Mechanisms of Mycobacterium leprae-specific T-cell deficiency in lepromatous leprosy.
Patients suffering from lepromatous leprosy fail to develop an efficient cell-mediated immunity towards Mycobacterium leprae, the causative agent. The mechanism of such a specific T-cell tolerance to the bacillus remains a key question in the pathophysiology of leprosy. Macrophages do not show any intrinsic defect in phagocytizing and killing M. leprae or in presenting antigen to helper T-cells. On the other hand, M. leprae-reactive helper T-cells do persist in lepromatous patients, but their activation appears to prevented by active suppressor mechanisms, involving both suppressor T-cells and macrophages. The target of this specific suppression could be the interleukin 2-producing T-cell subset. A better molecular definition of M. leprae antigens, both by monoclonal antibodies and T-cell clones, should open new perspectives for further analysis of the regulation of immune responses to M. leprae.
Bach
M A
MA
Unité de Pathologie de l'Immunité, Institut Pasteur, Paris, France.
Launois
P
P
D007108:Immune Tolerance; D007153:Immunologic Deficiency Syndromes / Q000276:immunology*; D015440:Leprosy, Lepromatous / Q000209:etiology / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D009166:Mycobacterium leprae / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*