The oestrogen antagonists, tamoxifen and FC-1157a, display oestrogen like effects on human lymphocyte functions in vitro.

We studied the in vitro effects of two anti-oestrogens (tamoxifen and FC-1157a) on human lymphocyte functions in pokeweed mitogen (PWM) stimulated cultures. Addition of 1-100 nmol/l of tamoxifen or FC-1157a to PWM cultures significantly increased the number of immunoglobulin secreting cells. This concentration of tamoxifen did not affect the proliferative response. Further experiments with fractionated lymphocyte subpopulations showed that the anti-oestrogens displayed their enhancing effect by inhibiting the suppressive function of T8+ cells. The anti-oestrogens had no significant effect on the T-independent activation of B cells with Epstein-Barr virus. We conclude that the anti-oestrogens display an effect on the functions of human lymphocytes similar to that previously reported for oestradiol (Paavonen, Andersson & Adlercreutz, 1981).