title: Antitumor effect of donor marrow graft rejection induced by recipient leukocyte infusions in mixed chimeras prepared with nonmyeloablative conditioning: critical role for recipient-derived IFN-gamma.
abstract: Some patients lose chimerism following nonmyeloablative hematopoietic cell transplantation (HCT), yet, surprisingly, enjoy sustained tumor remissions. We hypothesized that host-versus-graft (HVG) alloresponses might induce antitumor effects against recipient tumors. We explored this question in mice by administering recipient leukocyte infusions (RLIs) to mixed chimeras established with nonmyeloablative conditioning. Mixed chimeras were prepared in the B10.A (H2a)-->B6 (H2b) strain combination using depleting anti-T-cell monoclonal antibodies (mAbs), cyclophosphamide, and thymic irradiation. B6 myeloid leukemia cells (MMB3.19) were administered 7 days following donor lymphocyte infusion (DLI) or RLI on day 35. Conversion to full donor chimerism occurred without graft-versus-host disease (GVHD) following DLI, whereas RLI led to loss of chimerism. Both RLI and DLI significantly delayed tumor mortality. In another strain combination (B10.BR [H2k]-->BALB/c [H2d]), RLI-induced or spontaneous loss of chimerism was associated with antitumor effects against the host-type B-cell lymphoma A20. HCT was essential for the antitumor effect of RLI. RLI induced elevated serum interferon-gamma (IFN-gamma) levels, and recipient-derived IFN-gamma was critical for their antitumor effects. Thus, HVG reactions (spontaneous or induced by RLI) mediate antitumor effects against hematologic malignancies via a recipient-derived IFN-gamma-mediated mechanism. A novel approach to achieving anti-tumor effects without the risk of GVHD is suggested.
authors.affiliation: Transplantation Biology Research Center, Bone Marrow Transplantation Section, MGH-East Bldg 149-5102, Massachusetts General Hospital, Harvard Medical School, 13th Street, Boston, MA 02129, USA.
authors.forename: Marie-Therese
authors.initials: MT
authors.lastname: Rubio
authors.forename: Yong-Mi
authors.initials: YM
authors.lastname: Kim
authors.forename: Teviah
authors.initials: T
authors.lastname: Sachs
authors.forename: Markus
authors.initials: M
authors.lastname: Mapara
authors.forename: Guiling
authors.initials: G
authors.lastname: Zhao
authors.forename: Megan
authors.initials: M
authors.lastname: Sykes
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D017209:Apoptosis / Q000276:immunology; D016026:Bone Marrow Transplantation / Q000276:immunology*; D002455:Cell Division / Q000276:immunology; D002460:Cell Line; D005260:Female; D006084:Graft Rejection / Q000276:immunology*; D006789:Host vs Graft Reaction / Q000276:immunology; D007371:Interferon-gamma / Q000235:genetics / Q000276:immunology*; D015448:Leukemia, B-Cell / Q000276:immunology* / Q000401:mortality / Q000517:prevention & control; D017708:Leukocyte Transfusion; D016393:Lymphoma, B-Cell / Q000276:immunology / Q000401:mortality / Q000517:prevention & control; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D018183:Transplantation Chimera; D019172:Transplantation Conditioning
chemical_list: D000911:Antibodies, Monoclonal; D007371:Interferon-gamma