A controversial vaccine against HIV, the virus that causes AIDS, has been shown to stimulate a critical part of the HIV-specific immune response in chronically infected patients. The small study conducted by researchers at Massachusetts General Hospital (MGH) finds that a vaccine made from an inactivated form of the AIDS virus (Remune) induces the proliferation of CD4 cells ? also called T helper cells ? that specifically target HIV. Appearing in the June issue of the journal AIDS, the study is the first clear demonstration of the potential reconstitution of the immune response in chronic HIV infection. However, this pilot study was not designed to tell whether or not the vaccine would have any effect on the eventual course of the disease.