Presence of CD4(+) SP and DP (gammadelta, alphabeta) T-Cells Expressing BPDE-DNA Adducts in Progeny of Mouse Dams Exposed to Benzo(alpha) pyrene at Mid-Gestation

The detoxification ability of sex-role reversed seahorses determines the sexual dimorphism in immune responses to benzo[a]pyrene exposure

Sexual dimorphism in immune responses is an essential factor in environmental adaptation. However, the mechanisms involved remain obscure owing to the scarcity of data from sex-role-reversed species in stressed conditions. Benzo[a]pyrene (BaP) is one of the most pervasive and carcinogenic organic pollutants in coastal environments. In this study, we evaluated the potential effects on renal immunotoxicity of the sex-role-reversed lined seahorse (Hippocampus erectus) toward environmental concentrations BaP exposure. Our results discovered the presence of different energy-immunity trade-off strategies adopted by female and male seahorses during BaP exposure. BaP induced more severe renal damage in female seahorses in a concentration-dependent manner. BaP biotransformation and detoxification in seahorses resemble those in mammals. Benzo[a]pyrene-7,8-dihydrodiol-9,10-oxide (BPDE) and 9-hydroxybenzo[a]pyrene (9-OH-BaP) formed DNA adducts and disrupted Ca2+ homeostasis may together attribute the renal immunotoxicity. Sexual dimorphisms in detoxification of both BPDE and 9-OH-BaP, and in regulation of Ca2+, autophagy and inflammation, mainly determined the extent of renal damage. Moreover, the mechanism of sex hormones regulated sexual dimorphism in immune responses needs to be further elucidated. Collectively, these findings contribute to the understanding of sexual dimorphism in the immunotoxicity induced by BaP exposure in seahorses, which may attribute to the dramatic decline in the biodiversity of the genus.

Alterations in CD4+, CD8+, Vgamma3, Vgammadelta, and/or Valpha betaT-lymphocyte expression in lymphoid tissues of progeny after in utero exposure to benzo(alpha)pyrene

That benzo alpha)pyrene (Balpha P) decreases both humoral and cell-mediated immunity, and leads to increases in progeny tumor development after in utero insult, suggests that T- and B-lymphocytes are made defective in exposed offspring. In the study here, C3H mice were injected once with Balpha P (150 microg/g BW) at day 12 of pregnancy and progeny lymphoid tissues were excised during gestation (day 18; GD18) or at 1 or 6 weeks post-partum. The isolated lymphoid cells were analyzed by flow cytometry/immunofluorescence or assessed for function. In Balpha P-exposed fetuses, thymic Thy1(+) cell levels were decreased (relative to levels in organs of corn oil-exposed dam progeny). In addition, for up to 6 weeks post-birth, CD4(+)CD8(+) (double positive; DP) cells were virtually absent and levels of CD4(-)CD8(-) (double negative; DN) cells were consistently at epsilon 90%. With regard to single positive (SP) cells, CD4(+) cell levels were also decreased in tissues at GD18 up through 6 weeks post-birth; CD8(+) cell levels were increased, but only in pups at 1-week and 6-weeks post-birth. In 1-week-old progeny, spleen CD8(+) cell levels were quantitatively unchanged, though CD4(+) levels were reduced 2-4-fold and CD4(-)CD8(-) DN levels significantly increased. With respect to TCRs, fetal levels of thymic CD3Vgamma(3)(+) and CD3Vgamma delta(+) cells were decreased; levels of CD3Valphabeta cells were only slightly depressed. The latter results contrast sharply with a strong reduction in CD3Valphabeta cells in the fetal livers of Balpha P-exposed progeny. Interestingly, these livers also strongly evidenced a presence of BalphaP-7,8-dihydrodiol-9,10-epoxide metabolite. When assessed for any change in function, the CD4(+), Thy1(+) cells isolated from Balpha P-exposed progeny tissues responded weakly (relative to controls) to ConA and in an allogeneic MLR. Taken in totality, the results here strengthen our original hypothesis that BalphaP can create a favorable milieu for tumor growth progression in progeny of exposed mothers by affecting development of sufficient numbers of functional lymphocytes in the offspring.