High lysosomal activities in cystic fibrosis tracheal gland cells corrected by adenovirus-mediated CFTR gene transfer

Human tracheal gland serous (HTGS) cells are now believed to be a major tar get of cystic fibrosis (CF) gene therapy. To evaluate the efficiency of ade novirus-mediated gene transfer in these cells we tested the adenovirus cons truction containing beta-galactosidase cDNA. We observed that the endogenou s beta-galactosidase activity in cultured CF-HTGS cells was too strong to a llow us to detect any exogenous beta-galactosidase activity. Immunohistolog ical study on sections of human tracheal tissue confirmed the presence of b eta-galactosidase in the serous component of the submucosal glands. We then looked for other lysosomal activities in normal and CF-HTGS cells. We show ed that normal cells already have elevated enzyme values and that CF-HTGS c ells contained 2-4-fold more beta-galactosidase, alpha-fucosidase, alpha-ma nnosidase and beta-glucuronidase activities than normal cells. An analysis of their kinetic constants has shown that this difference could be attribut ed to a lower K-m of CF lysosomal enzymes. More importantly, these differen ces are eliminated after adenovirus-mediated CFTR gene transfer and not aft er beta-galactosidase gene transfer. (C) 1999 Elsevier Science B.V. All rig hts reserved.