Protective immunity against malaria: cellular changes in the liver vary according to the method of immunization

Characterization of cells present in the extravascular compartment of murine liver was performed after different immunization procedures against the malaria parasite Plasmodium yoelii. Mice were immunized with live or irradiated sporozoites or with parasitized erythrocytes. Whatever the immunization protocol used, the mice were protected against a sporozoite challenge but each immunization procedure induced a specific profile of cell types. Immunization with irradiated sporozoite induce a significant increase in CD8+ lymphocytes, parasitized erythrocytes stimulates production of monocytes/macrophages and CD8+ lymphocytes while, after live sporozoites immunization, polymorphonuclear cells, macrophages/ monocytes, B cells and a range of T cell subsets were increased in number.