies to HLA-DR antigens, T cells, B cells, macrophages, endothelial cells, and cytokeratin was used to stain the cultured cells by the avidin-biotin complex method. The cultures consisted only of epithelial cells as demonstrated by expression of cytokeratin and by electron microscopy and did not contain any T or B cells, macrophages, or endothelial cells. The endometrial epithelial cells were HLA-DR-negative under routine culture conditions but expressed HLA-DR antigens after gamma-IFN treatment in a dose- and time-dependent fashion. The findings indicate that endometrial epithelium can actively synthesize HLA-DR antigens in vitro after induction by gamma-IFN.