One of the many challenges with existing HIV therapies is that a dormant version of the virus is always in the background, ready to attack the immune system as soon as treatment is interrupted. Now, new research suggests that treatment with two anti-HIV antibodies immediately after infection enables the immune system to effectively control the virus, preventing its return for an extended period. The two drugs used in the study, 3BNC117 and 10-1074, belong to a class of molecules called broadly neutralizing antibodies, discovered in the same lab in studies of "elite controllers," people whose immune systems have a rare ability to fight off the virus with each antibody binding to a different site of the virus, preventing its damaging effects from different angles. "This form of therapy can induce potent immunity to HIV, allowing the host to control the infection, it works by taking advantage of the immune system's natural defenses, like what happens in some forms of cancer immunotherapy” says Michel Nussenzweig, head researcher on the project. The research was conducted in macaque monkeys, using a model of HIV infection called simian-human immunodeficiency virus. Although this model does not precisely mimic human HIV infection, the findings suggest that immunotherapy should be explored as a way of controlling the virus and boosting an immune response that can control the infection in people.