Search results for "Positive"
showing 10 items of 1875 documents
Dominant TCRB-V-J chain usage and clonal expansion of sarcoma-reactive CD4+ HLA-DR-restricted T cells suggest a limited set of immunodominant sarcoma…
1997
Tumor-reactive CD4+ T cells have been isolated from tumor patients, and their specifity but not T-cell receptor (TCR) repertoire has been analyzed. Since we have described CD4+ sarcoma-reactive T-cell clones, we now sought to determine whether the TCR repertoire of these clones provides information on the spectrum of recognized sarcoma antigens. We analyzed the TCR beta (TCRB) chain repertoire of 19 CD4+ HLA-DR-restricted T-cell clones reactive with the autologous sarcoma cell line MZ-MES-1, with HLA-DR-matched tumor cell lines of different tissue origins and B-cell blasts. We identified 7 different clonotypes, which used a limited set of TCRBV and TCRBJ segments. Although the CDR3 of the d…
The gp130-stimulating designer cytokine hyper-IL-6 promotes the expansion of human hematopoietic progenitor cells capable to differentiate into funct…
2000
Abstract Objective . Hyper-IL-6, a fusion protein of interleukin-6 and its specific receptor, together with stem cell factor leads to the proliferation of primitive hematopoietic progenitor cells. Based on these findings, the current study examined whether hyper-IL-6 promotes the growth of precursor cells that can be further differentiated into dendritic cells in the presence of additional cytokines. Methods . Dendritic cell cultures were generated from CD34 + hematopoietic progenitor cells derived either from bone marrow or from peripheral blood. CD34 + cells were cultured in the presence of cytokines for 2 weeks and then used for phenotyping and T-cell stimulation assays. Results . Hyper-…
Th9 Cells: A Novel CD4 T-cell Subset in the Immune War against Cancer
2015
Abstract CD4 T cells are key components of the immune system that shape the anticancer immune response in animal models and in humans. The biology of CD4 T cells is complex because naïve T cells can differentiate into various subpopulations with various functions. Recently, a new population called Th9 cells was described. These cells are characterized by their ability to produce IL9 and IL21. They were first described in the context of parasite infections and allergic processes. However, some reports described their presence in the tumor bed in mice and humans. Their high secretion of IL9 and IL21 in the tumor bed contributes to their anticancer functions. Indeed, these cytokines trigger th…
Reduced numbers of IL-7 receptor (CD127) expressing immune cells and IL-7-signaling defects in peripheral blood from patients with breast cancer
2007
Interleukin-7-receptor-signaling plays a pivotal role in T-cell development and maintenance of T-cell memory. We studied IL-7Ralpha (CD127) expression in PBMCs obtained from patients with breast cancer and examined IL-7 receptor-mediated downstream effects defined by STAT5 phosphorylation (p-STAT5). Reduced numbers of IL-7Ralpha-positive cells were identified in CD4+ T-cells as well as in a CD8+ T-cell subset defined by CD8alpha/alpha homodimer expression in patients with breast cancer. PBMCs obtained from healthy donors (n = 19) and from patients with breast cancer (n = 19) exhibited constitutive p-STAT5 expression in the range of 0-6.4% in CD4+ T-cells and 0-4% in CD8+ T-cells. Stimulatio…
A comparison of two types of dendritic cell as adjuvants for the induction of melanoma-specific T-cell responses in humans following intranodal injec…
2001
Dendritic cells (DCs) elicit potent anti-tumoral T-cell responses in vitro and in vivo. However, different types of DC have yet to be compared for their capacity to induce anti-tumor responses in vivo at different developmental stages. Herein, we correlated the efficiencies of different types of monocyte-derived DC as vaccines on the resulting anti-tumor immune responses in vivo. Immature and mature DCs were separately pulsed with a peptide derived from tyrosinase, MelanA/MART-1 or MAGE-1 and a recall antigen. Both DC populations were injected every 2 weeks in different lymph nodes of the same patient. Immune responses were monitored before, during and after vaccination. Mature DCs induced …
Measurement of T Cell Activation After 16‐hr In Vitro Stimulation with Concanavalin A
2010
A flow cytometry assay that can be used to directly determine the proportion of activated T lymphocytes in human whole blood samples after stimulation with concanavalin A is presented here. Human whole blood is incubated with fluorescently labeled antibodies (against CD3, CD4, CD8, and CD69), erythrocytes are then lysed, and the samples are analyzed using a flow cytometer. The assay presented is able to differentiate between CD4+ and CD8+ T lymphocytes. Thus, it is possible to quantify both lymphocyte populations in parallel, as well as the respective proportions of activated T lymphocytes, all from one sample. An additional advantage of this assay is that it was developed to assay whole bl…
Induction of cytokine production in naive CD4+ T cells by antigen-presenting murine liver sinusoidal endothelial cells but failure to induce differen…
1999
Abstract Background & Aims: Murine liver sinusoidal endothelial cells (LSECs) constitutively express accessory molecules and can present antigen to memory Th1 CD4+ T cells. Using a T-cell receptor transgenic mouse line, we addressed the question whether LSECs can prime naive CD4+ T cells. Methods: Purified LSECs were investigated for their ability to induce activation and differentiation of naive CD4+ T cells in comparison with bone marrow–derived antigen-presenting cells and macrovascular endothelial cells. Activation of T cells was determined by cytokine production. LSECs were further studied for expression of interleukin (IL)-12 by reverse-transcription polymerase chain reaction, and the…
Soluble GARP has potent antiinflammatory and immunomodulatory impact on human CD4+ T cells
2013
Glycoprotein A repetitions predominant (GARP) is expressed on the surface of activated human regulatory T cells (Treg) and regulates the bioavailability of transforming growth factor-β (TGF-β). GARP has been assumed to require membrane anchoring. To investigate the function of GARP in more detail, we generated a soluble GARP protein (sGARP) and analyzed its impact on differentiation and activation of human CD4⁺ T cells. We demonstrate that sGARP efficiently represses proliferation and differentiation of naïve CD4⁺ T cells into T effector cells. Exposure to sGARP induces Foxp3, decreases proliferation and represses interleukin (IL)-2 and interferon-γ production, resulting in differentiation …
Assessment of local cellular immunity in lung cancer by bronchoalveolar lavage.
1990
Small cell lung cancer (SCLC) is the most malignant of the pulmonary neoplasms and is associated with a poor local cellular immune response. 16 patients with non small cell lung cancer (NSCLC) and 11 patients with SCLC underwent bronchoalveolar lavage (BAL) in the lung which harbored the tumor in order to investigate the lymphocyte surface antigens utilizing the immunoperoxidase technique. Analysis of blood lymphocytes was performed in parallel. 8 patients with previous sarcoidosis in complete remission who underwent BAL and 10 normal blood donors served as controls. Among blood lymphocytes the CD3+, CD4+ and CD16+ cell populations were elevated significantly and the T4/T8 ratio was elevate…
Timing of activation of CD4+ memory cells as a possible marker to establish the efficacy of vaccines against contagious agalactia in sheep
2013
Mycoplasma agalactiae is a major pathogen of sheep and goats in many areas of the world and particularly in Mediterranean countries. It causes contagious agalactia, an infectious disease primarily affecting mammary glands. Many vaccines against the pathogen are currently under development. The aim of the study was to investigate the involvement of T cell-mediated immunity during vaccination and challenge experiments against Mycoplasma agalactiae. A comparison of the antigen-specific expansion of interferon gamma positive T cell memory and naïve subsets was performed between vaccinated and non-vaccinated sheep to identify cellular subsets whose activation was different between protected and …