Fig 7. Infectivity and multicycle replication of HK and R5 in HTBE cultures.

(a) The apical sides of HTBE cultures were washed with PBS+ to remove mucins and inoculated with 2x10⁴ FFU of HK (closed circles) and R5 (open circles) with and without addition of mucins using 6 replicate cultures per condition. The inoculum was removed after 1 h. The cultures were incubated for 7 h under ALI conditions, fixed, immuno-stained for viral NP, and numbers of infected cells were counted. (b) The apical sides of washed HTBE cultures were inoculated with 7x10⁴ FFU of the viruses without addition of mucins and processed as described above. Six cultures per virus were fixed 8 h post infection for immuno-staining and counting of infected cells. Viral progeny was periodically harvested by washing the apical sides of the remaining cultures, and the harvests were titrated simultaneously at the end of the experiment. P values were determined using Student’s t-test.