Identification and characterization of a specific autoantiphosphatidylinositol immune response during the time course of benzo(a)pyrene-induced malignant tumors in female Sprague-Dawley rats.

High levels of anti-phosphatidylinositol (PtdIns) autoantibodies (autoAb) have been previously described in sera of cancer patients and in plasma of dimethylbenzanthracene-treated female Sprague-Dawley rats. The presence of anti-PtdIns autoAb was tested in a model of highly malignant sarcomas induced by a single dose of benzo(a)pyrene [B(a)P] diluted in sesame oil and injected in female Sprague-Dawley rats. Significantly elevated levels of anti-PtdIns autoAb were found in sera of B(a)P-treated rats 40 days after B(a)P administration, whereas no significant levels of anti-PtdIns autoAb were noted in oil- or benzo(e)pyrene-treated rats. After day 60, autoantibody levels plateaued in B(a)P-treated rats, and highly malignant sarcomas appeared with 100% efficiency around day 100. Anti-PtdIns autoAb avidity and specificity were found to be high.