Co-localisation by immunofluorescence of CFTR and actin. (A) The pattern of CFTR (green staining) and actin (red staining) stainings was essentially apical in control cells as well as in cells treated with Sal/FP (B). (C) The incubation of cells with S. aureus supernatant induced alteration of the localisation of CFTR that appeared to be cytoplasmic, in parallel with a disorganization of the actin network. (D) Treatment of S. aureus supernatant pre-incubated cells with Sal/FP restored CFTR and actin apical stainings. (E) Quantification of the co-localisation of CFTR and actin showed that 2% S. aureus supernatant decreased the co-localisation index compared to the index in control cells, but the difference was not significant; the treatment with Sal/FP alone or after S. aureus supernatant incubation significantly enhanced the co-localisation of the 2 proteins compared with control or with S. aureus supernatant-treated cells (*, p < 0.05). Data represent the mean ± SEM of 3 different experiments.