[Effects of chorionic gonadotropin on dynamics of primary immune response]

The effect of chorionic gonadotropin (CG) on primary immune response was estimated according to the level of direct and indirect plaque-forming cells (PFC) on day 5, 8 and 12 after immunization of non-castrated and ovariectomized female mice of CBA strain. It was established, that on the 5th day CG (40-200 IU) did not influence the direct PFC level in ovariectomized animals, but stimulated them in non-ovariectomized mice (40 IU). In ovariectomized animals the selective immunodepressive effect of hormone on the IgG-PFC formation processes has been revealed. The CG effect depended on the time of PFC number examination as well as on the hormone dose. In non-castrated animals, where immunomodulating CG effects are partially mediated by ovarian hormones, the injection of hormone only in the dose of 200 IU significantly lowered the number of IgM and IgG-PFC. It is suggested, that sex steroids on the late stages of PFC formation, when the processes of isotype antibody synthesis switch take place, appear to be synergists of CG immunodepressive effect.