Research paperPathways leading to interleukin-12 production and protective immunity in cutaneous leishmaniasis

•IL-12 plays a key role in protective immunity in cutaneous leishmaniasis.•CD40-CD40L interaction is the major pathway leading to IL-12 production in cutaneous leishmaniasis.•There are compensatory pathways for IL-12 production in the absence of CD40-CD40L interaction.

Leishmaniasis affects millions of people worldwide and continues to pose public health problem. There is extensive evidence supporting the critical role for IL-12 in initiating and maintaining protective immune response to Leishmania infection. Although gene deletion studies show that CD40-CD40L interaction is an important pathway for IL-12 production by antigen-presenting cells and subsequent development of protective immunity in cutaneous leishmaniasis, several studies have uncovered other pathways that could also lead to IL-12 production and immunity in the absence of intact CD40-CD40L signaling. Here, we review the literature on the role of IL-12 in the induction and maintenance of protective T cell-mediated immunity in cutaneous leishmaniasis and the different pathways leading to IL-12 production by antigen-presenting cells following Leishmania major infection.