SIV's natural hosts reveal how humans might better manage HIV infection

March 8, 2012

Some monkeys can survive infection by SIV, a relative of HIV, and not develop AIDS. Their immune systems appear to display a pattern of "peaceful coexistence" rather than the all-out conflict provoked by HIV when it infects humans.

SIV's natural hosts are non-human primates found in , including sooty mangabeys and African green monkeys – both species whose infections have been studied in captivity -- as well as other species such as mandrills, drills and suntailed monkeys.

Since SIV's natural hosts have adapted to manage infection rather than fight and lose, we have much to learn from them, a team of scientists from Yerkes National Primate Research Center propose in an article published this week in Science.

Studying how SIV and its natural hosts co-exist could show medical researchers how to improve long-term care for people infected with and reduce mother-to-infant transmission, as well as guide the development of an AIDS vaccine, the researchers write.

The authors include Ann Chahroudi, Steven Bosinger, Thomas Vanderford, Mirko Paiardini and Guido Silvestri. Silvestri is chief of microbiology and immunology at Yerkes and a Georgia Research Alliance Eminent Scholar.

Together with NIH researcher Nichole Klatt, Silvestri is also author of a recent Perspective piece in Science Translational Medicine about the role of CD4+ T cells in HIV infection.

In their review, the scientists call SIV's natural hosts "the door through which HIV came to humans." Genetic analysis has shown that HIV infection of humans arose through multiple cross-species transmissions of SIV from non-human primates.

Distinctive features of SIV natural host infection include a low level of immune activation and a low rate of mother-to-infant transmission, compared to humans. This reflects evolutionary history during the last several thousand years, the authors propose.

"In this view, the genetic features of natural SIV hosts that underlie two key mechanisms of resistance (i.e. low immune activation and target cell restriction) may at least partially reflect evolutionary selection to protect from mother-to-infant transmission," they write.

Researchers have observed that a small number of HIV-infected people exhibit a "natural host-like" phenotype, where low levels of immune activation are seen. In most humans, HIV infection leads to chronic immune activation, which causes health problems even in people who receive long-term antiretroviral treatment.

During infection, SIV's natural hosts also manage to preserve particular types of immune cells including Th17 cells, which help maintain the intestines, and central memory T cells, important for keeping the immune system's ability to respond to previously encountered bacteria or viruses.

Understanding how SIV's natural hosts avoid chronic and preserve immune function could help improve medical care for people living with HIV , the authors conclude.

Explore further: Monkeys resist infection by closing gates that SIV, HIV use to get into cells

Related Stories

Monkeys resist infection by closing gates that SIV, HIV use to get into cells

June 26, 2011
Sooty mangabeys, a type of African monkey, have intrigued scientists for years because they can survive infection by SIV, a relative of HIV, and not succumb to AIDS.

Antibodies help protect monkeys from HIV-like virus, scientists show

May 5, 2011
Using a monkey model of AIDS, scientists have identified a vaccine-generated immune-system response that correlates with protection against infection by the monkey version of HIV, called simian immunodeficiency virus (SIV). ...

Recommended for you

Scientists divulge latest in HIV prevention

July 25, 2017
A far cry from the 1990s "ABC" campaign promoting abstinence and monogamy as HIV protection, scientists reported on new approaches Tuesday allowing people to have all the safe sex they want.

Girl's HIV infection seems under control without AIDS drugs

July 24, 2017
A South African girl born with the AIDS virus has kept her infection suppressed for more than eight years after stopping anti-HIV medicines—more evidence that early treatment can occasionally cause a long remission that, ...

Meds by monthly injection might revolutionize HIV care (Update)

July 24, 2017
Getting a shot of medication to control HIV every month or two instead of having to take pills every day could transform the way the virus is kept at bay.

Candidate AIDS vaccine passes early test

July 24, 2017
The three-decade-old quest for an AIDS vaccine received a shot of hope Monday when developers announced that a prototype triggered the immune system in an early phase of human trials.

Paris spotlight on latest in AIDS science

July 21, 2017
Some 6,000 HIV experts gather in Paris from Sunday to report advances in AIDS science as fading hopes of finding a cure push research into new fields.

Scientists elicit broadly neutralizing antibodies to HIV in calves

July 20, 2017
Scientists supported by the National Institutes of Health have achieved a significant step forward, eliciting broadly neutralizing antibodies (bNAbs) to HIV by immunizing calves. The findings offer insights for HIV vaccine ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.