New research from scientists at the Los Alamos National Laboratory suggests that HIV replicates at a much faster rate than previously thought.
Previous estimates of a cell at a single point in time suggested that 100 to 200 viruses might be made in each HIV-infected cell, explained Alan Perelson. That figure was later raised to 1,000 to 2,000, he said.
But when studying SIV - the simian version of HIV - in rhesus monkeys, the Los Alamos team found a much faster rate. "When we looked at a cell over its life span, we found each cell was making approximately 50,000 viruses and it looks like that's the minimum," said Perelson.
Given that HIV and SIV act similarly, it is reasonable to believe that HIV could duplicate in the same way, Perelson said.
The SIV strain engineered by researchers could infect one cell and produce offspring, however the offspring were defective and could not infect other cells. This allowed the team to count the virus reproduced from the one cell.
Performing similar tests on humans is difficult since the subjects must be dead before scientists can count how much the virus replicated. Still, the conclusions are similar, said Perelson.
"Overall, though, this tells us the infection is a lot tougher to combat," Perelson noted. "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."
"This lets us know more what we're up against," said Bette Korber, a fellow HIV expert at Los Alamos. "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."
04/14/08
UNITED STATES: Los Alamos Lab Suggests HIV Spreads Faster than Thought
Source: Associated Press; Courtesy of the CDC National Center for HIV, STD, and TB Prevention