Effects of a single dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin, given at post-puberty, in senescent mice.
2,3,7,8-Tetrachlorodibenzo-p-dioxin is a well-known immunosuppressive environmental pollutant. TCDD interferes with physiological signaling of the arylhydrocarbon receptor, leading to cell-specific changes in gene transcription and cell differentiation. With respect to the immune system, the T-cell lineage and B-cell lineages are particularly affected. Although a single dose given to mice is excreted within weeks, these changes in differentiation may have long-term consequences for immune competence. We studied the effects of a single dose of TCDD given to young mice on some parameters of their immune system after they had aged almost to the end of their lifespan. Groups of 15 mice were given either 2.5 microg TCDD/kg b.w. or 25 microg TCDD/kg b.w. at the age of 8-12 weeks, and were analyzed between 16 and 21 months of age. Survival was equal in all groups. Blood glucose levels did not differ, and glucose tolerance after oral challenge was normal in old control mice and TCDD-exposed mice. No differences in the frequencies of B-cells, T-cells, or NK-cells were detectable. TCDD-exposed mice at both doses had a significantly higher titer of IgM compared to controls. Histological examination of pancreas, liver, kidney, spleen, and lungs yielded no differences, except for the lungs, where a significantly higher number of animals displayed activated BALT. In conclusion, our data suggest that a single dose of TCDD in young mice is correlated to activated secondary lymphoid tissues and high IgM titers. Both findings are congruent with a weakened immune system.
Esser
Charlotte
C
Institute of Environmental Research gGmbH, University of Düsseldorf, Auf'm Hennekamp 50, 40225 Düsseldorf, Germany. chesser@uni-duesseldorf.de
Steinwachs
Swantje
S
Herder
Christian
C
Majora
Marc
M
Lai
Zhi-Wei
ZW
D000375:Aging / Q000187:drug effects / Q000276:immunology* / Q000473:pathology; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D001786:Blood Glucose / Q000187:drug effects / Q000276:immunology; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D007107:Immune System / Q000187:drug effects* / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007274:Injections, Intraperitoneal; D007694:Killer Cells, Natural / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D008168:Lung / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D018655:Lymphocyte Count; D008221:Lymphoid Tissue / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D009928:Organ Specificity / Q000187:drug effects / Q000276:immunology; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology
D001786:Blood Glucose; D004785:Environmental Pollutants; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D000072317:Polychlorinated Dibenzodioxins