The sensitivity of cystic fibrosis cells to diphtheria toxin

Cystic fibrosis (CF) cells have been reported to have a defective acidification and it has been suggested that they may be less sensitive than normal cells to diphtheria toxin (DT). A comparative analysis of DT toxicity in CF and normal cells, both in terms of kinetics of cell intoxication and of cell survival, shows very little difference, which makes it unlikely that diphtheria epidemics contribute to accounting for the large diffusion of the CF trait. DT penetrates cells from endosomal compartments different from those defective in CF cells.