Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Successful stem cell transplantation (SCT) across HLA barriers can be performed with cord blood, megadoses of stem cells, or with nonmyeloablative conditioning strategies. Because the HLA-mismatched transplants are often T-cell depleted, leukemia relapse rates are high. Treatment of relapsed leukemia after HLA-mismatched SCT is difficult. A novel potential strategy to treat relapsed leukemia after HLA-mismatched SCT is the use of patients' mismatched HLA molecules as antigen-presenting molecules to generate hematopoietic system-specific cytotoxic T cells (CTLs) from the stem cell donor. Adoptive transfer of these hematopoietic system-specific CTLs that are restricted by nonself HLA molecules may eliminate leukemia without affecting the patient's nonhematopoietic cells or donor hematopoietic cells. We investigated the feasibility of this strategy using the hematopoietic system-specific minor histocompatibility antigen HA-1, which is known to induce HLA-A2-restricted CTLs. HLA-A2(-) peripheral blood mononuclear cells were stimulated with HLA-A2(+) T2 cells pulsed with synthetic HA-1 peptide or with dendritic cells transduced with the HA-1 cDNA. Tetrameric HLA-A2/HA-1 peptide complexes were used to monitor and enrich HA-1-specific CTLs. In the alloreactive cultures, HA-1-specific CTLs were enriched up to 7% by 3 rounds of antigen-specific stimulations and up to 87% by fluorescence-activated cell sorting of tetramer-positive T cells. The HA-1-specific CTLs showed specific lysis of the relevant target cells, including leukemic cells. Because the polyclonal CTL cultures also contained natural killer cells and allo-HLA-A2-specific CTLs, CTL clones were generated that showed the expected HA-1 specificity only. Thus, HA-1-specific CTLs restricted by nonself HLA-A2 molecules can be generated in an HLA-A2-mismatched setting.
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PMID:Generation of minor histocompatibility antigen HA-1-specific cytotoxic T cells restricted by nonself HLA molecules: a potential strategy to treat relapsed leukemia after HLA-mismatched stem cell transplantation. 1209 47

Minor histocompatibility antigens can induce cytotoxic T cells that play an important role in the graft-versus-leukemia and graft-versus-host-disease (GvHD) activity after stem cell transplantation. Minor histocompatibility antigens (mHags) with expression limited to the hematopoietic system may have a prominent role in the graft-versus-leukemia reaction. Earlier in vitro studies demonstrated that cytotoxic T cells specific for the minor histocompatibility antigen HA-1 only lysed cells of hematopoietic origin. Despite this limited expression, an HA-1 mismatch is associated with GvHD. Yet, the hematopoietic-restricted HA-1 membrane expression motivated us to develop an ex vivo HA-1-specific protocol for cellular immunotherapy of relapsed leukemia. To ensure the feasibility and safety of such cellular therapy, broad HA-1 RNA analysis is indispensable. Here we demonstrate the hematopoietic-restricted expression at the HA-1 gene transcriptional level with high RNA expression in normal and in malignant hematopoietic cells and background expression levels in nonhematopoietic cells. In tissues that showed low HA-1 RNA expression, hematopoietic cells were present as demonstrated by CD45 RNA expression analyzed in parallel. Thus, the mHag HA-1 can function as an excellent target antigen for immunotherapy of hematological malignancies with no or low risk of GvHD.
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PMID:Quantification of the HA-1 gene product at the RNA level; relevance for immunotherapy of hematological malignancies. 1450 55

Induction of cytotoxic T lymphocytes (CTLs) for treatment of relapsed leukemia after allogeneic stem-cell transplantation is hindered by the laborious and time-consuming procedure of generating dendritic cells for antigen presentation. Artificial antigen-presenting cells (aAPCs) offer the advantage of being readily available in sufficient numbers, thus allowing for a highly standardized in vitro induction of CTLs. We generated aAPCs coated with anti-CD28 antibody (Ab) and either high-density (HD) or low-density (LD) major histocompatibility complex (MHC) class I molecules loaded with HA-1(H), a nonapeptide derived from the hematopoiesis-restricted minor histocompatibility antigen HA-1. HD- and LD-aAPCs potently induced HA-1(H)-specific CD8+ CTLs from untouched CD8+ T cells of healthy donors. CTLs were subsequently purified by magnetic-activated cell sorting. HD- as well as LD-aAPC-induced CTLs exerted high HA-1H-specific cytotoxicity, resembled T(c)1 effector memory cells, survived a long time in vitro, and were expanded by a factor varying between 8.2 x 10(4) and 51 x 10(4). The T-cell receptor (TCR) repertoire of HA-1H tetramer-positive CTLs was oligoclonal with a prominent usage of Vbeta6. The TCR repertoire of tetramer-positive CTLs was distinct from and more restricted than that of tetramer-negative cells. These findings indicate that aAPCs are attractive tools for the ex vivo generation of HA-1H-specific CTLs suitable for immunotherapy of relapsed leukemia.
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PMID:Cytotoxic minor histocompatibility antigen HA-1-specific CD8+ effector memory T cells: artificial APCs pave the way for clinical application by potent primary in vitro induction. 1573 Nov 81

The purpose of this study was to construct a HA-1-DC nucleic acid vaccine and to induce anti-leukemia effect after hematopoietic stem cell transplantation (HSCT). The dendritic cells (DCs) were generated from HSCT donors in vitro, and its immunologic activity was studied by using flow cytometry and mix lymphocyte reaction. HA-1 gene was electroporated into the cultured DCs to construct a DC nucleic acid vaccine. After transfecting for 48 hours, the expression of HA-1 protein was detected by Western blot. The DCs were cultured with isogenic lymphocytes to induce specific cytotoxic T lymphocytes (CTLs). The cytotoxicity of the CTLs was detected by LDH assay. The results showed that the DCs derived from peripheral blood monocytes (PBMCs) expressed the DC phenotype, and were effective in stimulating proliferation of the allogenic lymphocytes. After electroporating for 48 hours, HA-1 protein was detected by Western blot. The cytotoxity of inducing CTLs was higher than that in the control group. It is concluded that the minor histocompatibility antigen HA-1 can be considered as a target of immunotherapy against leukemia after HSCT.
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PMID:[Construction of HA-1-DC nucleic-acid vaccine and induction of specific cytotoxic T lymphocytes]. 1720 89

An HA-1-DC nucleic-acid vaccine was constructed to induce anti-leukemia effect after hematopoietic stem cell transplantation (HSCT). DCs were generated from HSCT donors in vitro, and its immunologic activity was assayed by using flow cytometry and mixed lymphocytes reaction. HA-1 gene was electroporated into the cultured DCs to construct a DC nucleic-acid vaccine. After transfection for 48 h, the expression of HA-1 protein could be detected by using Western blot. The DCs were cultured with syngenic lymphocytes to induce specific cytotoxic T lymphocytes (CTLs). The cytoxicity of the CTLs was detected by LDH assay. The results showed that The DCs derived from peripheral blood monocytes (PBMCs) expressed the phenotype of DCs, and were effective in stimulating proliferation of the allogenic lymphocytes. After electroporating for 48-h, HA-1 protein was detected by using Western blot. The cytotoxicty of inducing CTLs was higher than the control group. It was suggested that minor histocompatibility antigen HA-1 could be considered as a target of immunotherapy against leukemia after HSCT.
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PMID:Construction of HA-1-DC nucleic-acid vaccine and induction of specific cytotoxic T lymphocytes. 1764 37

A sequential, two-step procedure in which T-cell-depleted allogeneic stem cell transplantation is followed by treatment with donor lymphocyte infusion at 6 months can significantly reduce the risk and severity of graft-versus-host disease, with postponed induction of the beneficial graft-versus-leukemia effect. However, patients with high-risk leukemia have a substantial risk of relapse early after transplantation, at a time when administration of donor lymphocytes has a high likelihood of resulting in graft-versus-host disease, disturbing a favorable balance between the graft-versus-leukemia effect and graft-versus-host disease. New therapeutic modalities are, therefore, required to allow early administration of T cells capable of exerting a graft-versus-leukemia effect without causing graft-versus-host disease. Here we describe the isolation of virus-specific T cells using Streptamer-based isolation technology and subsequent transfer of the minor histocompatibility antigen HA-1-specific T-cell receptor using retroviral vectors. Isolation of virus-specific T cells and subsequent transduction with HA-1-T-cell receptor resulted in rapid in vitro generation of highly pure, dual-specific T cells with potent anti-leukemic reactivity. Due to the short production procedure of only 10-14 days and the defined specificity of the T cells, administration of virus-specific T cells transduced with the HA-1-T-cell receptor as early as 8 weeks after allogeneic stem cell transplantation is feasible. (This clinical trial is registered at www.clinicaltrialsregister.eu as EudraCT number 2010-024625-20).
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PMID:A Good Manufacturing Practice procedure to engineer donor virus-specific T cells into potent anti-leukemic effector cells. 2433 96