Figure 7.

Proportion of the propagation-competent virus particles in virus stocks. Monocyte-derived macrophages (Mɸs) were grown on glass coverslips, infected with A/Beijing/353/89 (H3N2), A/Vietnam/1194/2004 (H5N1), or A/Anhui/1/2013 (H7N9) influenza viruses at multiplicity of infection (MOI) of 0.01. After 1 h incubation, cells were washed and overlaid with 1.2% Avicel in E-MEM with added trypsin. After 15 h incubation, cells were fixed, permeabilized, and stained for viral protein expression. (A) Productive and abortive infection events were calculated. The results represent the mean values + SDs of the means from the cells of four different donors. From each donor, four coverslips with 80 to 500 infection events were counted. The statistical significance of differences between H5N1 and H3N2 or H7N9 was determined by Student’s t-test, *<0.05. (B) Representative immunofluorescence images of infection events for each virus. Infection events were considered productive if three or more adjacent cells were infected. If two or less adjacent cells were infected, the infection event was considered abortive. Immunofluorescence images from one representative donor are shown.