HIV devastates the body's immune system by taking over and killing a particular class of white blood cells known as CD4+ helper T cells. These cells coordinate the body's defense against foreign invaders. Without the normal array of T cells, HIV patients have weakened immune systems, leaving them susceptible to infections.
Stanford researchers have now found that low doses of the drug called motexafin gadolinium (or Gd-Tex) selectively kills HIV-infected T cells. "Gd-Tex worked in vitro," said Leonard Herzenberg, PhD, professor emeritus of genetics and senior author of the study reported in the Feb. 18 issue of the Proceedings of the National Academy of Sciences. "It selectively killed the HIV-infected cells when they were in a mixture with healthy white blood cells. And to our surprise, only the infected CD4+ T cells were killed."
Gd-Tex is now being tested in humans as a cancer treatment. The drug acts by accumulating in tumor cells and attacking the molecules that normally protect the cells from one type of stress. The cells therefore die more readily during radiation treatment.
When Herzenberg and his wife, Leonore Herzenberg, PhD, professor of genetics, learned about Gd-Tex, they had a hunch that the drug might also be effective in controlling HIV. Earlier studies had shown that the HIV virus attacks the cell's natural defenses against harmful molecules by reducing levels of a protective molecule called glutathione. When glutathione drops below a certain level, the weakened cell gives in to the stress an
Contact: Amy Adams
Stanford University Medical Center