BPIFB1 and cystic fibrosis: Therefore, we investigated whether BPIFA1 and BPIFB1 could inhibit growth of the classic CF bacterial pathogen, P. aeruginosa. We found that recombinant BPIFA1 and BPIFB1 proteins do not inhibit growth P. aeruginosa (PAO1 strain), as measured by optical density or CFU counts.