To address if the expression of ST14 or TMPRSS11D on cells is sufficient to trigger infection-induced fibrin clotting, we transfected non-clotting ACE2-293T cells with plasmids encoding full-length ST14 or TMPRSS11D genes, then infected the transfected cells with a delta variant of pSARS-2 for fibrin clotting assays. Here, ACE2 is linked to infection.