The effect of ceruloplasmin on the multiplication and on some biological and physico-chemical characteristics of influenza virus A/PR8/34 (H0N1) cultivated in chorioallantoic membrane fragments. Note 2. Modifications occurring in the course of serial passages.

The results obtained at the first passage of ceruloplasmin-incubated influenza virus A/PR8/34 (H0N1) in chorioallantoic membrane fragments demonstrate the "trap effect" of ceruloplasmin and are characterized by the low values of the ratios between the hemagglutinating and neuraminidase activities and the infectivity of the resulted progens. At the 2nd passage, both in the absence and in the presence of ceruloplasmin the previously observed changes are accompanied by severe modifications in the antigenicity of the progens, as shown by the HAI titres obtained against a rabbit antiserum to influenza virus A/PR8/34 (H0N1).