title: Proliferative responses of harbor seal (Phoca vitulina) T lymphocytes to model marine pollutants.
abstract: In recent years, population declines related to viral outbreaks in marine mammals have been associated with polluted coastal waters and high tissue concentrations of certain persistent, lipophilic contaminants. Such observations suggest a contributing role of contaminant-induced suppression of cell-mediated immunity leading to decreased host resistance. Here, we assessed the effects of the prototypic polycyclic aromatic hydrocarbon (PAH), benzo[a]pyrene (B[a]P), and two polychlorinated biphenyls (PCBs), CB-156 and CB-80, on the T-cell proliferative response to mitogen in harbor seal peripheral lymphocytes. Despite the variability associated with our samples from free-ranging harbor seals, we observed a clear suppressive effect of B[a]P (10 uM) exposure on T cell mitogenesis. Exposures to 10 uM CB-156 and CB-80, and 1.0 and 0.1 uM B[a]P, did not produce significant depression in lymphoproliferation. Exposure to the model PAH at 10 uM resulted in a 61% (range 34-97%) average reduction in lymphoproliferation. We were able to rule out a direct cytotoxic effect of B[a]P, indicating that observed effects were due to altered T cell function. Based on our in vitro results, we hypothesize that extensive accumulation of PAH by top-trophic-level marine mammals could alter T cell activation in vivo and impaired cell-mediated immunity against viral pathogens.
authors.affiliation: Department of Environmental Toxicology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA. jcneale@ucdavis.edu
authors.forename: Jennifer C C
authors.initials: JC
authors.lastname: Neale
authors.forename: Judith A
authors.initials: JA
authors.lastname: van de Water
authors.forename: James T
authors.initials: JT
authors.lastname: Harvey
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Tjeerdema
authors.forename: M Eric
authors.initials: ME
authors.lastname: Gershwin
mesh_terms: D000818:Animals; D001564:Benzo(a)pyrene / Q000633:toxicity*; D002455:Cell Division / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D000922:Immunotoxins / Q000633:toxicity*; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D046048:Seals, Earless / Q000276:immunology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000922:Immunotoxins; D014874:Water Pollutants, Chemical; D001564:Benzo(a)pyrene; D011078:Polychlorinated Biphenyls