A prophylactic vaccine is a realistic goal
In endemic areas, most of the infected people do not develop clinical symptoms and past episode of leishmaniasis leads to lifelong immunity against re-infection with the same ubspecies, once the infection is healed. This leads to the assumption that the development of a vaccine is feasible. Even so, no such vaccine is available today.
Among the different Leishmania antigen preparations that have been investigated so far, a crude excretedsecreted antigen obtained from promastigote culture supernatant of Leishmania infantum gave highly promising results on dogs (dogs and humans being the main reservoirs of Leishmania). It induces a long lasting Th1-mediated protection against experimental and natural canine visceral leishmaniasis. The Promastigote Surface Antigen (PSA) protein was identified as the active constituent eliciting protective immunity. Research work is ongoing to define the smallest peptide sequence from PSA bearing immunodominant properties. As the PSA is present in all Leishmania species, the resulting vaccine could potentially protect population from the visceral and tegumentary leishmaniases forms caused by all Leishmania species. RAPSODI aims at turning such results into a human vaccine candidate ready for clinical trials.