title: Infectivity of human coronavirus strain 229E.
abstract: The replication of human coronavirus strain 229E was observed by using indirect immunofluorescence in infected monolayers of MRC continuous cells. By 8 h after infection, bright cytoplasmic fluorescence was detected in cells infected with human coronavirus 229E. Discrete foci of infection were observed from 8 to 16 h after infection in cells infected with high dilutions of human coronavirus 229E; each fluorescent focus corresponded to a single virus infection. A fluorescent focus assay is described, using indirect immunofluorescence, which is more sensitive than the established techniques of tube titration and plaque assay. Particle/infectivity ratios for unpurified and purified virus preparations revealed a considerable drop in infectivity on purification.
mesh_terms: D002460:Cell Line; D003332:Coronaviridae / Q000254:growth & development* / Q000302:isolation & purification; D003588:Cytopathogenic Effect, Viral; D005347:Fibroblasts; D005455:Fluorescent Antibody Technique; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010948:Viral Plaque Assay; D014779:Virus Replication