title: Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on maternal immune response during pregnancy.
abstract: Whether pregnancy-induced immunosuppression when combined with exposure to 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) could exacerbate immunotoxicity has not been previously investigated. The current study evaluated the immune status of C57BL/6 pregnant and virgin mice following exposure to TCDD. To this end, syngeneically pregnant or virgin female mice were injected intraperitoneally with 10 micro g/kg TCDD. Pregnancy alone significantly decreased thymic cellularity and J11d expression as well as induced changes in T-cell subsets. TCDD treatment caused significant thymic atrophy in pregnant mice as early as 48 h after exposure, but this effect was apparent in virgin mice only after 72 h. TCDD treatment also caused more marked alterations in thymic T-cell subpopulations of pregnant mice when compared to the virgin mice, with a decrease in the percentage of double-positive T cells and an increase in the percentage of single-positive (sP CD4(+) or sP CD8(+)) and double-negative T cells. Moreover, the proliferative responses of thymocytes, but not splenocytes, to mitogens were significantly altered in TCDD-treated pregnant mice when compared to the TCDD-treated virgin mice. Furthermore, no significant changes in the expression of CD4, CD8, B220 and NK1.1 markers were found in splenocytes from TCDD-treated virgin and pregnant mice. Immunization of mice with a superantigen caused a similar immunotoxic response in TCDD-treated pregnant and virgin mice with a decreased lymph node cellularity and lower percentages and cell numbers of Vbeta3(+) and Vbeta11(+) T cells. Together, the results of the current study demonstrate for the first time that pregnancy augments the sensitivity to TCDD-induced immunotoxicity in the thymus, but not in secondary lymphoid organs.
authors.affiliation: Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298, USA.
authors.forename: Iris A
authors.initials: IA
authors.lastname: Camacho
authors.forename: Mitzi
authors.initials: M
authors.lastname: Nagarkatti
authors.forename: Prakash S
authors.initials: PS
authors.lastname: Nagarkatti
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D004768:Enterotoxins / Q000494:pharmacology; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D005434:Flow Cytometry; D007107:Immune System / Q000187:drug effects* / Q000276:immunology; D007274:Injections, Intraperitoneal; D051379:Mice; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects* / Q000276:immunology; D012746:Sexual Abstinence; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects / Q000276:immunology
chemical_list: D004768:Enterotoxins; D004785:Environmental Pollutants; D000072317:Polychlorinated Dibenzodioxins; C026066:enterotoxin A, Staphylococcal