Immunostaining of alveolar type II cells from healthy individuals with a monoclonal antibody specific for CFTR (A) and a rabbit antibody against surfactant C (B); C: overlay of A and B. D, E: Confocal microscopy of alveolar type II cells from a healthy individual (D) and a ΔF508 homozygous CF patient. (E) with a monoclonal antibody specific for CFTR. Immunostaining of alveolar type II cells from CF patients (F, G) and healthy individuals (I, J) with a monoclonal antibody specific for ceramide (F, I) and a rabbit antibody against surfactant C (G, J). H: overlay of F, G, K: overlay of I,J. Original magnifications: A-C, F-K: × 200; D, E × 400.