Flow Cytometric Determination for Dengue Virus-Infected Cells: Its Application for Antibody-Dependent Enhancement Study

The theory of antibody-dependent enhancement plays an important role in the dengue virus infection. However, its molecular mechanism is not clearly studied partially due to lack of a sensitive assay to determine the dengue virus-infected cells. We developed a flow cytometric assay with anti-dengue antibody intracellular staining on dengue virus-infected cells. Both anti-E and anti-prM Abs could enhance the dengue virus infection. The anti-prM Ab not only enhanced the dengue virus infected cell mass, but also increased the dengue virus protein synthesis within the cells. The effect of anti-prM Abmediated enhancement on dengue virus infection is serotype-independent. We concluded that the target cell-based flow cytometry with anti-dengue antibody intracellular staining on dengue virusinfected cells is a sensitive assay to detect the dengue virus infected cells and to evaluate the effect of enhancing antibody on dengue virus infection on cell lines or human primary monocytes.