SURVIVAL STRATEGIES OF LEISHMANIA-DONOVANI IN MAMMALIAN HOST MACROPHAGES

Microbes have evolved a variety of strategies to survive inside their host cells. Some have the molecular machinery to survive in the hostil e environment of phagolysosomes; others escape the phagosome to the mo re cozy environment of the cell cytoplasm; others inhibit the phagosom e fusion with hydrolase-enriched endocytic organelles. This is the cas e for the promastigote form of the protozoan parasite Leishmania donov ani which resides in a phagosome displaying poor fusogenic properties towards endosomes and lysosomes. Recent results indicate that the lipo phosphoglycan (LPG), the major cell surface molecule of Leishmania, is involved in the inhibition of phagosome maturation. Further studies i n our laboratories are addressing the molecular mechanisms of action o f LPG to modulate phagosome fusion properties and its effect on the bi ogenesis of phagolysosomes.