The binding of dengue type 2 (DEN-2) virus to mammalian (LLC-MK(2) and Vero) and mosquito (C6/36 and AP61) cell surfaces was investigated by a virus-binding assay using purified (3)H-labeled DEN-2 virus. The DEN-2 virus binding to all four cell types was specific and saturable, indicating the presence of a single class of receptors (ranging from 3.7 x 10(3) to 3.5 x 10(4) receptors/cell) with a high affinity for DEN-2 virus (K(d) ranging from 98 to 171 pM). Treatment of cell surfaces with certain glycosidases significantly reduced virus binding to mammalian cell lines, but not to the insect cell lines examined. Furthermore, heparin was found to compete with mammalian cell receptors for binding to DEN-2 virus and to inhibit viral infection of mammalian cells, but heparin had no effect on viral binding to or infection of insect cells. These results confirm previous reports suggesting that DEN-2 virus receptors on mammalian cell lines are different from those on insect cell lines.