[Enhanced inhibition of splenic lymphocyte proliferation by 2,3,7,8-tetrachlorodibenzo-p-dioxin in C57B1/10 (Ah+Ah+) mice compared to DBA/2 (AhAh) mice].

In concanavalin A-treated cultures TCDD (10(-8)M) inhibited proliferation of mouse spleen lymphocytes in cells of C57B1/10/mice by 65% and in cells of DBA/2 mice--by 42%. In phytohaemagglutinin-treated cultures of spleen lymphocytes of both strains TCDD produced no significant decrease in incorporation of 3H-thymidine into DNA. These observations indicate that effects of TCDD on lymphocyte proliferation are mediated by pleiotropic activity of Ah gene.