title: MiHA reactive CD4 and CD8 T-cells effect resistance to hematopoietic engraftment following reduced intensity conditioning.
abstract: Reduced intensity conditioning (RIC) prior to allogeneic hematopoietic cell transplantation (HCT) has shown promise in lowering the incidence of post-transplant complications including infection and graft-versus-host disease. T-cell-mediated graft rejection, however, remains a crucial factor in determining how 'mild' a level of immunosuppression can be administered. Understanding the kinetics of resistance responses as well as the role of CD4+ and CD8+ T cells underlies the development of protocols to circumvent resistance and support hematopoietic engraftment. In these studies, a major histocompatibility complex (MHC)-matched/minor histocompatibility antigen (MiHA) disparate RIC HCT model was developed in which resistance against donor hematopoietic progenitors as well as mature peripheral blood cells could be assessed. Interestingly, resistance was diminished in the absence of either host CD4+ or CD8+ T cells. However, its impairment was more severe in CD4-/- mice where resistance was not detected. Host CD4+ T cells were required for optimal expansion of specific (H60) T-cell receptor (TCR) expressing host anti-donor MiHA reactive CD8+ T cells following HCT. These observations demonstrate a critical role for host CD4+ T cells in resistance against MiHA disparate HCT. This RIC HCT resistance model will be useful for the analysis of the barrier to engraftment mediated by host T cells and the development of strategies to support engraftment.
authors.affiliation: Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, Florida, USA.
authors.forename: Z F
authors.initials: ZF
authors.lastname: Zimmerman
authors.forename: R B
authors.initials: RB
authors.lastname: Levy
mesh_terms: D000818:Animals; D016026:Bone Marrow Transplantation; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D006085:Graft Survival / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D015778:Minor Histocompatibility Antigens / Q000276:immunology* / Q000378:metabolism; D014019:Tissue Donors; D019172:Transplantation Conditioning; D014181:Transplantation Immunology; D014184:Transplantation, Homologous
chemical_list: D015778:Minor Histocompatibility Antigens