Abstract
By the hemagglutinaton-inhibition tests with human convalecent sera it was found that both P and Q phase viruses were found in strains of Asian influenza virus.
These viruses appeared to be similar to one another antigenically but differed in their avidity for antibody.
In the course of these studies four main differences were found between P and Q strains; avidity, for antibody, sensitivity to nonspecific inhibitors, heat resistance of hemagglutionin, and agglutinability of cow red cells.
Q strain of Asian virus were not sensitive to the unstrapped 2-inhibitor and showed heat resistance of hemagglutinin. P strains of Asian virus and all strains of influenza A including swine influenza failed to show the agglutination of cow cells, but Q viruses agglutinated cow cells. The agglutination produced by Q viruses was similar to that of Lee strain of influenza B. After intranasal passages of Q virus in mice or treatment with periodate, a change of Q to P phase could be demonstrated.
The P variant induced in such a way reacted to efficient titer with human convalecent sera and with non-specific inhibitors, and lacked the heat resistance and agglutinabilty of cow cells.
These data suggested that reactive group of Q strain was subsurface in virus particle.
