Infection-resistant monkeys could be crucial in the fight against HIV

Via Io9, by Alasdair Wilkins.

Sooty mangabeys are a monkey species found on the western coast of central Africa. Their unique immunity to SIV, a relative of HIV, has intrigued medical researchers for decades. Now we know just how their immunity works.

SIV and HIV function in much the same way - the viruses find two molecules on the surface of the cell, which are known as co-receptors. These molecules function much like gates. One of these molecules is CD4, which is found on immune cells known as T cells. The immune response triggered by the appearance of the virus stimulates these T cells, which boost the level of the other co-receptor, CCR5, which in turn facilitates the deadly infection.

But sooty mangabeys are able to avoid that chain of events, thanks to a unique type of T cell called a central memory T cell. When this particular type of T cell responds to the virus, it does so without activating CCR5. This helps the T cells survive the SIV infection, and it's a crucial reason why these monkeys are able to avoid the onset of AIDS. Best of all, central memory T cells are long-lived in the body, and their positioning in the lymph nodes makes them particularly effective in stopping the spread of SIV.

Emory University researcher Mirko Paiardini explains what this means:

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HIV Envelope Discovery Could Reveal New Vaccine Targets

Via hivandhepatitis.com

An international study headed by a UC Davis scientist describes how a component of a potential HIV vaccine opens like a flower, undergoing one of the most dramatic protein rearrangements yet observed in nature.

The finding could reveal new targets for vaccines to prevent HIV infection and AIDS. A paper describing the work was published online this week in the journal Proceedings of the National Academy of Sciences.

In the new study, researchers from the U.S., Sweden and France explored the structure and behavior of the HIV envelope protein complex, which could potentially serve as a component of a vaccine aimed at eliciting the human immune system to generate antibodies against HIV.

"By opening up these less exposed regions, we might be able to raise more broadly cross-reactive antibodies to HIV," said R. Holland Cheng, professor of molecular and cellular biology at UC Davis and senior author of the study.

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[If an item is not written by an IRMA member, it should not be construed that IRMA has taken a position on the article's content, whether in support or in opposition.]

The Mystery of AIDS Immunity: Solved

From TIME Magazine, by Meredith Melnick

Bruce Walker, an AIDS researcher at Harvard University and Massachusetts General Hospital, has long been trying to understand why some people with HIV can remain untreated for decades and never progress to AIDS. On Nov. 4, Walker and colleagues published research that helps explain these HIV controllers: genetic variations that change key proteins in their immune systems.

The genetic variations change about a half-dozen amino acid building blocks; those variants make cells that are infected with HIV visible to the body's immune system and vulnerable to attack. NPR explained:

Five of the six variants are within a protein that controls how certain immune cells, called CD4s, display bits and pieces of viral protein on their outer shell- if they happen to be infected with a virus. HIV has a special affinity for infecting CD4 cells, and without constant antiviral treatment the virus slowly destroys the immune systems of most infected people.

But if a person has the newly discovered amino acid variants, his CD4 cells will be especially good at displaying pieces of HIV in a binding groove, or pocket of their outer coat. That enables killer cells, immune cells called CD8s, to target and kill the infected cells before they can spew forth more viruses.

For most people, the lack of these protective variants renders their HIV-infected cells invisible to their immune system.

Walker's team has also found these variants in people of European and African descent and in Hispanics. His team hopes their findings will help researchers figure out how to manipulate the immune response in people who do not have the benefit of the genetic variations.

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[If an item is not written by an IRMA member, it should not be construed that IRMA has taken a position on the article's content, whether in support or in opposition.]