Apical infection of neuraminidase-treated human airway epithelia with T3SA+ (a monoreassortant reovirus strain that is isogenic, except for the presence of a single polymorphism in σ1 that renders the virus capable of binding with sialic acid). The apical surfaces of airway epithelia were pretreated with media alone (Control) or with neuraminidase from V. cholerae (VC), Salmonella serotype Typhimurium (ST), or Arthrobactor ureafaciens (AU) to remove sialic acid. After washing, the epithelia were adsorbed apically with T3SA+ at an MOI of 1000 pfu/cell. Epithelia were immunostained at 18 h after infection to detect reovirus proteins, and infected cells were quantified in 10 random fields of view (n = 4). Error bars denote SDs. *, P < .001.