title: The receptor-binding and membrane-fusion properties of influenza virus variants selected using anti-haemagglutinin monoclonal antibodies.
abstract: A monoclonal antibody raised against X-31 influenza virus reacted with the majority of natural H3N2 viruses isolated between 1968 and 1982. A number of variants of X-31 and of a receptor-binding mutant of X-31 were selected by the antibody during virus replication in eggs and MDCK cells. Antibody-binding assays indicated that the viruses selected were not antigenic variants and analyses using derivatized erythrocytes showed that their receptor-binding properties differed from those of the parent viruses. The amino acid substitutions in the variants were all located in the vicinity of the receptor-binding site and the structural consequences are discussed in relation to the three-dimensional structure of X-31 HA. In addition all of the variants fused membranes at higher pH than wild-type virus indicating that structural modifications in the distal globular region of HA influence the low pH-induced conformational change required for membrane fusion.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D014644:Genetic Variation; D006385:Hemagglutination Inhibition Tests; D006389:Hemagglutinins, Viral / Q000235:genetics*; D009980:Influenza A virus / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D011991:Receptors, Virus / Q000502:physiology*; D013045:Species Specificity
chemical_list: D000911:Antibodies, Monoclonal; D006389:Hemagglutinins, Viral; D011991:Receptors, Virus