Studies suggest that monoclonal antibodies (mAbs) that block inhibitory receptors on immune cells can enhance the immune responses against cancer, but the intravenous injection of such mAbs has caused severe side effects in animals and humans. In our laboratory, we have developed a method to deliver mAbs and other proteins that block such inhibitory receptors locally at the site where immune responses against melanoma proteins are stimulated by vaccination, enhancing anti-melanoma immunity while avoiding the side-effects associated with intravenous injection of these immune modulators. This is achieved by loading dendritic cells, a type of immune cell, with RNA that encodes the immune modulator. The RNA-loaded dendritic cells then make the immune modulatory proteins and release them locally. By mixing these dendritic cells with additional dendritic cells loaded with melanoma proteins, the immune modulators are released at the site where anti-melanoma immune cells are stimulated.