title: Purified donor T cells alone activate transplantation immunity to the male antigen but induce tolerance in combination with Mac-1+ donor cells.
abstract: BACKGROUND
  In most experimental systems examined, "professional" antigen-presenting cells (APCs), such as dendritic cells, have been found to activate T cells, whereas "nonprofessional" antigen-bearing cells (nonAPC) may induce tolerance. Some recent studies have suggested that nonAPCs may under certain conditions prime a T-cell immune response. We have attempted to separate the roles of transplanted T cells and monocytic/dendritic cells in activating or tolerizing antigen-specific T cells in vivo, by examining the consequences of parenteral exposure to male antigen in anti-male TCR transgenic female mice.
  
  
  METHODS
  Qualitative and quantitative changes in the large population of male-reactive transgenic T cells to various male donor cell populations in transgenic female mice were followed after injections of highly purified male lymphoid cells. Changes in male-reactive T cells with time and the long-term outcome of male skin grafts were measured.
  
  
  RESULTS
  When a nonAPC population consisting of highly purified male T cells alone was injected intravenously into H-Y antigen-specific TCR transgenic female mice, the number of host transgenic T cells was sustainably increased, and male graft rejection was accelerated. Injection of a combination of purified T cells and purified Mac-l+ cells induced massive and permanent deletion of the host male-reactive T-cell population and permanent graft tolerance. Mac-l+ cells alone gave no appreciable change in responsive T cells or graft rejection times.
  
  
  CONCLUSIONS
  The data indicate that highly purified T cells engrafted alone induce rapid sensitization toward the male antigen. They also show that both male donor T cells and a population of male monocytic/ dendritic cells are required to induce peripheral tolerance toward this antigen and that this tolerance is related to permanent peripheral deletion of male-reactive T cells.
authors.affiliation: Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville 32610-0275, USA.
authors.forename: B
authors.initials: B
authors.lastname: Sheng
authors.forename: W T
authors.initials: WT
authors.lastname: McCormack
authors.forename: R T
authors.initials: RT
authors.lastname: Smith
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D005260:Female; D006084:Graft Rejection / Q000276:immunology; D006182:H-Y Antigen / Q000276:immunology*; D007108:Immune Tolerance / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D016177:Macrophage-1 Antigen / Q000276:immunology*; D008264:Macrophages / Q000276:immunology / Q000637:transplantation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D016038:Skin Transplantation / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000637:transplantation*
chemical_list: D006182:H-Y Antigen; D016177:Macrophage-1 Antigen; D016693:Receptors, Antigen, T-Cell, alpha-beta