MUC1 and infection: To determine the impact of membrane-anchored mucins on infection of diverse SARS-CoV-2 clinical isolates, we infected our MUC1 and MUC4 GOF Calu-3 lines with alpha (B.1.1.7), beta (B.1.351), gamma (P.1), epsilon (B.1.429) and WA/1 variants.