An experimental HIV antibody tested on a group of monkeys showed to be effective as it suppressed the virus for nearly six months without additional treatment, researchers have found.

The findings lend a clue to strategies that attempt to achieve sustained, drug-free viral remission in people living with HIV, the Xinhua reported. The researchers may have targeted the viral reservoir -- populations of long-lived, latently infected cells that harbour the virus and that lead to resurgent viral replication when suppressive therapy was stopped, the study noted. "HIV excels at evading the immune system by hiding out in certain immune cells," said Anthony S. Fauci, Director at the National Institute of Allergy and Infectious Diseases (NIAID) in Maryland, US.

"The virus can be suppressed to very low levels with antiretroviral therapy, but quickly rebounds to high levels if a person stops taking medications as prescribed. The findings from this early stage research offer further evidence that achieving sustained viral remission without daily medication might be possible," he added, in a paper released at the 25th Conference on Retroviruses and Opportunistic Infections in Boston.

In the study, scientists infected rhesus macaques with simian-human immunodeficiency virus (SHIV), an HIV-like virus commonly used in nonhuman primate studies. They then initiated daily antiretroviral therapy (ART) for 96-weeks, during acute infection to suppress the virus to below detectable levels in the monkey's blood. After discontinuation of ART, the virus rebounded in the blood of all monkeys that neither received HIV antibodies or immune stimulant after a median of 21 days.

A group of monkeys who received the therapy combination showed a delayed viral rebound after a median of 112 days, another group did not rebound for at least 168 days. "Our findings suggest that the development of interventions to activate and eliminate a fraction of the viral reservoir might be possible," the researchers said. Compared with the antiretroviral therapy which needs to be taken daily, antibodies to HIV tend to last longer in the body and have shown promise for longer-acting HIV therapeutics and prevention modalities, they noted.