Fixation of "neutralized" influenza virus by susceptible cells.

It is well known that specific antibody, under appropriate conditions, will prevent viral infections, but thorough knowledge concerning how this is accomplished is incomplete. Andrewes (1929) after working with virus III in tissue cultures suggested the possibility that immune serum acts by preventing the virus from entering the cells; if the serum fails to do this, invasion of cells occurs. Sabin (1935) working with vaccinia, pseudorabies, and herpes viruses concluded that a union does not take place between these viruses and the protective substance in antiviral sera. He believed that if a virus was fixed first to the susceptible cell, infection took place, whereas if the protective substance was fixed first or simultaneously with the virus, infection did not occur. Adsorption studies have furnished convincing evidence that influenza virus forms a sufficiently strong union with the antibody and that the antibody along with the virus is removed by centrifugation (Smorodintseff et al., 1936; Burnet, 1937; Smith and Andrewes, 1938; Friedewald, 1944). The influenza virus-antibody complex would seem to be a satisfactory one to use in determining whether or not this neutralized virus could make contact with the susceptible cell. Neutralized virus is not always easy to detect, but the reactivation method of McKee and Hale (1948), using homologous concentrated inactive virus, seemed to be applicable to this particular problem. Although a number of different cells are known to fix influenza virus, those lining the allantoic sac of the embryonated chicken egg were chosen for the initial investigation. This study was undertaken to determine whether neutralized influenza virus is fixed to these susceptible cells.