Genetic and phenotypic characterisation of mumps virus

Shorrock, Claire Ann (2001). Genetic and phenotypic characterisation of mumps virus. PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000f9b9

Abstract

Virological techniques have previously been used to investigate mumps virus (MuV) replication in vitro and have led to a rapid expansion of our understanding of this virus. The cell line of choice has been Vero cells, however, recent studies have concluded that variants of the original MuV are selected upon passage in Vero cells. The aim of this thesis is to describe the effect of cell substrate on MuVs through genotypic and phenotypic analysis after growth of MuVs in different host cells.
Data is presented which demonstrates that MuVs passaged in B95a or HeLa cells are of greater fitness than the parental Vero cell-grown viruses, when assayed to determine the titre of infectious virus produced. No adaptation period was required for growth of MuVs in B95a cells with the exception of one variant of the JL vaccine. An adaptation period was required for growth in HeLa cells. Only one of the viruses studied, a variant derived from Urabe vaccine, grew to a high inactivity titre in MRC-5 cells. Growth occurred after an initial adaptation period, suggesting a narrow bottleneck for virus growth in these cells and amino acid 431 in the HN protein is implicated in the adaptation to these cells. Sequence analysis of the two envelope glycoproteins implicates amino acids 92, 205, 255, 347, 392 and 526 in the HN protein of B95a and HeLa derived viruses as being responsible for phenotypic changes in plaque morphology and antigenicity but do not solely account for host cell tropism.