Epstein-Barr Virus/Complement Fragment C3d Receptor (CR2) Reacts with p53, a Cellular Antioncogene-Encoded Membrane Phosphoprotein: Detection by Polyclonal Anti-Idiotypic Anti-CR2 Antibodies

• Published in: Proceedings of the National Academy of Sciences - PNAS 1989-12, Vol.86 (24), p.10054-10058
• Main Authors: Barel, Monique, Fiandino, Anny, Lyamani, Fouad, Frade, Raymond
• Format: Article
• Language: English
• Subjects: Antibodies; Antigen-Antibody Complex; Antigens, Differentiation, B-Lymphocyte - immunology; Antigens, Differentiation, B-Lymphocyte - metabolism; B lymphocytes; Biological and medical sciences; Cell Line; Cell lines; Cell Membrane - immunology; Cell membranes; Cell nucleus; Cellular immunity; Complement C3d - metabolism; Fundamental and applied biological sciences. Psychology; Herpesvirus 4, Human - metabolism; Humans; Immunoblotting; Immunoglobulin Idiotypes - immunology; Intracellular membranes; Isoelectric Focusing; Ligands; Membrane proteins; Microbiology; Molecular Weight; Nuclear Proteins - metabolism; Oncogene Proteins - genetics; Oncogene Proteins - isolation & purification; Oncogene Proteins - metabolism; Oncogenes; Phosphoproteins - genetics; Phosphoproteins - isolation & purification; Phosphoproteins - metabolism; Phosphorylation; Receptors, Complement - immunology; Receptors, Complement - metabolism; Receptors, Complement 3d; Replicative cycle, interference, host-virus relations, pathogenicity, miscellaneous strains; Tumor Suppressor Protein p53; Virology
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.86.24.10054

Epstein--Barr virus and the C3d fragment of the third component of complement are specific extracellular ligands for complement receptor type 2 (CR2). However, intracellular proteins that react specifically with CR2 and are involved in post-membrane signals remain unknown. We recently prepared polyclonal anti-idiotypic anti-CR2 antibodies (Ab2) by using the highly purified CR2 molecule as original immunogen. We showed that Ab2 contained anti-idiotypic specificities that mimicked extracellular domains of CR2 and detected two distinct binding sites on CR2 for its specific extracellular ligands, Epstein--Barr virus and C3d. We postulated that Ab2 might also contain specificities that could mimic intracellular domains of CR2. Here we report that Ab2, which did not react with Raji B-lymphoma cell surface components, detected specifically, among all components solubilized from Raji cell membranes, a single intracellular membrane protein of apparent molecular mass of 53 kDa. This protein was identified as the p53 cellular antioncogene-encoded membrane phosphoprotein by analyzing its antigenic properties with Pab1801, a monoclonal anti-p53 antibody, and by comparing its biochemical properties with those of p53. Additionally, solubilized and purified CR2 bound to solubilized p53 immobilized on Pab1801-Sepharose. p53, like CR2, was localized only in purified plasma membranes and nuclei of Raji cells. These data suggest strongly that p53, a cellular antioncogene-encoded phosphoprotein, reacted specifically with CR2 in Raji membranes. This interaction may represent one of the important steps through which CR2 could be involved in human B-lymphocyte proliferation and transformation.