ABSTRACT
Although clinical studies have yet to demonstrate clearly the use of intravenous immunoglobulin (IVIG) for prevention of graft-versus-host disease (GVHD), their effective use in a xenogeneic mouse model has been demonstrated. We aimed to determine the mechanism of action by which IVIG contributes to GVHD prevention in a xenogeneic mouse model. NOD/LtSz-scidIL2rg(-/-) (NSG) mice were used for our xenogeneic mouse model of GVHD. Sublethally irradiated NSG mice were injected with human peripheral blood mononuclear cells (huPBMCs) and treated weekly with PBS or 50 mg IVIG. Incidence of GVHD and survival were noted, along with analysis of cell subsets proliferation in the peripheral blood. Weekly IVIG treatment resulted in a robust and consistent proliferation of human natural killer cells that were activated, as demonstrated by their cytotoxicity against K562 target cells. IVIG treatment did not inhibit GVHD when huPBMCs were depleted in natural killer (NK) cells, strongly suggesting that this NK cell expansion was required for the IVIG-mediated prevention of GVHD in our mouse model. Moreover, inhibition of T cell activation by either cyclosporine A (CsA) or monoclonal antihuman CD3 antibodies abolished the IVIG-induced NK cell expansion. In conclusion, IVIG treatment induces NK cell proliferation, which is essential for IVIG-mediated protection of GVHD in our mouse model. Furthermore, activated T cells are mandatory for effective IVIG-induced NK cell proliferation. These results shed light on a new mechanism of action of IVIG and could explain why the efficacy of IVIG in preventing GVHD in a clinical setting, where patients receive CsA, has never been undoubtedly demonstrated.
Subject(s)
Graft vs Host Disease/immunology , Killer Cells, Natural/immunology , Leukocytes, Mononuclear/transplantation , Animals , Disease Models, Animal , Graft vs Host Disease/chemically induced , Graft vs Host Disease/genetics , Graft vs Host Disease/pathology , Heterografts , Humans , K562 Cells , Killer Cells, Natural/pathology , Leukocytes, Mononuclear/pathology , Mice , Mice, Inbred NOD , Mice, Knockout , Mice, SCIDABSTRACT
BACKGROUND AIMS: Cytokine-induced killer (CIK) cells may represent a promising immunotherapy for the treatment of children with relapsing B-lineage acute lymphoblastic leukemia (B-ALL) following hematopoietic stem cell transplantation (HSCT). Therefore, we investigated the possibility of combining adoptive immunotherapy with CIK cells and human interferon-alpha (hIFN-α) in order to potentiate the cytotoxicity of CIK cells against B-ALL. METHODS: Cord blood- derived CIK (CB-CIK) cells were differentiated, stimulated with phosphate-buffered saline (PBS) or hIFN-α, and tested for cytotoxic activity. We tested the anti-leukemic and graft-versus-host disease (GvHD) effects of CB-CIK cells in a human xenograft NOD/SCID/γc(-) (NSG) mouse model. RESULTS: Bulk CB-CIK cells showed very moderate cytotoxic activity while the subpopulation of CD56(+) CB-CIK cells showed significant cytotoxic activity against B-ALL cells. hIFN-α significantly augmented the cytotoxicity of CD56(+)CB-CIK cells in vitro and induced signal transducer and activator of transcription-1 (STAT1) phosphorylation. In addition, CD56(+)CB-CIK cells could delay mouse mortality significantly in vivo, and this effect was enhanced significantly by hIFN-α (P = 0.022). Furthermore, unlike CB mononuclear cells or peripheral blood mononuclear cells (PBMC), CD56(+)CB-CIK cells, alone or stimulated with hIFN-α, caused either no GvHD or mild GvHD, respectively, when injected into sublethally irradiated NSG mice. CONCLUSIONS: CD56(+)CB-CIK cells are effective cytotoxic agents against human B-ALL cell lines in vitro and possess anti-leukemic activity that is potentiated by hIFN-α in an NSG mouse model in vivo. These pre-clinical data support the testing of this immunotherapeutic approach in the clinic for the treatment of B-ALL.
Subject(s)
CD56 Antigen/metabolism , Cytokine-Induced Killer Cells/immunology , Cytotoxicity, Immunologic/drug effects , Fetal Blood/cytology , Interferon-alpha/pharmacology , Leukemia, Lymphocytic, Chronic, B-Cell/immunology , Leukemia, Lymphocytic, Chronic, B-Cell/therapy , Animals , Antigens, CD/metabolism , Antigens, Differentiation, T-Lymphocyte/metabolism , Cell Line, Tumor , Cytokine-Induced Killer Cells/drug effects , Disease Models, Animal , Graft vs Host Disease/immunology , Humans , Lectins, C-Type/metabolism , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Mice , Phosphorylation/drug effects , STAT1 Transcription Factor/metabolism , TNF-Related Apoptosis-Inducing Ligand/metabolism , Xenograft Model Antitumor AssaysABSTRACT
Human mesenchymal stromal cells (MSCs) have been successfully utilized for the treatment of refractory graft-versus-host disease (GvHD). Despite the large number of in vitro and in vivo models developed for clarifying their immunomodulatory properties, the mechanism of action of MSCs remains elusive and their efficacy controversial. Here, we tested the ability of cord blood-derived MSCs to alleviate the symptoms of GvHD induced by the injection of human peripheral blood mononuclear cells into NOD/SCID/γc(-) mice. In this in vivo xeno-GvHD model, we demonstrate that a single MSC injection is able to inhibit GvHD in terms of clinical signs and related mortality. We also show that in this model MSCs act by both immunomodulating T-cells and fostering recovery after irradiation. The translational impact of these findings could provide a reliable preclinical model for studying the efficacy, dosage, and time of administration of human MSCs for the prevention of acute GvHD.
