[Interrelationships between the interfering capacity of an "incomplete" virus and its infectivity].

A comparative analysis of UV inactivation curves of the interfering activity of "incomplete" influenza virus and infectivity showed certain differences in the structures responsible for these functions. All the data exclude the role of virus protein and virus-induced interferon of "incomplete" influenza virus and suggest that RNA is responsible for this interference. The size of the "target" of the "incomplete" virus interfering capacity calculated on the basis of sensitivity to UV-light is approximately 40 times as small as that of the "target" responsible for infectivity. The analogous pattern of UV inactivation in the standard influenza virus and the so-called Magnus virus suggests that in the latter the infectivity is due to the presence of complete virions in the preparation.