[Defense mechanisms in trypanosomiasis].
Quantitative and functional alterations in macrophages are observed in trypanosomiasis. Two molecules from macrophages exert potent anti-microbial effect: Nitric Oxide (NO) and Tumor Necrosis Factor-alpha (TNF-alpha). The role of NO in trypanosomiasis is investigated at first on a murine parasite. Trypanosoma musculi, at first and then on Trypanosoma brucei gambiense and T. brucei brucei. Macrophages from T. musculi-infected mice synthesize NO and their trypanostatic activity is correlated with NO production. In vitro activation of macrophage NO synthase by IFN-gamma induces a trypanostatic activity and TNF-alpha is involved in NO synthase induction. High serum levels of TNF-alpha are correlated with disease severity in human African trypanosomiasis. TNF-alpha is increased in supernatants of leucocyte and trypanosome cocultures. TNF-alpha exerts a strong anti-trypanosomal effect. Messengers RNA of TNF-alpha are detected in monocytes after 8 hours of coculture with trypanosomes. Macrophage effector molecules participate with other immune effector mechanisms in resistance of host to trypanosomes.
D000818:Animals; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D007962:Leukocytes / Q000276:immunology; D008262:Macrophage Activation; D016215:Macrophage-Activating Factors / Q000276:immunology; D008264:Macrophages / Q000201:enzymology / Q000276:immunology; D051379:Mice; D009569:Nitric Oxide / Q000276:immunology / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000096:biosynthesis / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D014344:Trypanocidal Agents / Q000494:pharmacology; D014345:Trypanosoma; D014346:Trypanosoma brucei brucei / Q000187:drug effects; D014347:Trypanosoma brucei gambiense / Q000187:drug effects; D014352:Trypanosomiasis / Q000276:immunology*; D014353:Trypanosomiasis, African / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000235:genetics / Q000276:immunology
D016215:Macrophage-Activating Factors; D012333:RNA, Messenger; D014344:Trypanocidal Agents; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase
Mécanismes de défense au cours des trypanosomoses.