title: Cytopathic effects and focus formation by reticuloendotheliosis viruses in a quail fibroblast cell line.
abstract: The T and CS (chick syncytial) strains of reticuloendotheliosis virus (REV) induced focus formation and cytonecrotic changes in a Japanese quail fibroblast cell line designated QT35. The focus was distinctive and readily discernible, consisting of rounded refractile and larger dark-appearing (syncytia) cells usually aggregated along the periphery of a hole within a focus. The foci and cytopathic effects induced by the two strains of REV were morphologically indistinguishable. The focus formation in QT35 cultures was inhibited by chicken antiserum against the homologous or heterologous strain of REV; the homologous antiserum induced a greater inhibition. The altered cells composed of focus exhibited cytoplasmic fluorescence when stained by an indirect fluorescent-antibody technique with either the homologous or heterologous anti-REV serum. When foci that developed in QT35 cultures maintained under fluid medium were enumerated 3 days postinoculation, there were a highly significant correlation (P less than 0.001) and a linear relationship between the number of foci developed and relative virus concentration inoculated, thus justifying the validity of focus assay of REV by this system. The QT35 cell line may provide a useful in vitro system for virological and serological studies of REV.
mesh_terms: D000818:Animals; D002460:Cell Line; D002642:Chick Embryo; D003370:Coturnix; D003588:Cytopathogenic Effect, Viral; D005347:Fibroblasts; D005455:Fluorescent Antibody Technique; D009500:Neutralization Tests; D001356:Reticuloendotheliosis virus / Q000254:growth & development*; D012190:Retroviridae / Q000254:growth & development*; D014779:Virus Replication