In a related paper in the July 1998 issue of Nature Medicine, Dr. Walker and NIAID colleagues report that genetically marked but unaltered CD4+ T-cells, infused into six HIV-infected twins, persisted in the blood for an extended period of time (4 to 18 weeks) after transfer.
"This was an unexpected finding," Dr. Walker says. "Transferred cells were assumed to be short-lived. The fact that they live for weeks to months provides a rational basis for transfusing genetically altered cells to fight HIV infection."
To trace the infused cells, Dr. Walker and colleagues injected them with a marker gene called neomycin phosphotransferase. They used this gene because it has a track record for safety, having been used in many cancer and other clinical trials.
Their results also showed that in the HIV-infected twins, new supplies of CD4+ T-cells were coming mainly from division of mature T-cells rather than from stem cells, the precursors of all immune system cells. Thus, once T-cells with certain specificities are lost to HIV infection, they may be difficult to replace.
According to Dr. Walker, this finding suggests that "adoptive transfer of T-cells may prove to be a feasible approach to combating the virus."
NIAID is a component of the National Institutes of Health (NIH). NIAID conducts and supports research to prevent, diagnose and treat illnesses such as HIV disease and other sexually transmitted diseases, tuberculosis, malaria, asthma and allergies. NIH is an agency of the U.S. Department of Health and Human Services.
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Contact: June Wyman
jwyman@nih.gov
(301) 402-1663
NIH/National Institute of Allergy and Infectious Diseases
1-Jul-1998