HIV Might Spread More Quickly Within the Body Than Previously Thought, Monkey Study Indicates
Each rhesus monkey cell infected with the simian immunodeficiency virus, or SIV, produces at least 50,000 viruses over its life span, suggesting HIV spreads more rapidly than previously estimated, according to a study by researchers at Los Alamos National Laboratories, the Santa Fe New Mexican reports.
Researcher Alan Perelson and colleagues created an SIV strain that could infect one cell and reproduce, but the offspring were unable to infect other cells. After infecting rhesus monkeys with the strain, researchers examined the monkeys and counted the number of viruses made from the one cell over its life span.
According to Perelson, SIV and HIV act similarly, so it is likely that HIV could behave the same way. He noted that prior studies, which found that an HIV cell produced 1,000 to 2,000 viruses, examined the cell at a single point in time instead of a cell's entire life span. "Overall, ... this tells us the infection is a lot tougher to combat," Perelson said, adding, "Early in the infection, sharing needles, blood, if a small number of cells are transferred, the disease has a larger chance of spreading through the body quickly."
Bette Korber, a LANL fellow and HIV expert, said the findings are a helpful tool to study HIV, but they cannot be used directly in vaccine research. "This lets us know more what we're up against," Korber said, adding, "Maybe it tells us something about the efficacy of a vaccine. Maybe you can't protect against infection, but you could try to find a way to stop the progression of HIV." According to the researchers, a similar test would be difficult to conduct among humans because the subject would have to be dead before scientists could count how much the virus had reproduced (Vorenberg, Santa Fe New Mexican, 4/13).