Biologie comparée des interactions entre les macrophages et Trypanosoma cruzi, Leishmania spp. et Toxoplasma gondii

Macrophages have a central role in the immune system by eliminating a lot of pathogens. Nevertheless, they are often infected by pathogenic microorganisms in particular parasitic protozoa. They thus play the role of host cell by harbouring the intracellular survival and multiplication of these pathogens. Various mechanisms (receptors/ligands interactions, enzymes…) are involved in recognition and adhesion steps. When suitably activated, they become effector cells and they can control infection at least partially through the production of reactive oxygen derivatives. But parasitic protozoa can escape these defence mechanisms. In addition, macrophages are also antigen presenting cells and they are inductor cells of the immune response. Once again, parasitic protozoa interfere with these functions and induce chronic infections. Biology of Trypanosoma cruzi, Leishmania spp. and Toxoplasma gondii will be briefly reviewed to illustrate these various aspects of cellular parasitism.