Acutely administered polychlorinated biphenyls (PCBs) decrease splenic cellularity but increase its ability to cause...

A single intraperitoneal injection of 1000 mg/kg body weight of a PCB mixture (Aroclor 1242) to adult male BALB/cc mice caused not only a relative spleen enlargement, but also an absolute spleen lymphocyte depletion. However, there was an enrichment of spleen T cells necessary to cause a graft-versus-host reaction (GVHR) in (C3H x BALB/c) F1 neonates. The effect was present 6 days after PCB administration and was no longer present on days 12-13. These studies suggest a transient effect of acutely administered PCBs on splenic lymphocytes (B cells, null cells, some T cells) other than mature GVH inducing T cells. The effect may be either similar to or possibly indirectly mediated by corticosteroids.