BOVINE LUTEAL CELLS ELICIT MAJOR HISTOCOMPATIBILITY COMPLEX CLASS II-DEPENDENT T-CELL PROLIFERATION

Major histocompatibility complex (MHC) class II molecules are expresse d in the bovine corpus luteum (CL) in a manner correlating with luteol ysis. Whether bovine luteal cells can stimulate T-cell proliferation i n a class II-restricted manner was investigated. Staphylococcal entero toxin B (SEB) enhances T-cell proliferation by a mechanism requiring M HC class II molecules and was used to examine stimulation of T-cell pr oliferation by luteal cells. Luteal cells from midcycle or regressing CL (induced by prostaglandin F-2 alpha) were cocultured with autologou s T cells in the presence of no treatment, SEB (1 mu g/ml), or SEB + a nti-MHC class II antibody (3 mu g/ml); and proliferation was assessed by incorporation of tritiated thymidine. T cells proliferated in the p resence of cells from regressing CL more than when in the presence of midcycle cells (118 309 +/- 20 567 vs. 75 261 +/- 12 494 cpm; p < 0.05 ). Anti-MHC attenuated this response of cells from regressing CL (81 1 08 cpm +/- 13 249; p < 0.05). Without SEB, T cells proliferated when c ultured with cells from regressing, but not midcycle, CL (4637 +/- 816 vs. 2117 +/- 589 cpm; p < 0.03). These results suggest that luteal ce lls can function as antigen-presenting cells in vitro and that prostag landin F-2 alpha may enhance their ability to present antigen.