Immunohistochemical localization of interferon-γ in normal human ovary

AbstractThere is increasing evidence that cytokines are important intraovarian non-steroidal regulators. The aim of the present study was to evaluate the presence in the human ovary of interferon (IFN)-γ, a cytokine produced by T lymphocytes after mitogenic or antigenic stimulation. Very low levels of IFN-γ (0.025–0.057 IU/ml) were found in follicular fluid of large spontaneously maturing follicles, in the ovarian vein (< 0.01–0.019 IU/ml) or peripheral blood (< 0.01–0.06 IU/ml). The avidin-biotin immunocytochemical technique, with appropriate monoclonal antibodies, was used to localize IFN-γ-positive cells, human leukocyte antigen (HLA)-DR molecules, activated T cells, T helper/inducer cells and T cyto-toxic/suppressor cells. IFN-γ-positive cells were only detected in preovulatory follicles, associated with the follicular basal lamina, thecal vessels and interstitial tissue. In the same large follicles very few T helper/inducer cells were detected, but a high proportion of Tlymphocytes expressed the CD8 phenotype in the theca, interstitial tissue and follicular cavity. No IFN-γ-positive cells were observed in preantral and small antral follicles. The results indicate that the human ovary contains immunoreactive IFN-γ, suggesting that the cytokine plays a paracrine role in human ovarian function.Key Words: CD8-POSITIVE T LymphocytesCytokinesInterferon-γOvarian PhysiologyReproductive Neuroimmunology