Antigenic and genetic characterization of the fusion (F) protein of mumps virus strains

Twelve strains of mumps virus, belonging to the A, C and D genotypes of the small hydrophobic (SH) protein gene, were investigated by nucleotide seque ncing of the fusion protein gene. The nucleotide sequences and deduced amin o acid sequences were aligned and compared with previously reported sequenc es of the gene. In addition an antigenic comparison between the F protein o f different strains of the A, C and D genotypes was performed with ten mono clonal antibodies directed against the F protein of genotype A. Phylogeneti c analysis of the coding region of the F gene showed the expected clusterin g of the different genotypes, as previously determined from the SH protein gene. Comparison of the 538 long amino acid sequence of the protein showed that only a small number of amino acids differed between the viral strains. The A genotype differed fi-om B, C and D whereas the latter showed fewer c onsistent amino acid differences between themselves. Nine of the ten monocl onal antibodies reacted with the C and D genotypes and one failed to react with these genotypes. It is concluded that the structure and antigenicity o f the F protein is well conserved both intra- and intergenotypically over l ong periods of time.