Figure 4

Immunofluorescent staining of the CFTR membrane channel in three heterozygous carriers of the Phe508del-pathogenic variant of the CFTR-gene and three healthy controls demonstrated by similar percentages of spermatozoa with the CFTR protein in the membrane, both in seminal sperm (A) and in spermatozoa after swim-up or density gradient centrifugation (B). Representative images of spermatozoa stained with the fluorescent anti-CFTR antibody and with the Hoechst 33342-dye (C).