Dr. Jones has studies on Leishmania amazonensis that contribute to the global disease, leishmaniasis. This disease can have a variety of symptoms from skin ulcers and organ disease to facial disfigurations and immune system malfunctions with more than two million new cases a year. It is transmitted to mammals through the bite of an infected female sand fly and tends to be confined to the tropical and subtropical regions of the world. Current studies are examining the role of the parasite in inhibiting IL-12 production, and determining what host factors influence the IL-12 responsiveness of the CD4+ T cell response during L. amazonensis infection. The long-term goal of this work is to determine how the parasite inhibits the development of an effective cell-mediated immune response in the presence of high parasite numbers. This understanding will lead to methods of immunomodulation that can be used for vaccination strategies or alter the host immune response in the presence of a chronic infection. The principles of immune evasion that these parasites employ are probably not unique to Leishmania and will be applicable to other pathogens of chronic infectious diseases, such as mycobacteria. He also is examining novel vaccine modalities via immunologic and engineering technology.