Some Properties of Influenza Virus Filaments shown by Electron Microscopic Particle Counts

Abstract

A strain of influenza virus A which produced abundant filaments was more efficient in agglutinating red cells than non-filamentous strains. The increased efficiency of agglutination was shown by filtration experiments to be due to the filaments. There was no corresponding increase in the efficiency of initiating infection. Treatment of a filamentous preparation with ultrasonic vibrations causes breakdown of the filaments, an increase in agglutination titer but no change in the infectivity titer.