SPN and infection: Infection with IAV consistently led to increased Spn abundance on the apical surface of the HBECs, regardless of IAV strain (A/Puerto Rico/8/1934 [PR8], A/Hong Kong/2/1968 H3N2 [H3N2], or A/California/07/2009 pandemic H1N1 [pH1N1]) (Figure 1A).