September 29, 2010
A Possible Vaccination for HIV?
(Ivanhoe Newswire) "“ There are 31.1 million adults and 2.1 million children living with HIV in the world. There is no cure for the disease. But what if there was a vaccine that could be administered to everyone to stop the spread of HIV? The HIV/AIDS epidemic would be over.
One way to produce an HIV vaccination is to teach the immune system to recognize certain protein structures on the surface of the HIV virus and produce antibodies that will bind to the structures and neutralize HIV. To do this, scientists must identify a certain viral structure, cut it off, and then find some way to present them to the immune system. However, when some parts of the surface of HIV is remove antibodies don't recognize it or bind to them. A research team at the National Institute of Allergy and Infectious Diseases (NIAID) has developed a way to avoid this problem.
The team has found a way to extract a portion of the surface of HIV that is recognizable to the antibody, known as an epitope, into a computer designed protein scaffold. The scaffold locks the epitope shape recognized by the immune system. The scientists believe that when this epitope is injected into an animal, and eventually a human, it will be recognized by the immune system. The immune system will make antibodies against it. These antibodies could serves as an army ready to attack the virus from invading the body.
To demonstrate this scaffolding technique, the scientists applied it to a shape-changing epitope on the surface of HIV that is recognized by an HIV-neutralizing antibody known as 2F5. The epitope is a helical or spiral shape when removed from the surface of HIV, but the 2F5 antibody-recognizable version of this epitope has an irregular, kinked shape. The scientists placed copies of the kinked epitope into scaffolds that locked it in that form. Then the researchers injected these scaffold-bound epitopes into guinea pigs. The animals' immune systems made antibodies very similar to 2F5 that bound tightly to the epitope.
This study demonstrates that the making of protein scaffolds can be a potentially useful approach in vaccine design. The NIAID researchers are continuing to refine this technique and apply it to the design of vaccines for HIV/AIDS as well as other infectious diseases.
SOURCE: Proceedings of the National Academy of Sciences, published online September 28, 2010