July 10, 2014
Window of opportunity against HIV comes from 'fitness bottleneck'
By Emory Health Sciences News
New research on HIV transmission shows that viral fitness is an important basis of a “genetic bottleneck” imposed every time a new person is infected. The findings define a window of opportunity for drugs or vaccines to prevent or limit infection.
HIV represents evolution on overdrive. Every infected individual contains a swarm of viruses that exhibit variability in their RNA sequence, and new mutations are constantly appearing. Yet nearly every time someone new is infected, this diverse population of viruses gets squeezed down to just one individual.
The genetic bottleneck effect was known, but now the selection for viral fitness driving it is becoming clear. Researchers have found that viral protein sequences matching a consensus sequence, which is hypothesized to be most fit, are more likely to be transmitted than those that deviate from the consensus.
The results were published Thursday in Science.
“The best explanation for what we are seeing is that frequently, after exposure to HIV, a few cells in the genital tract are infected, without establishment of a systemic infection,“ says senior investigator Eric Hunter, PhD, professor of pathology and laboratory medicine at Emory University School of Medicine, Emory Vaccine Center, and Yerkes National Primate Research Center. Hunter is a Georgia Research Alliance Eminent Scholar and co-director of the Emory Center for AIDS Research.
