CHARACTERIZATION OF GENOTYPE-SPECIFIC EPITOPES OF THE HN PROTEIN OF MUMPS-VIRUS

The SBL-1 strain of mumps virus, grouping with genotype A on the basis of the small hydrophobic protein gene sequence, was grown in the pres ence of three different monoclonal antibodies, The monoclonal antibodi es were directed against the haemag-glutinin-neuraminidase (HN) protei n and they inhibited haemagglutinating activity and infectivity of the virus, The HN genes of the nine neutralization-escape virus mutants w ere sequenced and the predicted amino acid sequences were compared wit h that of the parental virus. Amino acid substitutions were found at p ositions 269, 352 and 354, respectively, of the 582 amino acid long pr otein. The three monoclonal antibodies did not react with 35 virus str ains isolated in Stockholm during the years 1970 to 1985, Thirteen and four of the strains were found to belong to the D and C genotypes, re spectively, A type-specific neutralization antibody response was also found in sera of rabbits hyperimmunized with purified virions of genot ype A and D, The genotype-specific difference in neutralizing activity in mice and rabbits was not corroborated by an overall difference in the amino acid sequence of the HN protein of the different genotypes, Further studies are needed to explore the efficacy of mumps virus vacc ines for protection against homologous and heterologous genotypes of m umps virus.