EFFECT OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD) ON HUMAN LYMPHOCYTE MATURATION

The effect of TCDD on lymphocyte activation and proliferation in response to either endogenously produced or exogenously added cellular growth factor(s) was investigated. TCDD effectively reduced proliferation of either freshly prepared or activated T-cells when stimulated with either phytohemagglutinin (PHA-M) and/or recombinant human IL-2 (rIL-2) respectively. Similarly, both freshly activated or preactivated human B-cells with antihuman IgM demonstrated a reduced response to partially purified B-cell growth factor (BCGF) in the presence of TCDD. Also, the synthesis of IL-2 by PHA-M activated T-cells or IgM by PWM stimulated B-cells (in the presence of syngeneic T-cells) was decreased by TCDD. The observed effects of TCDD were concentration dependent and support the conclusion that the xenobiotic is an immunosuppressive agent.