As mentioned above, an added challenge to Leishmania vaccine development is the large number of species, as well as the variability within species. Indeed, studies on the polymorphism of leading antigens such as GP63 quickly revealed that it was a very polymorphic [61, 62] . Such polymorphism has important implication for vaccine development as it may limit their efficacy against variant strains of parasites or novel escape mutants, and thus restrict vaccine protection to a single species [63, 64] . Antigen polymorphism between multiple strains and species is thus becoming a major issue in many vaccine development studies [65, 66] . In the case of Leishmania, few DNA vaccines have been tested against mul-tiple species. LACK antigen, initially identified in L. major, and found to be very conserved between Leishmania species, can protect mice against L. major [20] and L. amazonensis [67] , but not against L. mexicana [23] , L. donovani [25] , or L. chagasi [24] . On the other hand, L. amazonensis nuclease protein P4 can protect against both L. amazonensis and L. major, but cross-protection requires a different formulation (IL-12 or HSP70 as adjuvant, resp.) [38] . In other studies, antigens from one species were used to induce protection against another species [31] , but the extent of crossprotection against various species was not investigated. More recently, a single formulation of L. donovani NH36 DNA vaccine was found to induce a very good protection against both L. chagasi and L. mexicana, suggesting that this DNA vaccine may be able to provide broad protection against various Leishmania species [40] . Importantly, no DNA vaccine has yet been tested against L. braziliensis, in spite of this species being responsible of most cases of cutaneous leishmaniasis in South America.