Several problems confounded these experiments and the gene therapy studies using adenoviruses for cystic fibrosis. Unlike retroviruses, the effect of adenoviruses in these studies was fleeting because these vectors did not insert into a host cell's genetic material. Moreover, adenoviruses apparently provoked an immune reaction against them, thus compromising their utility. According to Dr. Pitt, fetal lung gene transfer is particularly promising. Furthermore, retroviruses are more likely to infect progenitor cells in the fetal lung than in the mature lung.
Progenitor cells have the potential to give rise to a larger number of cells that line the airways.
The research team is currently studying the transfer of therapeutic genes, including the gene to correct the defective cystic fibrosis protein, into sheep fetal lungs. In other experiments, they also are modifying the retrovirus to enhance its efficacy as a vector. For more information, please see Genetics and Gene Therapy Archives . UPMC Health System News Bureau pages have been accessed times since June 1, 2000.