Induction of a polarized micro-environment by human T cells and interferon-gamma in three-dimensional spheroid cultures of human endometrial epithelial cells.

Expression of human leukocyte antigen (HLA)-DR molecules and proliferation of epithelium in human endometrium are polarized. We have suggested that the induction of such a polarized micro-environment is T cell and interferon (IFN)-gamma dependent. The present study was designed to demonstrate the induction of such a micro-environment around T cells and around the source of IFN-gamma. Spheroids reminiscent of endometrial glands were formed by allowing three-dimensional aggregation of endometrial epithelial cells of a cloned HLA-DR negative endometrial carcinoma cell line (ECC1) over agarose. Both HLA-DR expression and inhibition of proliferation were found to be directly dependent on the dose of IFN-gamma that was allowed to diffuse in the agarose beneath the spheroids. To show that the interaction of the epithelial cells with activated T cells also induces HLA-DR molecules in a paracrine fashion in the epithelial cells, ECC1 spheroids were co-cultured with increasing numbers of allogeneic peripheral blood T cells for various time-intervals. T cells bound to the ECC1 cells, and became activated as indicated by the expression of interleukin (IL)-2 receptor and HLA-DR molecules. A focal HLA-DR expression became apparent in the ECC1 cells adjacent to the T cells. As the number of T cells added to spheroid cultures was increased, a concomitant increase in the number of HLA-DR positive ECC1 cells occurred and HLA-DR immunoreactivity was enhanced in each cell. There was a corresponding decrease in the proliferation of the ECC1 cells in T cell-ECC1 spheroid co-cultures. Based on these data, we suggest that activation of T cells is associated with the induction of HLA-DR expression and inhibition of proliferation in a paracrine fashion in the epithelial cells and may be responsible for the creation of a polarized micro-environment in vivo.