Saturable attachment sites for polyhedron-derived baculovirus on insect cells and evidence for entry via direct membrane fusion.

摘要: This research provides the first evidence for specific receptor binding of polyhedron-derived baculovirus (PDV) to host cells and lepidopteran brush border membrane vesicles (BBMV) demonstration entry via a nonendocytotic pathway involving direct fusion. The technique fluorescence-activated cell sorting analysis was used investigate specificity between PDV phenotype Lymantria dispar nuclear polyhedrosis virus (LdNPV) membranes. Fluorescein isothiocyanate-labeled found bind in saturable manner gypsy moth line IPLB-LdEIta L. BBMV. possess approximately 10(6) PDV-specific sites per cell. Excess levels unlabeled were highly efficient competing with fluorescein limited sites, further supporting interaction. Major reductions (as high as 70%) after protease treatment indicated that protein is involved. A fluorescence dequenching assay fusion octadecyl rhodamine B (R18)-labeled identify Direct occurred at 27 degrees C both target membranes well 4 55% achieved C. Viral BBMV throughout pH range 11, dramatically increased (threefold) under alkaline conditions normal larval midguts. Treatment chloroquine, lysosomotropic agent, did not significantly affect or infectivity tissue culture assays.