Foamy virus vectors have been used to cure a genetic immune deficiency in dogs, suggests a paper online in Nature Medicine. The results indicate that they may be useful alternative vectors for curing some diseases by gene therapy.
Foamy viruses are a type of integrating retrovirus found in many mammalian species. Unlike other types of retrovirus used for gene therapy, foamy viruses have never been associated with disease in humans.
Dennis Hickstein and colleagues used a foamy virus vector -- a modified form of the virus that acts as a delivery vehicle for a therapeutic gene - to express the gene for the white blood cell integrin ITGB2 in blood stem cells from dogs with canine leukocyte adhesion deficiency. CLAD dogs normally lack this protein and their immune cells consequently fail to migrate to sites of infection. After reinfusion of the corrected stem cells, the dogs showed complete reversal of disease symptoms, lasting more than two years. The authors also looked at where the foamy virus had integrated into the host cell genome, and found that, compared with gammaretroviral vectors, there was a decreased risk of integration near oncogenes
Dennis Hickstein (National Cancer Institute, Bethesda, MD, USA)
Abstract available online.
(C) Nature Medicine press release.
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