Demonstration of interference between dengue virus types in cultured mosquito cells using monoclonal antibody probes.

Cultured Aedes albopictus cells (clone C6/36), persistently infected (PI) with dengue virus type 1 (dengue-1) were found resistant to superinfection with dengue virus type 3 (dengue-3). This was determined by indirect immunofluorescent (IF) staining of cultures using monoclonal antibody against a dengue-3 type-specific antigen. Dengue-1 PI cultures stained with this antibody 3 days after superinfection with dengue-3 virus (m.o.i of 2) had dengue-3 antigen in 0.1 to 1.0% of the cells. Control cultures infected with dengue-3 at the same multiplicity contained dengue-3 antigen in greater than 90% of the cells. The resistance to superinfection was not interferon-mediated, and occurred within 20 h after primary infection. In cultures simultaneously infected with two dengue virus types, one virus type was excluded from replication in most cells. A small population of cells was also found (about 1%) that contained type-specific antigen of both dengue virus types.