Two studies released Wednesday suggest an antibodies treatment may one day be able to control a patient's HIV infection.

Researchers from Harvard and the Beth Israel Deaconess Medical Center in Boston used lab-made versions of antibodies to fight an HIV cousin (SHIV) in rhesus monkeys.

Thirteen of the study's eighteen animals showed undetectable viral loads within a week of the treatment, but the virus returned within three months. The virus remained undetectable for up to eight months after treatment in three monkeys with the lowest levels of SHIV before treatment. In two monkeys with the highest levels of SHIV, the virus was reduced but not to an undetectable point.

Similar results were found in a smaller study conducted by Dr. Steven Deeks of the University of California, San Francisco and Dr. Louis Picker of the Oregon Health & Science University in Beaverton.

Both studies were published in the journal Nature.

Researchers said they were encouraged by the results. Dr. Deeks, however, told The New York Times that the studies “raised more questions than they answered. But that's how science advances.”