CD80-Transfected acute myeloid leukemia cells induce primary allogeneic T-cell responses directed at patient specific minor histocompatibility antigens and leukemia-associated antigens.
Despite sufficient levels of HLA class I and class II expression, acute myeloid leukemia (AML) cells usually fail to induce a significant T-cell response in vitro. Therefore, we investigated whether in vitro modifications could enhance the T-cell stimulatory properties of AML cells. AML cells were either cultured with granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-4 (IL-4), and tumor necrosis factor-alpha (TNF-alpha), or transfected with the CD80 (B7.1) gene and used as stimulator cells for primed and unprimed allogeneic T cells. Cytokine treatment increased HLA class I and II expression, but did not induce CD80 on AML cells. Cytokine-treated AML cells efficiently presented nominal and allo-antigens to primed T-cell clones, induced strong T-cell proliferation in HLA mismatched mixed lymphocyte reactions (MLR), but failed to induce primary T-cell responses from an HLA identical bone marrow donor in MLR. In contrast, CD80-transfected AML cells induced T-cell proliferation of HLA-identical bone marrow donor peripheral blood mononuclear cell (PBMC) in primary MLR, allowing the generation of leukemia reactive CD4(+) T-cell lines and clones. The majority of the generated oligoclonal (25 of 35) T-cell cultures showed patient specific reactivity that did not discriminate between patient's leukemic cells and Epstein-Barr virus (EBV)-transformed B cells (EBV-LCL). The remaining 10 oligoclonal T-cell cultures recognized only leukemic cells. One of these latter leukemia reactive oligoclonal T cells was cloned. The majority of the clones (25 of 29) reacted against both leukemic cells and patient's EBV-LCL. A minority of the T-cell clones with the CD4 phenotype (four of 29) showed strong HLA-DP restricted reactivity against leukemic cells, but not against patient's EBV-LCL or against HLA-matched nonleukemic cells, indicating that their target antigens are preferentially expressed by leukemic cells. In conclusion, our study shows that the in vitro allogeneic T-cell response induced by CD80-transfected AML cells is mainly directed against patient's specific minor histocompatibility antigens, while antigens preferentially expressed by leukemic cells can also trigger T-cell responses.
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Department of Immunohematology and Blood Bank, Leiden University Medical Center, Leiden, The Netherlands.
Schrama
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Melief
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Goulmy
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D000951:Antigens, Neoplasm / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D018122:B7-1 Antigen / Q000235:genetics* / Q000276:immunology; D016026:Bone Marrow Transplantation; D002461:Cell Line, Transformed; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D004854:Herpesvirus 4, Human; D015395:Histocompatibility Antigens Class I / Q000032:analysis; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D015847:Interleukin-4 / Q000494:pharmacology; D015470:Leukemia, Myeloid, Acute / Q000276:immunology* / Q000378:metabolism; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D013601:T-Lymphocytes / Q000276:immunology*; D014162:Transfection; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000951:Antigens, Neoplasm; D018122:B7-1 Antigen; D015395:Histocompatibility Antigens Class I; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor