title: Role of immunoregulatory donor T cells in suppression of graft-versus-host disease following donor leukocyte infusion therapy.
abstract: In murine models of allogeneic bone marrow transplantation (BMT), MHC-mismatched recipients given a delayed infusion of donor leukocytes (DLI) at 21 days posttransplant develop significant GVHD whereas MHC-matched recipients do not. The current study was initially designed to test the hypothesis that small numbers of T cells in the MHC-mismatched donor bone marrow (BM) graft exacerbated graft-vs-host disease (GVHD) when DLI was administered at 21 days after BMT. Ex vivo depletion of Thy1+ cells from the donor BM had no impact on the severity of GVHD after DLI. However, depletion of donor T cells in vivo with a Thy1 allele-specific mAb given after BMT resulted in significantly more severe GVHD after DLI. Similar results were obtained in a MHC-matched model of allogeneic BMT, indicating that this was a general phenomenon and not model dependent. These results indicated that a population of donor-derived Thy1+ cells suppressed graft-vs-host reactivity after DLI. Results of experiments with thymectomized recipients demonstrated that an intact thymus was required for generation of the immunoregulatory donor cells. Experiments using TCR beta-chain knockout mice as BM donors indicated that the immunosuppressive Thy1+ cells coexpressed alphabetaTCR heterodimers. Similar experiments with CD4 and CD8 knockout donor BM suggested that the immunoregulatory Thy1+alphabetaTCR+ cells consisted of two subpopulations: a CD4+CD8- subpopulation and a CD4-CD8- subpopulation. Together, these results show that thymus-derived, Thy1+alphabetaTCR+ donor cells generated early after allogeneic BMT suppress the graft-vs-host reactivity of T cells given as DLI. These cells may mediate dominant peripheral tolerance after allogeneic BMT.
authors.affiliation: Department of Pediatrics, Medical College of Wisconsin, Milwaukee 53326, USA. bjohnson@mcw.edu
authors.forename: B D
authors.initials: BD
authors.lastname: Johnson
authors.forename: E E
authors.initials: EE
authors.lastname: Becker
authors.forename: J L
authors.initials: JL
authors.lastname: LaBelle
authors.forename: R L
authors.initials: RL
authors.lastname: Truitt
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage; D015704:CD4 Antigens / Q000096:biosynthesis; D016827:CD8 Antigens / Q000096:biosynthesis; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D006086:Graft vs Host Disease / Q000235:genetics / Q000276:immunology* / Q000517:prevention & control*; D006650:Histocompatibility Testing; D016130:Immunophenotyping; D007518:Isoantibodies / Q000008:administration & dosage; D017708:Leukocyte Transfusion / Q000009:adverse effects; D008213:Lymphocyte Activation; D018655:Lymphocyte Count; D008212:Lymphocyte Depletion; D008285:Major Histocompatibility Complex / Q000276:immunology; D051379:Mice; D008806:Mice, Inbred AKR; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011828:Radiation Chimera / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis; D013154:Spleen / Q000166:cytology / Q000637:transplantation; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D018800:Thy-1 Antigens / Q000096:biosynthesis / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D016827:CD8 Antigens; D007518:Isoantibodies; D016693:Receptors, Antigen, T-Cell, alpha-beta; D018800:Thy-1 Antigens; C035678:anti-Thy antibody