IDENTIFICATION OF A UNIQUE FORM OF P53 IN HUMAN CORD-BLOOD ASSOCIATEDWITH THE DEVELOPMENT OF MATERNAL AUTOANTIBODIES

PROBLEM: The possible link between p53-reactive antibodies in multipar ous women and exposure to a unique p53 protein during pregnancy was ex amined. METHOD OF STUDY: p53-reactive antibodies were evaluated in ser a from nulligravid and multiparous women and patients with ovarian can cer by Western immunoblot. Furthermore, the presence of p53 protein wa s assayed in cord blood by enzyme-linked immunosorbent assay. Cord blo od-derived p53 was compared structurally by protein fingerprinting and functionally by gel mobility shift assay to other isolates of p53. RE SULTS: Antibodies reactive with wild-type p53 were observed in 92% of multiparous women and 42% were reactive with one tumor-derived p53 pro tein. p53 protein was detected in 27 of 154 samples of cord blood. Str uctural analysis indicated that the fetal p53 resembled the UL-1 p53. Functionally, the fetal and UL-1 proteins failed to bind DNA. CONCLUSI ONS: Fetal p53 protein seems to be distinct from wild-type p53, charac terized by enhanced stability, structural differences and inability to bind DNA, analogous to alternatively spliced variants. Exposure to fe tal p53 protein may form the basis for immunologic protection against cancer induced by multiparity.