Because HIV mutates very rapidly, developing an HIV vaccine that produces neutralizing (protective) antibodies is challenging. By examining the structure and function of neutralizing antibodies that are found in individuals after natural infection, researchers believe they will be able to design more effective vaccines against the virus.
However, such broadly neutralizing antibodies are hard to find and isolate from patients. They are rarely found in the early days after infection and have only been found in a small number of long-term infected individuals. Few have been well characterized.
NIAID-funded researchers recently developed innovative methods to more readily isolate broadly neutralizing antibodies from HIV-infected patients. They analyzed more than 500 individual antibodies and found that most of them prevented HIV infection in the test tube by binding to a conserved region on the virus that interacts with the CD4 protein on the surface of T cells, an essential first step in infection. Several of these antibodies more potently inhibited and more broadly reacted with different HIV strains than previously described antibodies.
The researchers further analyzed the most potent HIV antibody using methods that identified the interaction between the antibody and the virus at the level of individual atoms. The results showed that the antibody-virus binding event is similar to that described by others for different HIV antibodies and suggests mechanisms by which these antibodies can prevent infection.
Examining this large number of new HIV antibodies will help guide the development of an HIV vaccine, as they will serve as models for the types of protective antibodies that novel vaccine candidates should induce to protect the population against infection.
Reference: Scheid JF, Mouquet H, Ueberheide B, Diskin R, Klein F, Oliveira TY, Pietzsch J, Fenyo D, Abadir A, Velinzon K, Hurley A, Myung S, Boulad F, Poignard P, Burton DR, Pereyra F, Ho DD, Walker BD, Seaman MS, Bjorkman PJ, Chait BT, Nussenzweig MC et al. Sequence and structural convergence of broad and potent HIV antibodies that mimic CD4 binding. Science. 2011 Sep 16;333(6049):1633-7.
Last Updated December 28, 2012
Last Reviewed December 28, 2012