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HIV vaccine news: Antibody injection delays HIV-like infection

, by Emily Newman

May 18 is National HIV Vaccine Awareness Day—a day set aside to bring awareness and support to research dedicated to finding a safe and effective vaccine for HIV.    

vaccineA recent article published in Nature shared research showing that single monoclonal antibody injections are able to prevent an HIV-like infection when tested in monkeys. The researchers tested antibodies named VRC01, VRC01-LS, 3BNC117, and 10-1074 and found that single antibody therapies prevented infection in monkeys who were repeatedly exposed to an HIV-like virus (SHIV) over the course of months.

“If administered to populations at high risk of HIV-1 transmission, such an immunoprophylaxis regimen could have a major impact on virus transmission,” said Gautam and colleagues.

Broadly neutralizing antibodies prevent HIV from entering cells by attaching to proteins on the surface of virus particles. Once antibodies bind to HIV, it’s thought that they mark the virus for destruction by signaling the body’s natural immune defense system.

Read more about broadly neutralizing antibodies on BETA.

Experts hope that monoclonal antibody therapies could be used as an additional HIV prevention therapy for people at high risk for HIV infection. The current study offers some hope that this might be possible with a single, one-time injection.

Previous studies have established that 3BNC117, VRC01, and 10-1074 are broadly neutralizing—that is, they are effective against a broad range (up to 80%) of viral strains. The current study tested how well an infusion of each of these different antibodies, and a fourth improved-upon version of VRC01 named VRC01-LS, worked to prevent SHIV infection in monkeys who were rectally-exposed every week to SHIV.

Monkeys who did not receive an antibody infusion quickly seroconverted—within a median of 3 weeks.

In all cases, an antibody treatment delayed seroconversion. VRC01 delayed infection by a  median of 8 weeks; 10-1074 by 12.5 weeks; 3BNC117 by 13 weeks, and VRC01-LS by 14.5 weeks.

Although none of the therapies provided permanent protection against SHIV infection—as a vaccine might—the antibody infusions might be useful as an additional HIV prevention tool. “This might turn out to be a seasonal alternative to a vaccine until we really know how to make one,” said Malcolm Martin of the US National Institute of Allergy and Infectious Diseases, in an accompanying Nature article.

“This has the advantage over PrEP because you don’t have to worry every day — that’s the take-home point here,” said Martin.

Sources:

Gautam, R. and others. A single injection of anti-HIV-1 antibodies protects against repeated SHIV challenges. Nature. April, 2016.

Hayden, E. Antibody infusions provide long-term defence against HIV-like infection. Nature. April, 2016.

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