Dr. Cristian Apetrei
Writing in the August issue of PLoS Pathogens, a prestigious online journal, Apetrei and colleagues from Tulane University, the University of Pittsburgh, Duke University, Frederick, Inc., and the Los Alamos National Laboratory describe a functional cure of SIV, the simian counterpart of HIV, in rhesus monkeys. A functional cure controls the virus at extremely low levels in the body while a sterilizing cure entirely eliminates the virus from the body. Rhesus monkeys experimentally infected with the virus all displayed very high viral loads -- from 10 million to a billion copies -- accompanied by the loss of CD4+ T cells in blood and tissues, just as occurs in most humans with HIV. But in some of these monkeys, this was followed by complete and durable control of the virus.
Viral loads were undetectable in the blood and tissues of all animals within three months of infection. This continued for the four-year observation period, despite lack of any antiretroviral treatment. Within that four-year interval the monkeys remained healthy, with complete resolution of initial signs of abnormal immune activation. They also seroreverted, meaning their formerly positive SIV antibody tests became negative. The researchers determined this was a functional cure, rather than a sterilizing one, because when immunity was experimentally suppressed, by depletion of the monkeys' CD8+ "killer" T cells, virus growth resumed.
Dr. Laurence is amfAR's senior scientific consultant.
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