title: A conserved coronavirus epitope, critical in virus neutralization, mimicked by internal-image monoclonal anti-idiotypic antibodies.
abstract: Monoclonal antibody (MAb) 6A.C3 neutralizes transmissible gastroenteritis coronavirus (TGEV) and is specific for a conserved epitope within subsite Ac of the spike (S) glycoprotein of TGEV. Six hybridomas secreting anti-idiotypic (Ab2) MAbs specific for MAb 6A.C3 (Ab1) have been selected. All six MAbs inhibited the binding of Ab1 to TGEV and specifically cross-linked MAb1-6A.C3. Four of these hybridomas secreted gamma-type anti-idiotypic MAbs. The other two Ab2s (MAbs 9A.G3 and 9C.E11) were recognized by TGEV-specific antiserum induced in two species. This binding was inhibited by viruses of the TGEV group but not by serologically unrelated coronaviruses. These results indicate that MAb2-9A.G3 and MAb2-9C.E11 mimic an antigenic determinant present on the TGEV surface, and they were classified as beta-type ("internal-image") MAbs. TGEV-binding Ab3 antiserum was induced in 100% of mice immunized with the two beta-type MAb2s and in 25 to 50% of mice immunized with gamma-type MAb2. Both beta- and gamma-type Ab2s induced neutralizing Ab3 antibodies in mice that were mainly directed to antigenic subsite Ac of the S protein.
authors.affiliation: Centro de Biología Molecular, Universidad Autónoma, Canto Blanco, Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Suñé
authors.forename: C
authors.initials: C
authors.lastname: Smerdou
authors.forename: I M
authors.initials: IM
authors.lastname: Antón
authors.forename: P
authors.initials: P
authors.lastname: Abril
authors.forename: J
authors.initials: J
authors.lastname: Plana
authors.forename: L
authors.initials: L
authors.lastname: Enjuanes
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D000936:Antigen-Antibody Complex; D000956:Antigens, Viral / Q000032:analysis / Q000276:immunology*; D003332:Coronaviridae / Q000276:immunology*; D016765:Coronavirus, Feline / Q000276:immunology; D000939:Epitopes / Q000032:analysis*; D006801:Humans; D006825:Hybridomas / Q000276:immunology; D007700:Kinetics; D006517:Murine hepatitis virus / Q000276:immunology; D009500:Neutralization Tests; D013045:Species Specificity; D005760:Transmissible gastroenteritis virus / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000956:Antigens, Viral; D000939:Epitopes