Alpha beta TCR+ cells are a minimal fraction of peripheral CD8+ pool in MHC class I-deficient mice.
MHC class I molecules play a role in the maintenance of the naive peripheral CD8+ T cell pool. The mechanisms of the peripheral maintenance and the life span of residual CD8+ cells present in the periphery of beta 2-microglobulin-deficient (beta 2m-/-) mice are unknown. We here show that very few CD8+ cells in beta 2m-/- mice coexpress CD8 beta, a marker of the thymus-derived CD8+ T cells. Most of the CD8 alpha+ cells express CD11c and can be found in beta 2m/RAG-2 double-deficient mice, demonstrating that these cells do not require rearranged Ag receptors for differentiation and survival and may be of dendritic cell lineage. Rare CD8 alpha+CD8 beta+ cells can be detected following in vivo alloantigenic stimulation 2 wk after the adult thymectomy. Selective MHC class I expression by bone marrow-derived cells does not lead to an accumulation of CD8 beta+ cells in beta 2m-/- mice. These findings demonstrate that 1) thymic export of CD8+ T cells in beta 2m-/- mice is reduced more severely than previously thought; 2) non-T cells expressing CD8 alpha become prominent when CD8+ T cells are virtually absent; 3) at least some beta 2m-/- CD8+ T cells have a life span in the periphery comparable to wild-type CD8+ cells; and 4) similar ligands induce positive selection in the thymus and survival of CD8+ T cells in the periphery.
Michael Heidelberger Division of Immunology, Department of Pathology and Kaplan Comprehensive Cancer Center, New York University School of Medicine, New York, NY 10016, USA.
D
D
Nesić
F R
FR
Santori
S
S
Vukmanović
D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D015415:Biomarkers; D001854:Bone Marrow Cells / Q000276:immunology / Q000378:metabolism; D016827:CD8 Antigens / Q000096:biosynthesis / Q000235:genetics; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D019070:Cell Lineage / Q000235:genetics / Q000276:immunology; D016922:Cellular Senescence / Q000235:genetics / Q000276:immunology; D004847:Epithelial Cells / Q000276:immunology / Q000378:metabolism; D005260:Female; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis / Q000235:genetics*; D008213:Lymphocyte Activation / Q000235:genetics; D018655:Lymphocyte Count; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis*; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism*; D001613:beta 2-Microglobulin / Q000096:biosynthesis / Q000172:deficiency* / Q000235:genetics*
D015415:Biomarkers; D016827:CD8 Antigens; D015395:Histocompatibility Antigens Class I; D016693:Receptors, Antigen, T-Cell, alpha-beta; D001613:beta 2-Microglobulin