A team of researchers have identified an antibody that can potentially neutralize most strains of human immunodeficiency virus (HIV). The breakthrough may pave way for the development of a potential treatment.
Potent Antibody That Can Neutralize Most Strains Of HIV
In tests, Mark Connors, from the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH), and colleagues found that the antibody potently neutralized 98 percent of HIV isolates, which include 16 of 20 strains that are resistant to other antibodies of the same class.
To understand how the antibody developed its ability to neutralize almost all strains of HIV, the researchers also tracked how N6 evolved over time. The information they get can help in designing vaccines that can elicit broadly neutralizing antibodies.
Broadly Neutralizing Antibodies
It has not been easy to identify broadly neutralizing antibodies against HIV since the virus known to lead to Acquired Immunodeficiency Syndrome (AIDS) is capable of evading getting recognized by the immune system with its ability to rapidly change its surface proteins.
Six years ago, researchers from the Vaccine Research Center (VRC) of NIAID discovered the VRC01 antibody that can stop up to 90 percent of strains of HIV from infecting human cells. The newly identified antibody works similar to VRC01 when it comes to blocking infection. It binds to a part of the HIV envelope known as CD4 binding site and thus prevent the virus from attaching to the immune cells.
Researchers have found that the newly identified antibody evolved a unique mode of binding that focuses more on conserved regions that undergoes relatively little changes among HIV strain. It allows N6 to tolerate the changes in the HIV envelope that include mechanisms through which HIV develops resistance to most VRC01-class antibodies.
"N6 evolved a mode of recognition such that its binding was not impacted by the loss of individual contacts across the immunoglobulin heavy chain. In addition, structural analysis revealed that the orientation of N6 permitted it to avoid steric clashes with glycans, which is a common mechanism of resistance,: researchers wrote in their study, which was published in Immunity journal on Nov. 15.
Antibodies To Prevent And Treat HIV Infection
The findings suggest that N6 has advantages over VRC01, which is now being tested as an intravenous infusion to determine if it can safely prevent HIV infection. Because of its potency, N6 may have stronger and more durable benefits when it comes to preventing and treating HIV infection. It may also be administered subcutaneously instead of intravenously.