Future studies on immunogenicity in animals that exhibit a high CFTR expression in lungs similar to that in CF (pigs and ferrets) will show whether mucus can stimulate phage adhesion to the lungs, prolong phage therapeutic activity, and how phage particles can overcome immune interference (Barr et al., 2013; Trend et al., 2017). The gene discussed is CFTR; the disease is cystic fibrosis.