Incomplete Forms of Influenza Virus

Abstract

Publisher Summary This chapter describes the experimental conditions required for the production of fully active and incomplete influenza virus. Well-adapted laboratory strains of fully active virus are grown from dilute seeds and harvested when the virus activity becomes maximal. The formation of large amounts of incomplete influenza virus has been observed in embryonated eggs and in a number of other host-cell systems. Incomplete influenza virus is produced also in tissue cultures seeded with large concentrations of Standard virus. Incomplete virus particles are practically undistinguishable from the fully active virus in size, shape, and biologic surface characteristics. They differ from the fully active particles by having a lower sedimentation constant, by the apparent lack of infectivity, and by their capacity to interfere with and inhibit the propagation of the infective virus. The chapter also discusses the various hypotheses about the mechanism responsible for the formation of incomplete virus, along with the nature and origin of the virus.