Immunofluorescent analysis of murine leukemia virus-infected cells by flow microfluorometry

Flow microfluorometric assay with a Cytofluorograf model 4801 in combination with immunofluorescence was applied to the quantitative assay of cells exogenously infected with mouse leukemia viruses and to the chemical induction of virus in AKR cells. The Cytofluorograf provides sensitivity equal to the visual method and is capable of assaying up to 5000 cells/sec with specificity equivalent to that of the direct visual immunofluorescence assay, thereby providing a large, statistically valid sampling in a fraction of the time required by visual counting. Flow microfluorometry also provides a method of quantitatively resolving fluorescent cell populations on the basis of relative size and degree of fluorescence.