Induction of interferon in human leukocyte cultures by natural pathogenic respiratory viruses

Some common viruses responsible for respiratory disease have been reported to be poor inducers of interferon (IFN). Therefore, we have studied the induction of IFN in cultures of human leukocytes exposed under standardized conditions to various concentrations of adenovirus type 7A, coronavirus 229E, an influenza type A virus (H3N2), a rhinovirus, and respiratory syncytial virus (RSV). All five viruses induced substantial amounts of IFN at a multiplicity of infection of one infectious unit per cell or less. Leukocyte cultures from 50 healthy children were exposed to a standard concentration of each of the viruses. IFN was induced almost without an exception, but the amounts produced varied extensively according to both the virus and the individual leukocyte donor.