title: Leishmania major: analysis of lymphocyte and macrophage cellular phenotypes during infection of susceptible and resistant mice.
abstract: Genetically susceptible BALB/c and resistant C57BL/6 mice were infected with Leishmania major and the phenotypes of the responding cells in the draining lymph nodes and cutaneous lesions were analyzed. As early as 1 week, significantly increased numbers of L3T4+ cells as compared to Lyt-2+ cells were present in BALB/c mice lymph nodes (P less than 0.005). Increases in L3T4+ and Lyt-2+ cells were comparable in C57BL/6 mice, resulting in threefold lower L3T4/Lyt-2 ratio than in BALB/c mice. T cell subsets were activated in both strains to express interleukin-2 receptor (IL2R) above resting values, although greater numbers of activated L3T4+ cells were present in the draining lymph nodes from BALB/c at 1 and 3 weeks of infection than in C57BL/6 (P = 0.02). Despite the presence of activated L3T4+ cells in both strains, macrophages differed in the expression of immunologically important surface molecules during infection. Tissue macrophages from BALB/c mice were IgG1/G2b Fc receptor (FcR)+ and Ia- late in disease, whereas macrophages in C57BL/6 became FcR and Ia during healing. BALB/c mice, treated with monoclonal antibody GK1.5 to transiently deplete L3T4+ cells, became resistant to subsequent infection and developed a macrophage phenotype that was FcR- and Ia+. These differences in macrophage phenotype were closely linked to susceptibility during infection with L. major and may play a role in the pathophysiology of murine leishmaniasis.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D002452:Cell Count; D004198:Disease Susceptibility; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D007113:Immunity, Innate; D007895:Leishmania tropica / Q000235:genetics / Q000276:immunology*; D007896:Leishmaniasis / Q000235:genetics / Q000276:immunology* / Q000469:parasitology; D008198:Lymph Nodes / Q000276:immunology*; D008214:Lymphocytes / Q000276:immunology*; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010641:Phenotype; D011961:Receptors, Fc / Q000032:analysis; D011971:Receptors, Immunologic / Q000032:analysis; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000949:Histocompatibility Antigens Class II; D011961:Receptors, Fc; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2