The effect of antibodies on endothelial cells during Dengue virus infection (P6138)

Abstract

Abstract Profound vascular leakage in conjunction with elevated viremia is the hallmark of Dengue Hemorrhagic Fever/Dengue Shock Syndrome (DHF/DSS). Antibody (Ab)-dependent enhancement (ADE), in which pre-existing, cross-reactive Ab enhance virus infectivity, is thought to be responsible for increased viremia, while loss of endothelial cell (EC) barrier integrity is the precursor to plasma leakage. However, the relationship between increased viremia and vascular leak has not been established. We hypothesize that DV-Ab immune complexes enhance infection of FcγR-bearing cells causing increased virus production and release of mediators contributing to enhanced EC infection and increased vascular permeability seen in DHF/DSS. Anti-DV human monoclonal Abs (HMAb) were generated by molecular cloning to study ADE. Human dermal microvascular EC (HMEC-1) were infected directly with DV or indirectly using media from K562 cells infected with DV+/-HMAb. HMEC-1 infection and infectious virion production were quantified by qRT-PCR and plaque assay, respectively. HMEC-1 monolayers were assessed by microscopy. Indirect HMEC-1 infection under ADE conditions caused enhancement compared to infection media without Ab, and resulted in aberrant changes in HMEC-1 cell morphology, indicating that under ADE conditions, K562 cells enhance DV infection of ECs by increasing the infectious viral load and potentially releasing soluble mediators that cause EC barrier dysfunction.