CFTR and cystic fibrosis: Cftr immunostaining of nasal respiratory epithelium (Figure 4) yielded strong punctuated apical labelling of similar intensity in F30 CF/1-CftrTgH(neoim)Hgu, F29 CF/3-CftrTgH(neoim)Hgu and wild type MF1 and C57BL/6J mice.