Vaccine Development for Human Leishmaniasis

The development of vaccines for human leishmaniasis is one of the most important approaches for effectively controlling and/or eradicating the several forms of the disease. Based on the knowledge obtained from the practice of leishmanization and its protective immune response, several strategies have been used to develop vaccines against Leishmania species, such as the use of whole killed and attenuated parasites, recombinant proteins, and DNA vaccines. An ideal vaccine should be safe, effective, and immunogenic. Although several candidates have achieved safety and some level of effectiveness, the current challenge in the development of prophylactic vaccines is to achieve long-lasting immune protection by generating a robust and irreversible Th1 adaptive immune response in the host, with rapid recruitment of memory and effectors T cells at key acute points of infection. However, despite all efforts over the years, due to the antigenic diversity of the parasite and the complexity of the host’s immune response, human vaccine trials have been disappointing in mediating long-term immunity against sandfly-delivered infection. Therefore, more investments in this field should be carried out to translate preclinical findings from mice to humans through effective vaccine development strategies.