An Hypothesis for the Mechanism by Which an Hemagglutinin Inhibitor Affects Vaccinia Virus

A study was made of the loss of hemagglutinin by vaccinia virus under the influence of an hemagglutinin inhibitor originating from a mouse ascites tumor. It was found that the inhibitor reacted with the hemagglutinin by forming a dissociable complex. In examining the possible mechanisms by which stable, hemagglutinin-negative virus is formed, it was noted that the inhibitor exhibited no neutralizing action against hemagglutinin-positive virus, that hemagglutinin negative virus could not be found in cloned populations of hemagglutinin-positive virus, and that there was no obvious growth advantage shown by the hemagglutinin-negative virus in the presence of inhibitor. For these and other reasons the hypothesis is presented that the inhibitor facilitates the emergence of stable, hemagglutinin-negative virus by complexing with and gradually eliminating the hemagglutinin, which might be necesary as a template for the formation of more hemagglutinin.