[Heterogenicity of influenza A virus NP protein]

Three classes of NP-proteins were detected by 7% polyacrylamide gel electrophoresis of virion proteins of influenza A various strains. Peptide maps of these proteins vary. The pattern of the discrepancies indicates the presence of two types of influenza A virus NP-protein. Incubation during 30 h at 37 degrees C of the preparations of intact viral particles and particles destroyed by nonion detergent NP-40 does not result in changes of the NP, NP2 and NP3 proteins ratio, that is an evidence of their intracellular origin.