Effects of single exposure to cadmium on the primary humoral antibody response.

Effects of a single intraperitoneal (i.p.) injection of cadmium (Cd) on the primary humoral antibody responses against sheep red blood cells (SRBC) in mice were studied by assaying splenic plaque forming cells (PFC). PFC responses in mice were suppressed when exposed to Cd 2 days after immunization, and inconsistently stimulated when exposed before immunization. Dose-response relationships were observed in the suppressive effect of Cd exposure 2 days after immunization, but not consistently in the stimulative effect of Cd exposure before immunization. Thymus weights and cell numbers decreased markedly 4 days after Cd exposure with or without the antigenic stimulus. Splenic weights increased 2 days after Cd exposure, while the number of spleen cells was dramatically decreased 1 days after Cd exposure and still remained below normal 2 days after exposure.