Researchers at the University of Pennsylvania have discovered a “central memory” form of “helper” T cells that can offer immunity to leishmaniasis, a disease that causes considerable death and disfigurement across the globe and has been found in U.S. military personnel returning from Afghanistan and Iraq.In the October issue of Nature Medicine, the Penn researchers describe how the discovery can offer immunity to leishmaniasis, even without the persistent presence of the parasite that caused the disease. Their findings encourage a new approach to creating a vaccine against leishmaniasis and other immune cell mediated diseases such as tuberculosis and HIV/AIDS.Attempts to create a vaccine for leishmaniasis have long been stymied by the fact that the helper T cells, which coordinate the immune response against a pathogen, need constant stimulation from the pathogen in order to remain effective against the disease.