CD25 is a marker for CD4+ thymocytes that prevent autoimmune diabetes in rats, but peripheral T cells with this function are found in both CD25+ and CD25- subpopulations.
Previously we have shown that autoimmune diabetes, induced in rats by a protocol of adult thymectomy and split-dose gamma irradiation, can be prevented by the transfer of a subset of CD4+ T cells with a memory phenotype (CD45RC-), as well as by CD4+CD8- thymocytes, from syngeneic donors. Further studies now reveal that in the thymus the regulatory cells are observed in the CD25+ subset of CD4+CD8- cells, whereas transfer of the corresponding CD25- thymocyte subset leads to acceleration of disease onset in prediabetic recipients. However, in the periphery, not all regulatory T cells were found to be CD25+. In thoracic duct lymph, cells that could prevent diabetes were found in both CD25- and CD25+ subsets of CD4+CD45RC- cells. Further, CD25- regulatory T cells were also present within the CD4+CD45RC- cell subset from spleen and lymph nodes, but were effective in preventing diabetes only after the removal of CD25- recent thymic emigrants. Phenotypic analysis of human thymocytes showed the presence of CD25+ cells in the same proportions as in rat thymus. The possible developmental relationship between CD25+ and CD25- regulatory T cells is discussed.
Stephens
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Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom. leighs@molbiol.ox.ac.uk
Mason
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D019264:Adoptive Transfer; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation; D016827:CD8 Antigens / Q000096:biosynthesis; D002454:Cell Differentiation / Q000276:immunology; D002465:Cell Movement / Q000276:immunology; D002469:Cell Separation; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology* / Q000517:prevention & control*; D005260:Female; D007156:Immunologic Memory; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D008212:Lymphocyte Depletion; D011828:Radiation Chimera / Q000276:immunology; D051381:Rats; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis / Q000502:physiology*; D013154:Spleen / Q000166:cytology / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation; D013897:Thoracic Duct / Q000166:cytology / Q000276:immunology; D013934:Thymectomy; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation
D015415:Biomarkers; D016827:CD8 Antigens; D015375:Receptors, Interleukin-2