EPS8 facilitates uncoating of influenza A virus

Gloria P. Larson; Vy Tran; Shuiqìng Yú; Yíngyún Caì; Christina A. Higgins; Danielle M. Smith; Steven F. Baker; Sheli R. Radoshitzky; Jens H. Kuhn; Andrew Mehle

The permissiveness of each cell line to WSN-GFP was determined and rank-ordered relative to Madin-Darby canine kidney (MDCK) cells, which are frequently used for the propagation of FLUAV (Figures 1A and 1B; Table S1 ). We detected a broad range of susceptibility when infecting cells at a multiplicity of infection (MOI) of 0.2. Relative to MDCK cells, 10 cell lines were highly refractory to WSN-GFP (at least a 10-fold decrease in infection rate) and 12 cell lines were highly permissive (at least a 3-fold increase in infection rate). There was no obvious association between susceptibility, cell type, tumor type, or tissue of origin. MCF7 breast tumor cells were the most refractory with a normalized infection rate of only about 3%, whereas T-47D cells, another breast tumor cell line, were the most susceptible with an infection rate of approximately 1300%. These data were highly reproducible with a strong correlation between results from two independent replicate screens ( Figure S1A ). To ensure that the assay captured the full dynamic range of susceptibility, especially for the highly resistant cell lines, the screen was repeated at an MOI of 2 ( Figure S1B ). Similar infectivity trends were detected at both MOIs, although the upper limit of the assay was reached for multiple cell lines at the higher MOI where effectively all cells were infected ( Figure 1C and S1C). The number of infected cells increased at the higher MOI for most of the resistant cell lines, indicating that these cell lines are not completely refractory to FLUAV infection ( Figure S1D ).