title: [Importance of the different T lymphocytes subsets in immunity of mice against an intracellular protozoan parasite: Leishmania major].
abstract: The resolution of lesions in mice experimentally infected with L. major requires the expansion of CD4+ T cells specific for parasite antigens which release or express on their membranes lymphokines typical of those secreted by CD4+ Th1 cells. These lymphokines activate macrophages containing L. major to a parasiticidal state through the production of molecules toxic for the parasite. The anti-Leishmania effector function of parasite-specific CD4+ Th1 cells was found dependent upon their fine specificity. Specific CD8+ T cells are induced during infection and evidence exist that they contribute to the elimination of parasites, an effect probably resulting from the Interferon gamma that they release. Their role in controlling secondary lesions that develop upon challenge of immune mice is even more important. The severity of lesions induced by L. major in mice depends upon the expansion of parasite-specific CD4+ cells with functional characteristics of Th2 cells. This effect appears to be the result of their ability to secrete lymphokines capable of inhibiting the activation of macrophages in response to IFN-gamma and the secretion of this lymphokine by Th1 cells. Recently, a possible role for gamma delta+ T cells in containing parasites growth in vivo has been suggested.
authors.affiliation: Centre OMS de Recherche et Formation en Immunologie, Institut de Biochimie, Université de Lausanne, Epalinges, Suisse.
authors.forename: J A
authors.initials: JA
authors.lastname: Louis
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D016827:CD8 Antigens / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D018320:Leishmania major / Q000276:immunology* / Q000302:isolation & purification; D016773:Leishmaniasis, Cutaneous / Q000276:immunology* / Q000469:parasitology; D008222:Lymphokines / Q000096:biosynthesis / Q000276:immunology*; D008262:Macrophage Activation; D051379:Mice
chemical_list: D016827:CD8 Antigens; D008222:Lymphokines; D015847:Interleukin-4; D007371:Interferon-gamma
vernacular_title: Importance des différentes sous-populations de lymphocytes T dans l'immunité de la souris vis-à-vis d'un parasite protozoaire intracellulaire: Leishmania major.