[Heterogeneity of an influenza virus population in the manifestation of biological functions (author's transl)].

In a population of influenza virus, virions have different degree of the functional capacities to produce infectious virus, to induce neuraminidase production and to interfere with infectious virus. Fractions of virus were found which had a poor capacity for production of infectious progeny and a relatively high induction of neuraminidase synthesis as well as induction of heterogenous light fractions of RNA in cells. In the population of defective virus a fraction of particles possessing marked interfering activity in the absence of infectivity was found.