Chorionic gonadotropin-induced cell proliferation and polyclonal immunoglobulin synthesis in human mononuclear cells

Some fetal and placental proteins may play a role in stimulating normal and malignant cell proliferation. We studied the effect of human chorionic gonadotropin (hCG) on the proliferative response of mitogen or alloantigen-activated, human peripheral blood mononuclear cells (PBM). The effect of hCG on polyclonal immunoglobulin synthesis was determined in pokeweed mitogen-activated cultures of PBM. hCG had a statistically discernible, augmenting effect on thymidine uptake in lectin-stimulated mononuclear cell cultures. This effect appeared to be dose-dependent, with an optimal range at 50-150 ng/hCG/ml. Polyclonal IgG and IgM synthesis was also significantly increased, both in PWM-stimulated and PWM-free cultures of PBM. Parallel studies with a rapidly growing EB-virus transformed lymphoblastoid line showed no hCG effect. In contrast to previous reports on the immunosuppressive action of hCG, we conclude that hCG functions, in our experimental conditions, as a mitogen and a stimulator of polyclonal immunoglobulin synthesis.