CFTR and infection: In contrast, F508del CFTR cells had the highest RSV titer on day 2 (4.6 ± 0.2 × 1010 PFU/mL), followed by a decrease in titer on days 4 and 6 post infection (Day 4: 1.1 ± 0.4 × 108 and Day 6: 8.2 ± 1.1 × 107 PFU/mL, respectively, p < 0.007 across all time points).