New research by amfAR grantee Dr. Dan Barouch and colleagues at Beth Israel Deaconess Medical Center in Boston further supports the idea that an HIV cure is likely to require a combination of agents rather than just one. It also offers further evidence of the potential role of antibodies in curing HIV.
Barouch’s study involved a group of macaque monkeys infected with SHIV, a combination of HIV and SIV (the simian form of the virus). The researchers found that those monkeys that had been given a broadly neutralizing antibody called PGT121 combined with an immunotherapeutic drug that may act as a latency-reversing agent experienced a significant delay to viral rebound after being taken off antiretroviral treatment. They also rebounded to lower levels of virus.
While the findings are extremely encouraging, the researchers cautioned that the results are very preliminary in relation to a cure for HIV. Dr. Barouch reported on his findings at the 2018 Conference on Retroviruses and Opportunistic Infections in Boston in February.
In a previous study reported in the August 2017 issue of the Journal of Virology, Dr. Barouch, along with colleagues from the Ragon Institute of MGH, MIT, and Harvard in Cambridge, MA, the National Institutes of Health in Bethesda, MD, and Leidos Biomedical Research and Frederick National Laboratory Center for Cancer Research in Frederick, MD, used a “passive immunization” approach to explore the potential role of antibodies in curing HIV infection.
This study also involved monkeys infected with SHIV. The monkeys were treated with either PGT121 or another antibody know to have anti-HIV properties called N6, a combination of both, or a placebo. The antibodies reduced the viral load in the monkeys.
The researchers then measured SHIV DNA in the blood and lymph nodes to see if the antibodies had any effect on infected cells. They found significantly reduced levels of SHIV DNA in the blood two weeks after the antibodies were administered; in the lymph nodes, SHIV DNA dropped markedly after 10 weeks.
These results suggest that passive immunization using these antibodies might, under the right conditions, kill cells of the persistent viral reservoir and thus play a role in curing HIV.