Evidence of T-cell activation and potential cytokine action in human endometrium.

Antigenic epitopes have been described whose expression characterizes early or late stages of activation of T-cells. In this study the expression of early activation antigen, interleukin-2 receptor was compared with the expression of late activation antigens, HLA-DR, HLA-DP, and HLA-DQ molecules of the major histocompatibility complex II, and very late activation antigen, VLA-1 of the integrin superfamily of molecules in 43 human endometria. These molecules were localized by their reactivity with monoclonal antibodies in an avidinbiotin-complex procedure. Interleukin-2 receptor was not expressed in human endometria; however, endometrial T-cells within lymphoid aggregates, some scattered in endometrial stroma and a few within epithelium, expressed HLA-DR, HLA-DP, HLA-DQ, and VLA-1. In addition, expression of the receptor of interferon-gamma, a product of activated T-cells, was observed on endometrial epithelium. Evidence for activation of T-cells and expression of interferon-gamma receptor in human endometrial epithelium suggests that endometrium may be an active site for cytokine action.