Accumulation of defective interfering viral particles in only a few passages in Vero cells attenuates mumps virus neurovirulence.

Immunization programs have implemented live attenuated mumps vaccines which reduced mumps incidence ≥97%. Some of the vaccine strains were abandoned due to unwanted side effects and the genetic marker of attenuation has not been identified so far. Our hypothesis was that non-infectious viral particles, in particular defective interfering particles (DIPs), contribute to neuroattenuation.

Induction of IFN-α subtypes and their antiviral activity in mumps virus infection.

Human type I interferons (IFNs) comprise one IFN-β, -ω, -κ, and -ɛ and 12 different IFN-α subtypes, which play an important role in early host antiviral response. Despite their high structural homology and signaling through the same receptor, IFN-α subtypes exhibit different antiviral, antiproliferative, and immunomodulatory activities. Differences in the production of IFN-α subtypes therefore determine the quality of an antiviral response.

Critical factors for the replication of mumps virus in primary chicken embryo fibroblasts defined by the use of design of experiments (DoE).

Live attenuated vaccines against mumps virus (MuV) have been traditionally produced by passaging the virus in the embryonated chicken eggs or primary chicken embryo fibroblasts (CEFs). Virus propagation on these cell substrates enables successful virus attenuation and retains it sufficiently antigenic to induce lasting protective immunity in humans. The aim of this study was to identify critical factors for MuV replication in primary CEFs grown on a small-scale level in order to explore possibilities for improvements in the virus replication and yield.

Concentration and purification of rubella virus using monolithic chromatographic support.

The production of economically acceptable viral vaccines of high quality requires simple and efficient methods for purification and concentration of viral particles. Ion-exchange chromatography (IEC) has become one of commonly used methods for large-scale downstream purification of viruses. Viruses possess different biological and/or biochemical properties and therefore IEC conditions must be established specifically for each virus.

Comparisons of mumps virus potency estimates obtained by 50% cell culture infective dose assay and plaque assay.

The two most commonly used methods for the determination of a virus potency are plaque assay and 50% cell culture infective dose (CCID(50)) assay, both based on cytopathic effect observation. We compared the potency estimates obtained by plaque and CCID(50) assays for nine mumps virus strains that produce different cytopathic effects in Vero cells. The ratios of CCID(50) and plaque assay quantification results differed for different strains and were in a range of 0.