Three split-virion vaccines (Vaxigrip, Begrivac, and Influsplit/Fluarix) and three subunit vaccines containing only viral surface glycoproteins (Influvac, Agrippal, and Fluvirin) available for the 1994-95 season were analysed by biological, molecular, and biochemical methods. Although all vaccines are required by health authorities to contain 15 micrograms haemagglutinin per dose of each virus strain, there were significant differences in haemagglutination titres among the examined vaccines of both types. The enzymatic activity of neuraminidase was present in all vaccines except Fluvirin. Total protein content was lower for subunit vaccines. Viral nucleoprotein was detected in all split vaccines but to varying levels according to SDS-PAGE and Western blot analyses. The ovalbumin content was low in general but was about tenfold higher for Influvac than for the other vaccines analysed. This protein may induce hypersensitive reactions among persons with severe egg allergy. All three split-virion vaccines were found to contain the matrix protein; however, it was not detected in the subunit vaccines. Differences in influenza antigen variety in currently available vaccines may affect efficacy, whereas differences in concentrations of nonviral compounds such as ovalbumin and endotoxin may lead to different postvaccination reactogenicity profiles.
Persistent infection with a variant of influenza C/AnnArbor/I/50 virus in MDCK cells has been previously reported. However, the precise molecular mechanism of persistence is still unknown. We show that the release of active progeny virus, as tested for by haemagglutination and acetylesterase profiles, does not take place in freshly seeded MDCK cells. Productive virus replication occurs simultaneously with massive production of structural proteins as shown by immunoprecipitation and immunofluorescence. PCR for the HEF structural proteinencoding segment 4 revealed that positive-sense RNA is present only during virus multiplication whereas negative-sense RNA appears to be constantly detectable, In this study we give initial evidence that influenza C virus can persist in the form of its genomic minus strand RNA, and plus strand transcription, protein synthesis and virus replication remain restricted to productive phases.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.