DIFFERENTIAL EFFECT OF PREGNANCY OR GESTAGENS ON HUMORAL AND CELL-MEDIATED-IMMUNITY

Abstract

The reactivity of spleen lymphocytes in a mixed lymphocyte culture and the in vivo PFC [plaque-forming cell] response to sheep erythrocytes were evaluated in pregnant female mice. The data was compared with those observed in virgin sexually mature female mice treated daily with progesterone or human chorionic gonadotropin (HCG) or human prolactin. The mixed lymphocyte reactivity is depressed at mid-pregnancy, whereas the PFC response is increased. Comparable immunological modifications were found in mice treated with HCG, but not in animals treated with progesterone or prolactin. The similarity between HCG treatment and pregnancy suggests that the rate of gonadotropin release may be one of the earliest events responsible for the immunological disturbances present during pregnancy, although its action on the lymphoid system seems to require the presence of the ovary. From these data and from the observation that HCG increases the PFC response also in nude female mice, HCG probably acts on T [thymus-derived] and B [bone marrow-derived] cells.