Just one injection of long-lasting, HIV-targeting antibodies protects monkeys from HIV infection for up to 20 weeks, reports a paper published online this week in Nature Medicine. This result supports the development of an intermittent prophylactic injection of antibodies for prevention of HIV infection.
Despite more than 30 years of research, there is no vaccine or cure for HIV. Research into HIV-specific immune responses, however, shows that individuals with HIV can develop antibodies that block infection by a broad range of viral strains. These antibodies are being clinically tested for use in controlling virus levels in individuals who are HIV-positive, and they are being preclinically tested in monkeys to determine whether they can prevent infection.
Now, Malcolm Martin and colleagues report that monkeys can be protected from simian HIV (SHIV) infection in the long term with a single injection of antibodies. The injection was developed by modifying two distinct HIV-neutralizing antibodies, which enabled them to remain in the bloodstream for two- to four-times longer than unmodified antibodies. The injection of the modified antibodies protects most animals from SHIV for a median of 20 weeks when administered as a combination subcutaneous injection.
The ability to induce durable protection from HIV infection with a single injection lays the groundwork for developing antibodies for use as an annual or biannual pre-exposure prophylactic in the absence of an HIV vaccine.