engleski

Altering Diversity Of Mumps Virus Populations

Background Mumps virus belongs to RNA family of viruses. It causes respiratory infection that is usually characterized with parotid gland swelling. Encephalitis or meningitis occurs in 1 - 10% of mumps cases due to highly neurotropic nature of this virus. Vaccines currently in use pose two distinct issues - some of them are not sufficiently attenuated while others are overly weakened or do not protect against currently circulating strains. Rational design of vaccines presents ways to develop them in more efficient manner. Altering viral population diversity, a main reason of severe virulence of RNA viruses, has been described as a rational approach to design attenuated RNA viruses. ObjectivesThe aim of this study was to isolate a variant containing polymerase of changed fidelity (lower or higher) from mumps virus population by passaging virus in vitro in the presence of mutagen. This was expected to result in increased or decreased population diversity and potentially attenuated phenotype. Methods A wild-type mumps virus was passaged over the course of 21 passages in A549 cells in the presence or absence of ribavirin. Concentration of ribavirin that does not effect cell viability or proliferation was chosen based on MTT assay. RNA was isolated from cell culture supernatants of control and ribavirin-treated samples from 6 different passages as well as from parental virus. It was used for amplification and preparation of library for next-generation sequencing (NGS) which was performed on Illumina Miniseq platform. Results Analysis of the sequencing data showed accumulation of ribavirin specific mutations in treated viruses. Diversity in ribavirin treated viral populations was approximately 2 - 4 fold higher than in control or parental virus depending on passage. Despite this high rate of mutations, virus was still able to replicate to high levels in the presence of ribavirin. We hypothesize that obtained viral population is resistant to ribavirin treatment which points to very high adaptive capability of mumps virus population. Our next step is to determine if there is a specific viral variant present in this population that is resistant to ribavirin and what are biological characteristics of obtained viral population. The findings of this study emphasize the importance of interaction of different viral variants in the same population as well as observing viral population as a single evolution unit.

mumps, vaccine potential, viral population

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