(A) HAE cells were infected with 200 PFU of CI-1 HPIV3 EGFP containing SC9779 HN/F, SC9779 HN T193A-H552Q/F, or HN H552Q/F at the apical surface. Viruses were collected from the apical surface of the HAE cells on days 1, 2, 3, 5, and 7 after initial infection. (B) Titration of HPIV-3 CI-1 EGFP viruses (WT CI-1 or HN mutants) of virus collected from HAE cells 1, 2, 3, 5, and 7 days after initial infection (PFU/mL). Results depict a representative experiment from 3 biological replicates; data shown as mean ± SEM.