CFTR and cystic fibrosis: Cysteamine is effective in either rescuing and stabilizing misfolded F508del-CFTR mutant at the PM.9, 10 Notably, cysteamine reduces lung inflammation in vivo through re-establishing CFTR function either in CftrF508del/F508del mice or in CF patients bearing class II CFTR mutations.9, 10, 33, 34 To determine whether the effects of cysteamine on bacterial killing are secondary to its ability to rescue CFTR function, BMDMs were isolated from mice in which the gene coding for CFTR has been knocked out by homologous recombination (i.e., Cftr−/− mice).