title: Paradoxical effects of cadmium exposure on antibacterial antibody responses in two fish species: inhibition in cunners (Tautogolabrus adspersus) and enhancement in striped bass (Morone saxatilis).
abstract: Previous work in a marine fish, the cunner (Tautogolabrus adspersus), showed that endocytosis of bacteria by cells in the liver and spleen was affected by 96-h exposure of the fish to cadmium at a concentration of 12 micrograms/ml; however, antibody response to sheep erythrocytes was not affected. Since the latter finding was questionable because of short immunization times, and data from more than a single fish species were desirable, both the cunner and an anadromous fish, the striped bass (Morone saxatilis), were examined for antibody responses against the bacterium Bacillus cereus in Freund's complete adjuvant during a 6- to 8-wk time period. Exposure to 12 micrograms/ml cadmium caused significant inhibition of serum antibody titers (P less than 0.007) in cunners. Paradoxically, antibody response in striped bass exposed to 10 micrograms/ml cadmium was enhanced sixfold. This enhancement was weaker but still evident when the antigen was injected 48 d after cadmium exposure. Peritoneal exudate cells from cadmium-exposed striped bass also showed more active migration through microporous filters than cells from non-exposed fish. Since the 96-h cadmium LC50 was 26 micrograms/ml for cunners and 20 micrograms/ml for striped bass, the differences in antibody response could not be explained on the basis of differences in cadmium toxicity. Although geometric mean liver cadmium levels after exposure at 15 degrees C were higher in cunners (163.8 +/- 1.2 micrograms/gm) than in striped bass (64.4 +/- 1.2 micrograms/g), cunners exposed to cadmium at 2 degrees C had lower cadmium levels (46.4 +/- 1.2 micrograms/g) which were still effective in inhibiting antibody production at 8 degrees C. On the other hand, striped bass not exposed to cadmium showed a strong, exponential rise in serum antibody when the temperature at immunization, 14 degrees C, was reduced to 9 degrees C; whereas cunners held in the same tanks exhibited a weaker, biphasic serum antibody response. Regardless of the cause (innate differences in cellular response, or better stress adaptability in an anadromous fish), the data show that chemical-stress effects on the immune system of one fish species cannot be extrapolated to another species.
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis*; D000917:Antibody Formation / Q000187:drug effects*; D001409:Bacillus cereus / Q000276:immunology*; D002104:Cadmium / Q000494:pharmacology*; D002465:Cell Movement / Q000187:drug effects; D005122:Exudates and Transudates / Q000166:cytology; D005399:Fishes / Q000276:immunology*; D010529:Peritoneal Cavity / Q000166:cytology; D013045:Species Specificity
chemical_list: D000907:Antibodies, Bacterial; D002104:Cadmium