title: Alternative forms of a strain-specific neutralizing antigenic site on the Sindbis virus E2 glycoprotein.
abstract: Experiments with monoclonal antibodies raised against two laboratory strains of Sindbis virus, SB and SIN, suggested the existence of a strain-specific neutralizing antigenic site (E2-b) on the E2 glycoprotein. A comparison of monoclonal antibody binding patterns and E2 glycoprotein gene sequences of six laboratory strains distinguished three different configurations of E2-b that correlated with specific amino acid substitutions at position 216 of the E2 glycoprotein. Further study of neutralization escape mutants selected with E2-b-specific antibodies confirmed that amino acid 216 is a major determinant of the E2-b antigenic site. Eight of nine mutants showed a coding change at position 216. One neutralization escape mutation created a new glycosylation site at position 213 and resulted in an E2 protein with an altered migration rate in SDS-PAGE. The neutralization escape mutants studied included amino acid substitutions not found in the laboratory strains that revealed differing binding requirements for two E2-b-specific monoclonal antibodies. The E2-b site is contrasted with the E2-c neutralizing antigenic site described previously (R.A. Olmsted, W.J. Meyer, and R.E. Johnston, 1986, Virology 148, 245-254).
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000956:Antigens, Viral / Q000276:immunology*; D001483:Base Sequence; D001667:Binding, Competitive; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D005814:Genes, Viral; D006023:Glycoproteins / Q000235:genetics / Q000276:immunology*; D009154:Mutation; D012367:RNA, Viral / Q000235:genetics; D012845:Sindbis Virus / Q000235:genetics / Q000276:immunology*; D013045:Species Specificity; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000956:Antigens, Viral; D000939:Epitopes; D006023:Glycoproteins; D012367:RNA, Viral; D014759:Viral Envelope Proteins