Effects of lead, cadmium and methylmercury on immunological memory.

The memory response of lymphocytes to antigen was altered in mice exposed to lead, cadmium, or methylmercury. Both lead (1300 ppm) and methylmercury(10 ppm) impaired the memory response while cadmium (300 ppm) stimulated memory. Memory was significantly affected only at the largest dosages where toxic signs were generally detected. The lower dosages did not affect the memory of lymphocytes which produce antibody. These data suggest that the T lymphocyte rather than the B lymphocyte is the cell affected when the secondary immune response is altered after exposure to subclinical amounts of these environmental contaminants.