Suppression of antibody response of male mice exposed to diethylstilbestrol or estramustine phosphate (Estracyt).

The effects of treatment of male mice with diethylstilbestrol (DES) or estramustine phosphate (EMP) on the primary antibody response to sheep red blood cells (SRBC) and lipopolysaccharide (LPS) were investigated using a hemolytic plaque assay for enumeration of antibody-producing cells. DES treatment at a daily dose of 1.4 or 5.6 mg/kg from 2 days prior to and up to 3 days after immunization significantly reduced the number of anti-SRBC as well as anti-LPS-producing cells per 10(6) spleen cells. The 100 mg/kg EMP given as daily intraperitoneal injections significantly diminished the antibody response to both SRBC and LPS. No alteration in the number of anti-SRBC-producing cells per 10(6) spleen cells was detected in spleens from mice receiving 30 mg/kg/day EMP, while the number of anti-LPS-producing cells was reduced. The immunoregulatory effects of EMP are apparently not a pure estrogen effect, since treatment with doses of estradiol-17 beta equivalent to the amounts of estradiol linked to the cytotoxic moiety in 100 mg/kg/day of EMP were without effect. EMP-induced functional impairment in the T-cell population is inferred from the reduced ability of adoptively transferred T cells from EMP-exposed animals to support an antibody response to SRBC in syngeneic nude mice.