HUMAN LUTEAL CELLS EXPRESS LEUKOCYTE FUNCTIONAL ANTIGEN (LFA)-3

Leukocyte functional antigen-3 (LFA-3)/cluster of differentiation-58 (CD-58) antigen is known as a ligand for CD-2 antigen, which is a specific surface marker of T-lymphocytes. To investigate the involvement of T-lymphocytes on corpus luteum (CL) function, the expression of LFA-S in human CL was examined by the indirect immunofluorescence method with frozen sections. LFA-3 was not detected on the granulosa cells of primordial, primary, or atretic follicles, but was weakly expressed on the granulosa cells of growing and preovulatory follicles. After ovulation, LFA-3 was clearly expressed on large luteal cells of the CL in any stage of the luteal phase, and the highest expression was observed in the midluteal phase. Antigen expression was also observed in the large luteal cells in CL of pregnancy. Human granulosa cells were isolated hom the patients who had undergone in vitro fertilization treatment and were cultured in vitro with or without hCG (1 IU/mL), tumor necrosis factor-alpha (TNF alpha; 10 ng/mL), or interleukin-1 alpha (10 ng/mL). By the indirect immunofluo-rescence method, LFA-S was detected on granulosa cells after culture for 1 day, although the fluorescence intensity was very weak. LFA-3 was clearly detected on granulosa cells after 7 days of culture, especially on those with TNF alpha. Flow cytometrical analysis with 7-day cultured cells showed that the percent positivity of LFA-3-positive granulosa cells cultured with TNF alpha was significantly higher than that of the controls (without treatment; 66.5 +/- 3.7% vs. 34.3 +/- 4.9%; P < 0.01; n = 7). The percent positivity of cells cultured with interleukin-la was slightly higher (51.5 +/- 4.5%; P < 0.1) than that of the controls, whereas treatment with hCG caused no significant difference (46.6 +/- 4.7%) from the controls. These findings indicate that LFA-3 is a differentiation antigen of human granulosa cells. They also suggest that large luteal cells can interact, through LFA-3 molecules, with the CD-2 antigen-positive T-lymphocytes invading the CL after ovulation, and that the expression of LFA-3 is under the control of some cytokines, including TNF alpha.