New Antibody Attacks 99% Of HIV Strains
Researchers from the National Institutes of Health (NIH) and the Paris-based pharmaceutical company Sanofi have engineered an antibody that protected monkeys from two strains of Human Immunodeficiency Virus (HIV) better than the equivalent naturally occurring antibodies. The results were published in the journal Science.
The “three-in-one” antibody protected monkeys from infection with two strains of SHIV, a monkey form of HIV. It also stopped a greater number of HIV strains from infecting cells in the laboratory more potently than natural, single antibodies.
The antibody binds to three different critical sites on HIV. The three HIV-binding segments of the antibody are based on three individual HIV antibodies, each of which powerfully neutralizes many strains of the virus. “We’re getting 99% coverage, and getting coverage at very low concentrations of the antibody,” said Dr Nabel.
“Combinations of antibodies that each bind to a distinct site on HIV may best overcome the defenses of the virus in the effort to achieve effective antibody-based treatment and prevention,” said Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases, part of NIH. “The concept of having a single antibody that binds to three unique sites on HIV is certainly an intriguing approach for investigators to pursue.”
The antibody was tested in an experiment involving monkeys and two strains of SHIV. One SHIV strain is sensitive to neutralization by VRC01 and the trispecific antibody, but resistant to neutralization by PGDM1400. The other SHIV strain is sensitive to neutralization by PGDM1400 and the trispecific antibody, but resistant to neutralization by VRC01. Scientists from the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston provided these SHIV strains.
The researchers are now planning to conduct early-phase clinical trials of the “trispecific” antibody in healthy people and in people living with HIV in the hope that it could eventually be used for long-acting HIV prevention and treatment. By binding to three different sites on the virus, the new antibody should be harder for HIV to dodge than natural, single antibodies.