Infectious Cell Entry Mechanism of Influenza Virus

摘要: Interaction between influenza virus WSN strain and MDCK cells was studied by using spin-labeled phospholipids electron microscopy. Envelope fusion negligibly small at neutral pH but greatly activated in acidic media a narrow range around 5.0. The half-time less than 1 min 37 degrees C Virus binding almost independent of the pH. Endocytosis occurred with about 7 pH, 50% initially bound internalized after h. Electron micrographs showed particles coated pits microvillous surface plasma membrane endocytosis into vesicles. Chloroquine inhibited replication. inhibition when drug added not later 10 inoculation. caused an increase lysosomal 4.9 to 6.1. did affect binding, endocytosis, or envelope many remaining trapped inside vacuoles even 30 presence drug, contrast only few secondary lysosomes its absence. replication artificial condition, i.e., brief exposure inoculum medium followed incubation chloroquine, also observed. These results are discussed provide strong support for infection mechanism proposed previously: uptake endocytosed vesicles lysosome, surrounding vesicle lysosome because low This allows viral genome enter target cell cytoplasm.