Detection of dengue cell-surface antigens by peroxidase-labeled antibodies and immune cytolysis.

The appearance of dengue-specific plasma membrane (DSPM) antigens in infected LLC-MK(2) cell cultures was studied by (51)Cr release in immune cytolysis and at an ultrastructural level using peroxidase-labeled antibodies. DSPM antigen was first detected at 36 h with electron microscopy in approximately 30% of the cells, and this percentage did not increase with time. However, both surface staining with peroxidase-labeled antibodies and (51)Cr release indicated that the amount of DSPM antigen per cell increases with time. The appearance of (51)Cr release in immune cytolysis experiments with dengue-infected cells occurred much later than the peak of infectious virus release. This was in sharp contrast to immune cytolysis with a group A arbovirus, Eastern equine encephalitis, in which the kinetics of release of infectious virus and (51)Cr release were identical. This suggests different mechanisms of insertion of viral plasma membrane antigens in Eastern equine encephalitis and dengue-infected LLC-MK(2) cells.