A modified immunofluorescence assay for detection of Japanese encephalitis virus-infected cells

Japanese encephalitis virus (JEV) infections are currently detected by indirect immunofluorescence (IF) assay using virus-specific antibodies on acetone-fixed smears. On few occasions, the acetone treatment was reported to damage certain epitopes on JE virus (JEV) glycoprotein. Here, we have made an attempt to adopt quick paraformaldehyde fixation followed by a short detergent treatment of cells in suspension for identification of JEV-infected brain cells of laboratory-reared Toxorhynchitis splendens mosquito larvae using virus-specific antibodies. JEV-positive cells could be scored by the presence of a well defined intracellular immunofluorescence staining against unstained uninfected antibody-treated cells. The advantage of this assay is that stained cell suspensions can be stored for up to 4 weeks, allowing analysis at convenience. Thus, the modified IF assay can be employed as an additional/alternate technique to standard IF assay for detection of JEV in cells and also to screen hybridoma cell lines for anti-JEV antibody production.