Finally, to determine if the influenza virus-MUC1 interaction occurs during infection in the context of the native HAE microenvironment, we inoculated HAE cultures with >5 × 105 PFU (approximate multiplicity of infection [MOI] of 10) of A/Udorn/307/72 and subsequently chilled the cultures to 4°C so as to irreversibly stabilize virus adsorption and restrict cellular entry (34). This evidence concerns the gene MUC1 and infection.