Confocal microscopy. Double immuno-staining for pHp and SP-B using a confocal microscope (Red: pHp, Green: SP-B, Blue: Nuclei stained with 4',6-diamidino-2-phenylindole). A-C: AEC II in a HOPE-fixed human lung tissue. A: pHp; B: SP-B; C: overlay of all three channels displaying co-localization of pHp and SP-B in orange color (1000x). D-F: A549 cells treated in the same way as A-C (1000x). Two independent experiments.