Yerkes National Primate Research Center researchers in collaboration with Institut Pasteur have determined a combination immunotherapy of Interleukin-21 (IL-21) and interferon alpha (IFNα) when added to antiviral therapy (ART) is effective in generating highly functional natural killer (NK) cells that can help control and reduce simian immunodeficiency virus (SIV) in animal models. This finding, published online today in Nature Communications, is key for developing additional treatment options to control HIV/AIDS, which impacts 38 million people worldwide.