Quantitative Assays for Virus Detection

The indirect immunofluorescence assay (IFA) is a useful means of determining the number of cells productively infected with virus [1-2]. This assay is inexpensive, quantitative, and can be done using fixed cells (Fixed Cell Immunofluorescence) or live cells (Live Cell Immunofluorescence). Use of the fixed cell assay has the advantage of safety in that the virus is inactivated by the fixing procedure. The live cell assay is useful when working with labile antigens that might be stripped off the cells during fixation. We have relied on the fixed cell IFA (Fixed Cell Immunofluorescence) as a means of confirming anti-HIV efficacy of candidate compounds.