Vaccine prospects of killed but metabolically active Leishmania against visceral leishmaniasis.

Leishmanization or live vaccination, the gold standard for immunoprophylactic success against cutaneous leishmaniasis, has been abandoned for safety reasons. Killed but metabolically active (KBMA) Leishmania, a new class of whole-cell vaccine, holds promise for safe vaccination. Amotosalen (S-59)-treated and UVA-irradiated Leishmania major and Leishmania infantum chagasi (KBMA-Lic) were rendered replication-incompetent and incapable of causing disease; this was demonstrated convincingly by sensitive techniques. However, the immune response and the level of protection elicited by vaccination with both live Lic and KBMA-Lic in BALB/c mice are less than optimal and warrant further studies to establish their potentiality as an effective vaccine strategy against visceral leishmaniasis.