Dengue Fever Research Today is a free monthly online journal that collates and summarizes the latest research about Dengue Fever, including details on symptoms, risk factors, diagnosis, treatment, prevention.

Flow cytometry-based assay for titrating dengue virus.

Lambeth CR, White LJ, Johnston RE, de Silva AM

Department of Microbiology and Immunology, CB #7290, University of North Carolina, Chapel Hill, NC 27599, USA.

Plaque assays for titrating dengue virus (DENV) are time-consuming and not suitable for strains that do not plaque. Fluorescence-activated cell sorting (FACS) has been used to detect DENV-infected cells. Here we describe a FACS-based assay for titrating DENV. We determined that at 24 h postinfection, the number of infected cells detected by FACS represented the first round of infection and therefore could be used as a readout of the number of infectious particles in the inoculum. When the titers of different laboratory and clinical strains of DENV were compared using FACS, plaque, and endpoint dilution assays, for most strains the FACS titers were comparable to titers obtained by plaque or endpoint dilution assays. The FACS assay is an improvement over the plaque assay because the infection period is reduced from 5 to 7 days to 24 h and the assay can be used to titrate clinical isolates that frequently do not form clear plaques on cell monolayers. The novel FACS-based methods described here will facilitate laboratory studies of dengue.

Published 7 July 2005 in J Clin Microbiol, 43(7): 3267-72.
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