NEW YORK (TIP): Scientists have found a new way to clean the remaining human immunodeficiency virus (HIV) from the bodies of infected patients after they have been treated with antiretroviral therapy.

Scientists used radioimmunotherapy (RIT) to destroy remaining human immunodeficiency virus (HIV)-infected cells in the blood samples of patients treated with antiretroviral therapy, offering the promise of a strategy for curing HIV infection. Ekaterina Dadachova from Albert Einstein College of Medicine in the Bronx, New York and a team of researchers administered RIT to blood samples from 15 HIV patients treated with highly active antiretroviral therapy (HAART).

RIT, which has historically been employed to treat cancer, uses monoclonal antibodies – cloned cells that are recruited by the immune system to identify and neutralise antigens. “In RIT, the antibodies bind to the infected cells and kill them by radiation. When HAART and RIT are used together, they kill the virus and the infected cells, respectively,” said Dadachova, the study’s lead author.

Dadachova’s team paired the monoclonal antibody (mAb2556) designed to target a protein expressed on the surface of HIV-infected cells with the radionuclide Bismuth-213. Researchers found that RIT was able to kill HIV-infected lymphocytes previously treated with HAART, reducing the HIV infection in the blood samples to undetectable levels.

“The elimination of HIV-infected cells with RIT was profound and specific. The radionuclide we used delivered radiation only to HIVinfected cells without damaging nearby cells,” Dadachova said. An important part of the study tested the ability of the radiolabeled antibody to reach HIV-infected cells in the brain and central nervous system. Using an in vitro human blood brain barrier model, the researchers demonstrated that radiolabeled mAb2556 could cross the blood brain barrier and kill HIV-infected cells without any overt damage to the barrier itself.