Prenatal exposure of balb/c mice to ochratoxin A: Effects on the immune system in the offspring

Abstract

Effects of prenatal exposure to the mycotoxin ochratoxin A (OA) on the immune system were evaluated in Balb/c mice. Dams were exposed to OA in their diet at doses of 0.18 (control), 30 or 200 μg/kg before and during gestation. At birth, pups were cross-fostered to non-exposed dams. OA exposure of the dams did not influence reproductive outcome, that is, the numbers of litters, litter sizes and body weight of the pups. Flow cytomety analysis of T-lymphocyte subpopulations on days 14 and 28 postpartum revealed a decrease in the percentages of splenic CD4 + and CD8 + cells in offspring from the high-dose group (200μg/kg diet), but no significant alterations in absolute numbers of these cell populations nor in the total numbers of splenocytes were observed. In the thymus, a relative as well as an absolute increase in the CD4 + subpopulation was seen in exposed pups on day 14. On day 28, the absolute numbers of CD4 +, CD8 + and CD4 +CD8 + (double positive) cells were increased, reflecting an elevated number of thymocytes in the high-dose group. No significant differences were found in the proliferative responses of splenic or thymic lymphocytes to mitogens, or in the production of interleukin-2 in concanavalin A-stimulated cell cultures. Further, the plaque-forming cell response to sheep red blood cells and the humoral antibody response to the viral antigen PR8 were not affected by prenatal exposure to OA. No significant differences in natural killer cell activity were observed. The results indicate that exposure of dams to relatively low levels of dietary OA alters absolute and relative numbers of lymphocyte subpopulations in lymphoid organs, but does not suppress immune functions in the offspring.