Chorionic gonadotropin regulation of leukocytic phagocytic activity in the formation of a primary humoral immune response

Abstract

Experiments on male Swiss mice studied the effect of chorionic gonadotropin (CG) on the phagocytic activity of peripheral blood leukocytes and peritoneal macrophages, by taking into account the stages of formation of a humoral immune response. The administration of CG was found to stimulate the splenic production of antibody-forming cells (AFC) and to elevate the serum level of endogenous progesterone (Pr) in the mice. Irrespective of the dose, CG suppressed the phagocytic activity of peripheral blood neutrophils and peritoneal macrophages in the in vitro system. Evaluation of the effect of CG on the phagocytic activity of leukocytes and macrophages revealed no statistically significant changes in nonimmunized animals. Whatever the dose was, CG, however, enhanced the phagocytic activity of neutrophils and macrophages at the peak of formation of a humoral immune response. A correlation was established between the phagocytic activity of leukocytes and the elevated level of Pr. The findings indicate that despite the intrinsic phygocyte-depressive effect of CG, its induced Pr synthesis can activate phagocytes only during immunization. Hormone-dependent activation of phagocytes of peripheral blood and peritoneal cavity can be one of the mechanisms responsible for fetal protection from possible pathogens, by determining the high level of the natural immunity system as a whole.