2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) inhibits the activation of antigen-specific T-cells in mice.
There are conflicting data in the literature regarding target cells in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced immunotoxicity. In the present study, adult male C57BL/6 mice were exposed to TCDD (50 micrograms/kg) 4 days prior to immunization with ovalbumin (OVA). The effect of TCDD on the specific immune response in vivo was determined by T-cell proliferation and IL-2 production in response to either OVA or anti-mouse-CD3 antibodies plus PMA in vitro. The antigen-specific T-cell proliferation and IL-2 production in response to OVA were significantly suppressed by TCDD, while the polyclonal response to anti-CD3 antibodies plus PMA was not affected. This indicates that even at a high dose of TCDD the intra T-cell signalling pathways in resting cells are not disturbed, but TCDD selectively impairs the antigen-specific activation of T-cells. Since activated T-cells are required in antibody responses to T-dependent antigens, the low number of such cells observed in the present study, may well explain the suppressive effects of TCDD on humoral immunity reported previously.
Lundberg
K
K
Department of Toxicology, Uppsala University, Sweden.
Dencker
L
L
Grönvik
K O
KO
D000818:Animals; D002478:Cells, Cultured; D007274:Injections, Intraperitoneal; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D000072317:Polychlorinated Dibenzodioxins / Q000008:administration & dosage / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D014316:Tritium
D007376:Interleukin-2; D000072317:Polychlorinated Dibenzodioxins; D014316:Tritium