engleski

Molecular epidemiology and antigenic diversity of mumps virus

The mumps virus (MuV) molecular epidemiology is characterized by the co-circulation of numerous distinct strains. In the pre-vaccine era mumps was a common childhood disease but since the usage of live attenuated mumps vaccines became widespread, the number of cases dramatically declined. Still, despite the evidence of long-lasting immunity following vaccination, wild-type mumps viruses continue to circulate even in highly vaccinated populations. Standardized MuV phylogenetic analysis is based on the nucleotide sequence of the SH gene and the strains are placed into 11 genotypes, designated A-M. The recent mumps epidemics were mainly caused by the strains belonging to genotypes G and D. As the epidemiological analyses are based solely on the SH gene, they lack the information regarding differences in antigenic properties among various strains. The location of neutralization epitopes has been determined only for hemagglutinin-neuraminidase (HN). We performed multiple sequence comparisons of HN protein sequences in order to describe its diversity and plasticity, and to determine the level of similarity between vaccine and wild-type strains. The results of full-length HN protein phylogeny showed that MuV strains form a number of differing clades which are in concordance with grouping obtained by standard MuV genotyping. When vaccine strains are compared to all wild-type strains, the highest mean percentage of amino acid differences was found for Jeryl Lynn 5 and Jeryl Lynn 2 strains while the lowest value was obtained for Leningrad-3 and L-Zagreb strains. When only 3 antigenic regions of the HN protein, comprising 45 amino acids in total, were investigated, the diversity is considerably diminished: 51.5% of all strains show identical sequences (including vaccine strains L-Zagreb, Leningrad-3, Hoshino and Urabe). Another 26.5% (including Miyahara vaccine strain) differ in only 1 amino acid, while other strains differ in 2-5 amino acids from the most common sequence.

mumps; epidemiology; antigenic diversity

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