Egg-grown and tissue-culture-grown variants of XXXX with special attention to their use as antigens in seroepidemiology.

@entity778 @entity23338 @entity9258
A field strain of @entity778 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 @entity23338 appeared to be more sensitive to haemagglutination-inhibiting antibodies against heterologous viruses than did the @entity9258 . 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 @entity778 strains, including the @entity9258 and the @entity23338 from A/Finland/13/85. Of the antigens used, the @entity23338 detected significant antibody increases more frequently than did the @entity9258 (10.0 v. 5.9%). The superiority of the @entity23338 may rest primarily in its ability to pick out anamnestic antibody responses. Irrespective of this cross-reactivity, pre-epidemic antibody to the @entity23338 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 @entity23338 was significantly better than the status against the @entity9258 . 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.
