Immunology of canine leishmaniasis.

The role of dogs as the main reservoir of visceral leishmaniasis has led to an increased interest in the immune responses and in Leishmania antigens implicated in protective cellular immunity in canine visceral leishmaniasis. The primary goal is to control the prevalence of human disease. Immune responses in canine visceral leishmaniasis are reviewed. Cellular immune responses toward a Th1 subset mediated by IFN-gamma and TNF-alpha predominate in asymptomatic dogs exhibiting apparent resistance to visceral leishmaniasis. On the other hand, while the role of Th2 cytokines, such as IL-4 and IL-10, in symptomatic animals is still controversial, there is increasing evidence for a correlation of these cytokines with progressive disease. CD8+ cytotoxic T cells seem also likely to be involved in resistance to visceral leishmaniasis. Several Leishmania antigens implicated in protective immune responses are described and some pivotal points for development of an effective vaccine against canine visceral leishmaniasis are discussed.