Scientists have discovered an antibody produced by an HIV-positive patient that neutralizes 98 percent of all HIV strains tested, including most of the strains that are resistant to other antibodies of the same class.
Due to HIV’s ability to rapidly respond to the body’s immune defenses, an antibody that can block a wide range of strains has been very hard to come by.
Researchers from the US National Institutes of Health found that the antibody, called NG, was able to maintain its ability to recognize the HIV virus, even as the virus morphed and broke away from it.
It’s also up to 10 times more potent than VRC01, an antibody in the same class as N6, which has progressed to phase II clinical trials in human patients, after protecting monkeys against HIV for nearly six months.
“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,” said Anthony S. Fauci from the US National Institute of Allergy and Infectious Diseases.
An antibody is a protein produced by the immune system in response to harmful pathogens such as bacteria and viruses.
When the researchers exposed N6 to 181 different strains of HIV, it managed to destroy 98 percent of them, including 16 of 20 strains resistant to other antibodies of the same class.
That’s a significant step up from the VRC01 antibody, which stops up to 90 percent of HIV strains from infecting human cells.
“However, the discovery of the N6 antibody demonstrates that this new VRC01-class antibody can mediate both extraordinary breadth and potency even against isolates traditionally resistant to antibodies in this class.”
The researchers tracked its evolution over time to see how it responded to the shape-shifting defenses of the HIV virus and found that it relied less on binding with parts of the virus that are prone to changing, known as the V5 region, and more on parts that change very little across different strains.
They also found that mutations of the HIV virus that happened to be resistant to N6 rarely cropped up, which suggests that the virus couldn’t respond to this antibody as quickly as it has with other treatments scientists have discovered recently.