As a health science student at Boston University, I am always excited when the lectures in my classes relate to the topics I hear about in the BLC. Lately, I was assigned to read an article dealing with new progress made in developing a possible vaccine for HIV. Researchers at Oxford University have recently discovered aspects of the virus’ protective structure that may actually make it vulnerable.
At its most basic level, HIV is a bundle of proteins and carbohydrates. While most attempts at vaccine development have been focusing on the proteins, this method has so far been unsuccessful. HIV always seems to be one step ahead of the body’s immune system, mutating and shifting its proteins so that developing an effective antibody is extremely difficult. However, Dunlop et. al. have made some interesting discoveries by taking a closer look at the carbohydrate portion of the structure.
“Most of the antigenic surface of HIV is covered by carbohydrates,” says Dr. Christopher Scanlan, one of the researchers involved in the project. “It’s often called the glycan shield. The virus needs to be continually evading the immune system, and this shield is perhaps the most effective strategy.”
This “glycan shield” acts as a sort of cloaking device as the virus makes its way through the body, hiding it from the immune system. Normally, it is one of HIV’s primary means of protecting itself, but the scientists think they may have discovered a flaw in this armor that they might be able to turn against the virus. The structure is unique in that the surface carbohydrates are packed so closely together, and while this makes the defense mechanism effective, it also prevents the typical modification that would normally occur in other viruses. In other words, the researchers have found a stable portion of HIV for the body’s immune system to recognize and latch onto. Furthermore, they discovered that certain carbohydrates that coat the outside of yeast cells are remarkably similar to the stable carbohydrates on the outside of HIV. If the researchers can modify the yeast carbohydrates to look more like the ones on HIV, they may be able to create a safe and effective vaccine.
Though it may just be because I am a biology nerd, I love it when I can learn about all the mechanics of the human body and how it interacts with the diseases to which it is exposed. It’s even better when I can learn about something like this, which may be a step in the right direction for finally developing a tool to fight this dangerous and adaptive virus.
“Polysaccharide mimicry of the epitope of the broadly neutralizing anti-HIV antibody, 2G12, induces enhanced antibody responses to self oligomannose glycans.” Dunlop, D.C. et. al. Glycobiology 2010.
The BLC would like to thank Rachel Corrado for her contribution to our blog and her continued service to the HIV community.