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Immune Function and Cytochrome P4501A Activity after Acute Exposure to 3,3′,4,4′,5‐Pentachlorobiphenyl (PCB 126) in Channel Catfish
Author(s) -
Rice Charles D.,
Schlenk Daniel
Publication year - 1995
Publication title -
journal of aquatic animal health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 52
eISSN - 1548-8667
pISSN - 0899-7659
DOI - 10.1577/1548-8667(1995)007<0195:ifacpa>2.3.co;2
Subject(s) - ictalurus , immune system , catfish , edwardsiella ictaluri , ictaluridae , biology , medicine , endocrinology , antigen , humoral immunity , immunology , fish <actinopterygii> , fishery
Several commercial polychlorinated biphenyl (PCB) mixtures reduce immune functions in fish. However, little is known about the effects of specific coplanar PCBs on immune functions in fish. We investigated the effects of a single, acute exposure to either corn oil as a carrier control or 0.01, 0.1, and 1.0 mg/kg body weight of 3,3′,4,4′,5‐pentachlorobiphenyl (PCB 126) on both nonspecific cellular immune responses and antigen‐specific humoral immune responses in channel catfish Ictalurus punctatus . Fish were given PCB 126 intraperitoneally, and innate cellular immune responses were evaluated 3 and 7 d later. The humoral immune response against Edwardsiella ictaluri was evaluated 14 d after treatments. Immunological results were compared to cytochrome P4501A induction, ethoxyresorufin O ‐deethylase (EROD) activity, allometric indices, and hematology as biomarkers of exposure and effects 3 and 7 d posttreatment. Cytochrome P4501A and EROD activity were induced by all three doses of PCB 126, whereas allometric indices, peripheral blood hematocrits, and mononuclear cell percentages were relatively unaffected at all doses. Nonspecific cytosoxic cell activity was reduced only at the highest dose. Phagocyte oxidative burst was reduced in 0.1 mg/kg treated fish on day 7 and in 1.0 mg/kg treated fish on days 3 and 7. This effect at 0.1 mg/kg coincided with maximum induction of cytochrome P4501A, thereby serving as an equally sensitive marker. The humoral response to E. ictaluri , measured by quantifying antigen‐specific antibody‐secreting cells, increased following exposure to 0.01 mg/kg but was unaffected by higher doses. Unlike the case in rodent models, coplanar PCB exposures in fish appear to negatively affect innate immune responses in comparison to humoral responses.