Properties of host components of PR8 influenza virus

The PR8 strain of influenza A virus was grown in canine kidney cell cultures and in chick and duck embryos. After purification by density gradient procedures, the virus preparations were tested for the presence of host antigens with antisera to appropriate host materials. All PR8 preparations were shown to have serologically detectable host components. These host antigens appeared not to be closely associated with the hemagglutinin or neuraminidase spikes, since virus from which essentially all of these structures were removed formed substantial precipitates with antiserum to host material. Evidence is also reported which suggests that cellular actin is an integral component of highly purified PR8 virions, though probably unrelated to host antigen.