CXADR and infection: Epithelia expressing hCAREx8 showed approximately 5-fold greater gene transfer than epithelia expressing GFP (Figure 2N) or mock transduced (Figure S3) and close to a 100% increase in gene transfer compared to epithelia expressing hCAREx7 (Figure 2N) This increase in infection is similar to previously published results for glycophosphatidylinositol-linked hCAR which is missing the transmembrane and cytoplasmic domains and localizes explicitly to the apical surface of polarized airway epithelia [27].