Lectin Switching During Dengue Virus Infection

Dejnirattisai, Wanwisa; Webb, Andrew I.; Chan, Vera; Jumnainsong, Amonrat; Davidson, Andrew; Mongkolsapaya, Juthathip; Screaton, Gavin

Finally, although DC-produced virus cannot reinfect DCs efficiently, we were interested to determine whether DC-produced virus was still able to infect cells by antibody-dependent enhancement (ADE), which would allow it to replicate by infection of Fc receptor-expressing cells. C6/36-and DC-derived viruses were incubated with increasing levels of pooled convalescent dengue immune serum and subsequently used to infect U937, a monocyte cell line that expresses the Fc receptor and which shows relatively low infectivity without the presence of enhancing antibodies. Viruses produced in both DCs and insect cells were susceptible to enhancement, over the same range of antibody concentrations, showing that DC-produced virus could exploit ADE to replicate in individuals undergoing a secondary dengue infection ( Figure 6A ). In a final series of experiments we investigated whether DC-produced virus could be induced to infect primary human DCs by ADE ( Figure 6B ). DC-produced virus could be enhanced to infection by .20-fold, whereas the already high level of infection of DCs by insectproduced virus was not enhanced further by dengue serum.