Differential immunotoxic effects of the environmental chemical benzo[a]pyrene in young and aged mice.

Young (3-6 months), middle-aged (16-18 months) and aged (23-26 months) mice were exposed in vitro and in vivo to the immunotoxic environmental chemical benzo[a]pyrene. The generation of antibody producing cells to the T-dependent antigens of sheep erythrocytes was observed to be suppressed in all age groups. Significantly, aged mice were shown to exhibit a greater percent suppression of antibody responses than young or middle-aged mice both in vitro and in vivo. The results presented provide the first evidence that the degree of immunological toxicity of environmental chemicals may be partially dependent upon the chronological and immunological age of the animal.