a-chromatin-immunoprecipitation-assay-to-identify-novel-nfat2-target

A Chromatin Immunoprecipitation Assay to Identify Novel NFAT2 Target Genes in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is characterized by the expansion of malignant B cell clones and represents the most common leukemia in western ...

University of Tübingen

We analyzed the role of CD8+ T cells on dendritic cells (DCs). Incubation of monocytes with activated but not resting CD8+ T cells induced their differentiation into DCs with a CD1a+ and CD14- phenotype. Activated CD8+ lymphocytes induced down-regulation of CD14 expression in interleukin (IL)-10-treated macrophages and resulted in the expression of DC-related CD1a and up-regulation of mRNA transcripts for RelB, IL-12p40, MCP-2, MIP-1alpha, and ELC. These DCs were potent stimulatory cells in mixed lymphocyte reaction and induced primary CTL responses. This interaction was independent of a direct cell-to-cell contact. Monoclonal antibodies against IFN-gamma completely abolished the CD1a induction on IL-10-treated antigen-presenting cells. These results demonstrate that CD8+ cells can provide stimulatory signals to antigen-presenting cells to induce their differentiation in DC and to increase their immunostimulatory capacity.

Activated CD8+ T lymphocytes induce differentiation of monocytes to dendritic cells and restore the stimulatory capacity of interleukin 10-treated antigen-presenting cells.

A phase I trial was conducted to evaluate the feasibility, safety, and efficacy of a dendritic cell-based vaccination in patients with metastatic renal cell carcinoma (RCC). Autologous mature dendritic cells derived from peripheral blood monocytes were pulsed with the HLA-A2-binding MUC1 peptides (M1.1 and M1.2). For the activation of CD4(+) T-helper lymphocytes, dendritic cells were further incubated with the PAN-DR-binding peptide PADRE. Dendritic cell vaccinations were done s.c. every 2 weeks for four times and repeated monthly until tumor progression. After five dendritic cell injections, patients additionally received three injections weekly of low-dose interleukin-2 (1 million IE/m(2)). The induction of vaccine-induced T-cell responses was monitored using enzyme-linked immunospot and Cr release assays. Twenty patients were included. The treatment was well tolerated with no severe side effects. In six patients, regression of the metastatic sites was induced after vaccinations with three patients achieving an objective response (one complete response, two partial responses, two mixed responses, and one stable disease). Additional four patients were stable during the treatment for up to 14 months. MUC1 peptide-specific T-cell responses in vivo were detected in the peripheral blood mononuclear cells of the six patients with objective responses. Interestingly, in patients responding to the treatment, T-cell responses to antigens not used for vaccinations, such as adipophilin, telomerase, or oncofetal antigen, could be detected, indicating that epitope spreading might occur. This study shows that MUC1 peptide-pulsed dendritic cells can induce clinical and immunologic responses in patients with metastatic RCC.

Immunologic and clinical responses after vaccinations with peptide-pulsed dendritic cells in metastatic renal cancer patients.

To determine the long-term outcome of patients after allogeneic transplantation of T-cell depleted versus unmanipulated hematopoietic stem cell grafts with respect to incidence of GvHD and overall survival in 50 consecutive patients.

Long-term results after transplantation of CD34+ selected (CellPro) versus unselected peripheral blood progenitor cells (PBPC) from related allogeneic donors.

More than two years after unrelated stem cell transplantation with ongoing immunosuppressive therapy due to chronic graft-versus-host disease a patient was admitted with dyspnea. In the sequel, the patient developed ptosis.

[Invasive sinusitis after allogenic stem cell transplantation - Case 4/2010].

According to experimental animal models and experiences of patients with coexisting autoimmune diseases, allogeneic stem cell transplantation has the potential to reestablish and maintain immunological tolerance. On the other hand, it is associated with significant treatment related mortality and may induce diverse immunological diseases by graft-versus-host reaction. Other than with severe aplastic anemia, it is not an established therapy for autoimmune diseases; it is under investigation in clinical trials and might be considered in severe, refractory immune cytopenia.

[Allogeneic stem cell transplantation : An option for autoimmune diseases?]

Chronic lymphocytic leukaemia (CLL) is a clonal disorder of mature B cells. Most patients are characterised by an indolent disease course and an anergic phenotype of their leukaemia cells, which refers to a state of unresponsiveness to B cell receptor stimulation. Up to 10% of CLL patients transform from an indolent subtype to an aggressive form of B cell lymphoma over time (Richter´s syndrome) and show a significantly worse treatment outcome. Here we show that B cell-specific ablation of Nfat2 leads to the loss of the anergic phenotype culminating in a significantly compromised life expectancy and transformation to aggressive disease. We further define a gene expression signature of anergic CLL cells consisting of several NFAT2-dependent genes including Cbl-b, Grail, Egr2 and Lck. In summary, this study identifies NFAT2 as a crucial regulator of the anergic phenotype in CLL.NFAT2 is a transcription factor that has been linked with chronic lymphocytic leukaemia (CLL), but its functions in CLL manifestation are still unclear. Here the authors show, by analysing mouse CLL models and characterising biopsies from CLL patients, that NFAT2 is an important regulator for the anergic phenotype of CLL.

Stefan Wirths

Dept. of Hematology,
Oncology and Immunology,
Dept. of Hematology, Oncology and Immunology

University of Tübingen

A Chromatin Immunoprecipitation Assay to Identify Novel NFAT2 Target Genes in Chronic Lymphocytic Leukemia

Stefan Wirths

Dept. of Hematology,Oncology and Immunology,Dept. of Hematology, Oncology and Immunology

University of Tübingen

A Chromatin Immunoprecipitation Assay to Identify Novel NFAT2 Target Genes in Chronic Lymphocytic Leukemia

Dept. of Hematology,
Oncology and Immunology,
Dept. of Hematology, Oncology and Immunology