title: Cutting edge: B cells promote CD8+ T cell activation in MRL-Fas(lpr) mice independently of MHC class I antigen presentation.
abstract: Spontaneous CD8+ T cell activation in MRL-Faslpr mice is B cell dependent. It is unclear whether this B-dependent activation is mediated by direct Ag presentation via MHC class I proteins (i.e., cross-presentation) or whether activation occurs by an indirect mechanism, e.g., via effects on CD4+ cells. To determine how CD8+ T cell activation is promoted by B cells, we created mixed bone marrow chimeras where direct MHC class I Ag presentation by B cells was abrogated while other leukocyte compartments could express MHC class I. Surprisingly, despite the absence of B cell class I-restricted Ag presentation, CD8+ T cell activation was intact in the chimeric mice. Therefore, the spontaneous B cell-dependent CD8+ T cell activation that occurs in systemic autoimmunity is not due to direct presentation by B cells to CD8+ T cells.
authors.affiliation: Section of Immunobiology, Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, USA.
authors.forename: O T
authors.initials: OT
authors.lastname: Chan
authors.forename: M J
authors.initials: MJ
authors.lastname: Shlomchik
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000235:genetics*; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D001853:Bone Marrow / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007144:Immunoglobulin J-Chains / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000235:genetics; D008213:Lymphocyte Activation / Q000235:genetics*; D008211:Lymphocyte Cooperation / Q000235:genetics; D008231:Lymphopenia / Q000235:genetics / Q000276:immunology; D051379:Mice; D019463:Mice, Inbred MRL lpr; D011828:Radiation Chimera; D001613:beta 2-Microglobulin / Q000172:deficiency / Q000235:genetics / Q000276:immunology
chemical_list: D015395:Histocompatibility Antigens Class I; D007143:Immunoglobulin Heavy Chains; D007144:Immunoglobulin J-Chains; D007135:Immunoglobulin Variable Region; D001613:beta 2-Microglobulin