Egg-grown and tissue-culture-grown variants of influenza A (H3N2) virus with special attention to their use as antigens in seroepidemiology.
A field strain of influenza A (H3N2) virus isolated in embryonated eggs during the 1984-5 influenza outbreak (A/Finland/13/85E) was compared in an antigenic analysis with virus from the same clinical specimen isolated in MDCK cell cultures (A/Finland/13/85M). The M-virus appeared to be more sensitive to haemagglutination-inhibiting antibodies against heterologous viruses than did the E-virus. The results of propagation and plaque purification experiments support the hypothesis that a single clinical specimen may consist of distinct antigenic variant subpopulations promoted selectively by the host during isolation procedures. Receptor-binding properties are discussed as a possible explanation for this selectivity. A set of 471 paired sera consisting of pre-epidemic and post-epidemic specimens taken from the same subjects in 1984-5 was studied for haemagglutination-inhibiting antibodies to six influenza A (H3N2) virus strains, including the E-virus and the M-virus from A/Finland/13/85. Of the antigens used, the M-virus detected significant antibody increases more frequently than did the E-virus (10.0 v. 5.9%). The superiority of the M-virus may rest primarily in its ability to pick out anamnestic antibody responses. Irrespective of this cross-reactivity, pre-epidemic antibody to the M-virus was fairly well associated with protection. In the set of sera (230 specimens) collected in summer 1985 to represent different age groups, the antibody status against the M-virus was significantly better than the status against the E-virus. The results suggest that, at least in some instances, antibody to MDCK-grown virus is a more accurate indicator of the immune status of a community than antibodies to egg-grown virus variants.
National Public Health Institute, Helsinki, Finland.
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R
Pyhälä
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Pyhälä
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M
Valle
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K
Aho
D000293:Adolescent; D000328:Adult; D000368:Aged; D000956:Antigens, Viral / Q000276:immunology*; D002648:Child; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype; D009980:Influenza A virus / Q000254:growth & development* / Q000276:immunology; D007251:Influenza, Human / Q000276:immunology*; D008875:Middle Aged
D000956:Antigens, Viral