Crucial role of the N-glycans on the viral E-envelope glycoprotein in DC-SIGN-mediated dengue virus infection

We generated in the mosquito cell line C6/36 a dengue virus (DENV) resistant to Hippeastrum hybrid agglutinin (HHA), a carbohydrate-binding agent (CBA). The genotype and phenotype were characterized of the HHA resistant (HHAres) DENV compared to the wild-type (WT) DENV. Sequencing the structural proteins of HHAres resulted in two mutations, N67D and T155I, indicating a deletion of both N-glycosylation sites on the viral envelope E-glycoprotein. The HHAres DENV could replicate in mammalian and mosquito cells that are lacking dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) expression. In contrast, DC-SIGN expressing human cells namely monocyte-derived dendritic cells as well as DC-SIGN-transfected cells were no longer susceptible to HHAres DENV. This demonstrates a crucial role of the N-glycans in the E-glycoprotein in the infection of dendritic cells, which constitute primary target cells of DENV during viral pathogenesis in the human body.

► First time generation of a dengue virus resistant to a carbohydrate-binding agent. ► This mutant dengue virus deleted both N-glycans on the viral E-glycoprotein. ► The mutant virus cannot infect its main target cell, the DC-SIGN+ dendritic cell. ► The mutant virus could replicate in (DC-SIGN−) mammalian and insect cell lines. ► The viral N-glycans are crucial for DC-SIGN receptor interaction and infection.