A549 Cells And Hep-2 Cell Surface Sugar Chain Type Identification, And Its Combination With The H5n1 Avian Influenza Virus Characteristics,

Background The H5N1 virus often leads to acute respiratory disease and death. The pandemic potential of H5N1 virus depends largely on its efficiency of human-to-human transmission. This inefficiency has been speculated to be determined in part by the tropism of influenza virus for the human upper respiratory tract. However, the tropism and pathogenicity of avian influenza A (H5N1) in huamn respiratory tract are poorly understood. Therefore, analysis of the interaction between influenza virus and human respiratory epithelial cells will be critically important to better understand the virus transmission and pathogenicity in humans.Objective To determine H5N1 virus attachment to the human respiratory tract, and to study the tropism of influenza virus, Hep-2 cells and A549 cells derived from human upper and lower respiratory tract were included.Methods Expression of SAa2,3Gal and SAa2,6Gal in A549 cells and Hep-2 cells was examined by using lectin fluorescence and flow cytometry. Binding experiments with FITC-labeled H5N1 virus and indirect immunofluorescence assay were perfomed to study the virus entry into A549 and Hep-2 cells. The entry efficiency was determined by Western blot analysis. Cell viability after H5N1 treatment was measured by MTT assay.Results SAa2,3Gal was prevalent in A549 cells and Hep-2 cells, while SAa2,6 Gal was little found. SAa2,3Gal expression was more regularly observed in Hep-2 cells, rather than A549 cells. The H5N1 virus tested could enter A549 cells and Hep-2 cells. However, viral entry efficiency differed between the two cell lines tested. A549 cells were found to be more susceptible to avian influenza than Hep-2 cells. H5N1-induced cell death was inefficient in A549 cells than Hep-2 cells. Furthermore, the cell death elicited by H5N1 virus was independent of Caspases or PI3K activition.Conclusion The expression of SAa2,3Gal on the cells tested corresponded with the attachment of the H5N1 virus. However, sialic acid only may not sufficient for entry into cells.