Sickly sweet: How HIV uses sugar against us

It’s National Chemistry Week and this year’s theme is the chemistry of candy. What do all candies have in common? Sugar. Lots and lots of sugar.

But when it comes to chemistry, what is sugar — besides delicious?

Sugar is the sweet name we give to strands of carbohydrates built with carbon, hydrogen and oxygen. The sugar we know and love most is sucrose, a carbohydrate strand composed of two simple sugars, glucose and fructose. These simple sugars are energy sources, absorbed directly into the blood stream during digestion — and the main culprits in a sugar high.

But sugars do more than give us a buzz, excess pounds and cavities. Complex sugars, called oligosaccharides, are a vital part of our cellular landscape, coordinating cell-to-cell interactions and stabilizing protein structures. Our immune system uses sugar in signaling structures. Sugars and lipids combine to differentiate blood types.

We are chock full of sugar — making it the perfect camouflage for a deadly virus.

In 2012, 1.6 million people died of AIDS-related illnesses worldwide. There are treatments but still no cure or vaccine for HIV, in part because of the arsenal of weapons the virus deploys to infiltrate and destroy the immune system. Sugar is one of those lethal weapons.

HIV H9 T Cell
HIV H9 T Cell

One particular HIV protein, called gp120, is covered in sugars, allowing it to slip through our immune defenses just like any other harmless protein. Now, Brandeis researchers are turning that sugary weapon against HIV, researching a vaccine that can target gp120.

Some immune systems are better than others at fighting HIV; they have broadly neutralizing antibodies, such as 2G12, which bind to gp120 and block it from being able to infect cells.

Carbohydrate found on gp120

Isaac Krauss, assistant professor of chemistry, and his lab are researching an HIV vaccine that would boost 2G12 antibodies by designing clusters of carbohydrates that closely mimic the sugars on the outside of gp120. By using a technique of directed evolution, Krauss and his team have created several antigenic mimics, meaning they bind well with the 2G12 antibodies. Their next step is to test whether they are immunogenic, meaning if they can elicit an immune response.

If successful, these harmless mimics would spur the production of 2G12 antibodies, which would be able to identify the actual HIV virus and neutralize it.

And that would be very sweet.


Special thanks to graduate student Jenn Bailey, who sweetly contributed to this story. 

Leave a Reply

Your email address will not be published. Required fields are marked *