Curses into cures?
One of the problems with gene therapy for inherited lung diseases, such as cystic fibrosis, is effectively delivering the therapeutic genes to diseased tissue. Promising gene therapy vectors, such as lentiviruses, used to shuttle genes simply do not penetrate the wall of the lung effectively when inhaled. Help, however, may be on the way from an unlikely source-deadly viruses, such as Ebola virus and influenza virus, which naturally infect the host through the respiratory system. Exploiting the affinity of these viruses for lung tissue, James Wilson and his colleagues have stripped Ebola and influenza of their lung-binding proteins and then engineered them into the coat of a lentiviral gene therapy vector (Nature Biotechnology, Vol. 19, No. 3, 01 Mar 2001). The resultant vector is much more efficient at delivering genes to lung tissue and holds promise as an agent for the treatment of cystic fibrosis.
To test their system, Wilson and his team studied the efficiency of their hybrid Ebola/lentiviral vector at delivering a test gene-in this instance, a green fluorescent protein that glows green under the microscope-into lung cells in the test tube. They also tested whether the Ebola/lentiviral vector could penetrate the lungs of mice, and also cells lining biopsies of healthy human trachea.
While the hybrid vector appears to be much more effective at gene delivery than other types of vector, it remains to be seen whether vectors containing proteins from deadly pathogens such as Ebola will be appropriate for human use. It is also not clear whether the Ebola/lentiviral vector will be able to penetrate the thick mucus barrier in the lungs of people affected by cystic fibrosis.
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Message posted by: Trevor M. D'Souza