HIV’s ‘hide and seek’ could make it weaker

May 9th, 2009 - 1:54 pm ICT by ANI  

Melbourne, May 9 (ANI): HIV usually plays a game of hide and seek to dodge the immune system, but a new study has claimed that such playfulness actually makes the deadly virus vulnerable at times, according to an Australian study.

The finding could offer insights into the treatment of HIV during the early stages of infection.

At the time of entering a new host, HIV includes a form that researchers call escape mutant.

Although the escape mutant virus is better at evading our immune system, it is weaker and replicates slower than the wild-type form.

“When HIV infects a new host it needs to adapt to this new environment,” ABC News quoted lead author and PhD student Liyen Loh, of the Department of Immunology and Microbiology at The University of Melbourne, as saying.

She added: “The mutations often revert to the original wild-type virus, allowing the virus to regain a fitter state, or the changes may be retained, depending on the individual’s immune system. This explains why some individuals have better clinical outcomes than others.”

In the study, the researchers from the University of Melbourne and the University of Sydney analysed the evolution of the virus using macaque monkeys by infecting them with different quantities of wild-type SIV (the non-human equivalent of HIV) and escape mutant SIV.

They then measured the growth of the virus for the next three months to find out how much time the escape mutant form took to revert back to its fitter wild-type state.

“In the absence of immune pressure the virus will not stay in its weakened state, because it is not beneficial for the virus,” said Loh.

It was discovered that in animals infected with the escape mutant virus, it took 8 days for wild type to appear and it took 8 weeks for them to outnumber the escape mutant form.

The researchers also found that the genetic makeup of the virus affected how fast the virus adapts in the host.

“If (the macaques) get infected with purely one strain of virus it will take longer to adapt to the new host,” said Loh.

In her opinion, the study only focused on one structural part of the virus that mutates, and also claimed that there are many “other bits” that affect how the HIV evolves in an infected individual.

The study has been published in the PLoS journal Pathogens. (ANI)

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