Evidence for human antibodies that recognize an aflatoxin epitope in groups with high and low exposure to aflatoxins.

Antibody activity against an aflatoxin epitope has been detected in serum from individuals who live in Kenya and who experience high exposure to aflatoxin B1. The activity was higher than in Danish people. The highest antibody activity was found in individuals who were recently exposed to aflatoxin B1. The ratio between IgG and IgM activities was higher in individuals with a high antibody titer. The specificity of the antibody activity differed in the serums obtained from Danish and Kenyan persons ("Danish" and "Kenyan" serum, respectively). The activity in Danish serum was inhibited by an aflatoxin-like substance isolated from human urine, whereas aflatoxin B1 did not inhibit the activity. In contrast, the activity in Kenyan serum was not inhibited by the aflatoxin-like substances. Therefore, the presence of antibodies against aflatoxin in humans indicates exposure to aflatoxin or aflatoxin-antigenic material. However, the biological consequences of these antibodies remain unknown.