N-acetylgalactosamine (GalNAc)-specific lectins mediate enhancement of Hantaan virus infection

Summary. N-acetylgalactosamine (GalNAc)-specific lectins, Dolichos biflorus agglutinin (DBA), and soybean agglutinin (SBA), enhanced Hantaan (HTN) virus infections in Vero E6 and P388D1 cells. Treatment of Vero E6 cells with the lectins either before or during, but not after, virus inoculation resulted in lectin-mediated enhancement of infection (LME), indicating that GalNAc-specific lectin affects an early stage of the infection. Lectin blot and FACS analysis showed that the ability of HTN virus envelope glycoproteins and cell surface molecules to bind DBA and SBA was essential for LME. GalNAc clearly inhibited LME, indicating that the lectins bind with their specific carbohydrate-binding site. These results suggest that a lectin cross-link between the virus and the cell surface is the most plausible mechanism for inducing infection enhancement.