© 1990 Oxford University Press
research-article |
Immunological detection of in vivo aflatoxin B1–DNA adduct formation in rats, rainbow trout and coho salmon
Department of Experimental Pathology, Cancer Institute Kami-Ikebukuro, Toshima-ku, Tokyo 170, Japan
2To whom reprint requests should be sent
Immunological detection of carcinogen-DNA adducts in organs or tissues should prove a particularly useful approach for monitoring carcinogen exposure, for characterization of carcinogen binding to DNA and for investigating DNA repair processes in vivo. In one of a series of experiments aimed at raising antibodies against several carcinogen-modified DNAs, rabbits were immunized in our laboratory with aflatoxin B1 (AFB1)-Modified DNA. After thetiter and specificity of the antibodies produced were checked against standards by the enzyme-linked immunosorbent assay (ELISA) method, they were used to investigate DNA extracted from livers of rats and rainbow trout (Salmo mykiss) injected with tritiumlabeled AFB1 at doses of 1–2 mg/kg (rats) or 0.1–0.5 mg/kg (rainbow trout). Adduct levels were compared using both radioactivity and ELLSA methods. Positive DNA binding could bedetected in both rats and rainbow trout by the immunological method at similar levels to those estimated with the radioactive analysis. To throw light on possible mechanisms underlying the wide variation in response to aflatoxins among salmonidfish, DNA extracted from the livers of rainbow trout (susceptible species) and coho salmon (Oncorhynchus kisutch) (less susceptible species) were compared following AFB1 treatment. A high rate of DNA binding was observed in rainbow trout, whereas significantly lower values were evident in coho salmon, suggesting a direct relationship between binding levels and susceptibility to mycotoxin carcinogenicity.