CELL-FUSION ASSAY FOR THE DETECTION OF RUBELLA-VIRUS IN VERO CELLS

Background and objectives: Rubella virus (RV) produces a subtle and sl ow-developing cytopathic effect in Vero cells that is difficult to rec ognize, especially at low multiplicities of infection. In order to fac ilitate the detection of RV in cell culture, we standardized a low-pH virus-mediated cell-fusion assay. Study design: The incubation periods , temperatures, pH and multiplicity of infection were established. The specificity of the method was tested by immunofluorescence assay and cell-fusion inhibition by specific sera. Results: Six days post infect ion, Vero cells were treated for 5 min with fusion medium. After that, monolayers were incubated with medium at neutral pH for 16 h and then stained. Gigantic cells with multiple nuclei were observed. Conclusio ns: The method allowed the observation of unequivocal images that are easier to recognize than the cytopathic effect caused by RV in the sam e cell line. At the same time, the method is simple, accessible and sh own to be specific to demonstrate the replication of several strains a nd isolates of RV in Vero cells. (C) 1998 Elsevier Science B.V. All ri ghts reserved.