Radioimmunofluorescent antibody technique for detection of reovirus antigen in cell culture.

Antibody against reovirus type I must partially purified and conjugated with fluorescein isothiocyanate (FITC). The FITC-labeled antibody was then conjugated with 125I. A gamma globulin fraction of normal sera was similarly labeled with FITC followed by a 131I label. The FITC + 125I-labeled immune reagent was then mixed on an equal protein basis with the FITC + 131I control reagent. This mixture was used to stain acetone-fixed reovirus-infected cover slips. After staining, the cover slips were examined by fluorescence microscopy. Infected cover slips demonstrated characteristic reovirus immunofluorescence, whereas uninfected cover slips were negative. After visual examination, the cover slips were placed in tubes and counted in a two-channel gamma analyzer. By comparing the quantitative isotope data with the qualtitative information from immunofluorescence on a single preparation, it was possible to correlate antigen production sites with quantitative production values.