Chemical Analysis of the Influenza Viruses a (Pr8 Strain) and B (Lee Strain) and the Swine Influenza Virus

The isolation and purification of particulate components biologically characteristic of influenza virus A (PR8 strain) (l), influenza virus B (Lee strain) (2), and the swine influenza virus (3) have been reported. These components were obtained, by adsorption on and elution from chicken red blood cells combined with ultracentrifugation or by ultracentrifugation alone, from chorioallantoic fluid of chicken embryos infected with the respective types of the influenza virus. By these procedures concentrates of the particles were obtained in preparations of a high degree of homogeneity with respect to particle kind, with characteristic sedimentation constants and average particle sizes, as determined from sedimentation data and from electron micrographs. Preliminary chemical analyses, already reported briefly, showed the three types of influenza virus to be constituted of lipoprotein-carbohydrate complexes containing nucleic acid of the desoxypentose type. The present paper is concerned with a detailed description and comparison of the analyses made on influenza viruses A (PR8 strain) and B (Lee strain) and the swine influenza virus.