Effect of dam's accumulated tissue PCBs on mouse filial T-cell population and T-cell subpopulations

Abstract

Polychlorinated biphenyls (PCBs) are environmental contaminants that have been shown to alter the immune status of experimental animals. Accidental exposures to PCBs in humans also have been shown to affect the immune system. In those studies, however, the effects of PCBs on immune response were not evaluated in immature immune systems, such as fetuses and sucklings. The immune system is differentiating during fetal development and the developing immune system may be more sensitive to xenobiotics. In the authors' previous reports, the transfer of PCBs by breast milk from the mouse body exceeded transplacental transfer by a factor 1000. However, the filial helper T-cell activity for IgG production was less suppressed in postnatally-exposed mice than in prenatally-exposed mice. Therefore, the suppression of helper T-cell activity for IgG production may be derived from the decrease in the number of helper T-cells or from the increase in the number of suppressor T-cells. The aim of the present investigation is to determine if PCBs accumulated in the dam's body alter the T-cell population and T-cell subpopulations in the thymus and spleen of filial mice.