Induction of partial protection against Leishmania major in BALB/c mice by Leishmania tropica

Leishmaniasis is a parasitic disease of man and other mammals. Immunity against leishmaniasis appears to remain essentially species specific; however some cross-reactivity has been reported. The aim of this study was analyzing cross-protection induced by Leishmania tropica (L. tropica) against Leishmania major (L. major). BALB/c mice were infected with L. tropica in the footpad followed by a challenge infection in the contra lateral footpad by L. tropica or L. major. Footpad thickness and parasite load in the footpad, popliteal lymph node, and spleen were determined after challenge. The results demonstrate that L. tropica induces partial protection of BALB/c mice against L. tropica as well as L. major. The protection was more efficient against a homologous strain (L. tropica) than against a heterologous strain (L. major). The partial protection against L. major was detected in the footpad tissues as well as popliteal lymph node. No protection was observed against L. major in the spleen tissue. These findings have implications in vaccination strategies for Leishmaniasis based on the use of heterologous species of the parasite.