Leishmania and the macrophage: a multifaceted interaction.

Leishmania, the causative agent of leishmaniases, is an intracellular parasite of macrophages, transmitted to humans via the bite of its sand fly vector. This protozoan organism has evolved strategies for efficient uptake into macrophages and is able to regulate phagosome maturation in order to make the phagosome more hospitable for parasite growth and to avoid destruction. As a result, macrophage defenses such as oxidative damage, antigen presentation, immune activation and apoptosis are compromised whereas nutrient availability is improved. Many Leishmania survival factors are involved in shaping the phagosome and reprogramming the macrophage to promote infection. This review details the complexity of the host-parasite interactions and summarizes our latest understanding of key events that make Leishmania such a successful intracellular parasite.