Identification of a benzo[a]pyrene-like binding protein involved in circulating immune complexes of patients with mammary tumors

Anti-benzo[a]pyrene (B[a]P)-like autoantibodies (autoAb) have been characterized in sera of patients with epithelial tumors. Circulating immune complexes (CIC) from these sera have been analysed after polyacrylamide gel electrophoresis (PAGE) under non-denaturing conditions. Immunoblotting was performed using a monoclonal antiidiotypic antibody (Ab), internal image of conjugated B[a]P called AIB1 and anti-human immunoglobulins (Ig). An immunoreactivity was seen only with AIB1 Ab, suggesting the presence of a ‘B[a]P-like’ binding protein. Additional studies showed that this immunoreactivity is not associated with an 18- to 20-kDa protein previously identified in the same CIC.