New Broadly Neutralizing Antibody Effective Against 98% of HIV Strains

With one in eight people living with HIV in the United States alone, and 36.7 million people living with the virus worldwide, HIV remains a major threat to public health. However, researchers continue to make strides in the fight against the virus as they strive to develop a cure, which may be more within reach than previously thought.

Researchers at the National Institute of Allergy and Infectious Diseases (NIAID) at the National Institutes of Health have discovered a broadly neutralizing antibody (bNab), deemed N6, that possesses notable breadth and potency against the virus; it was effective against 98% of tested HIV-1 isolates, including strains (16/20) that have developed resistance to other antibodies of the same class, according to the study.

As indicated in the official press release, the research team sought to understand the evolution of the antibody and how it was able to successfully neutralize the isolates. According to study authors, “Such detailed information regarding the co-evolution of virus and antibody provides a potential pathway for generating such antibodies through vaccination.”

Previous to these findings, another well-known broadly neutralizing antibody, VRC01, was discovered in 2010 by NIAID’s Vaccine Research Center scientists. The VRC01 antibody had been able to neutralize 90% of HIV strains and, like N6, did so by binding to the CD4 binding site on the surface of the “HIV envelope,” preventing the cell from attaching to immune system cells. Both antibodies are able to prevent the virus from multiplying to some degree; however, there are differences pertaining to N6 that allow it to neutralize a larger percentage of the virus.

According to the press release, these differences lie in how N6 binds to the HIV envelope; rather than binding to the V5 region of the envelope, it binds to the “conserved regions” of the cell, which “change relatively little among HIV strains.” Due to this, N6 effectively avoids the region where “steric clashes with the glycosylated V5” occur, a mechanism that has been known to provide the virus with the ability to develop resistance to VRC01 and other such antibodies within its class.

Anthony S. Fauci, MD, NIAID Director, commented in the press release on the findings, saying, “The discovery and characterization of this antibody with exceptional breadth and potency against HIV provides an important new lead for the development of strategies to prevent and treat HIV infection.”