Search results for "Granzyme"
showing 10 items of 32 documents
PD-1, PD-L1 and PD-L2 Gene Expression on T-Cells and Natural Killer Cells Declines in Conjunction with a Reduction in PD-1 Protein during the Intensi…
2015
Background The PD-1 axis is a cell intrinsic immunoregulatory pathway that mediates T cell exhaustion in chronic infection particularly in some viral infections. We hypothesized that PD-1, PD-L1 and PD-L2 would be highly expressed in untreated tuberculosis patients compared to controls due to their chronic infection and would decrease with successful TB treatment. Materials and Methods Untreated tuberculosis patients (n = 26) were recruited at diagnosis and followed up during treatment. Household contacts (n = 24) were recruited to establish baseline differences. Blood gene expression ex vivo was investigated using qRT-PCR. Flow cytometry was performed to establish protein expression patter…
Granzyme A as a potential biomarker of Mycobacterium tuberculosis infection and disease
2015
Cytotoxic molecules such as granulysin, perforin and granzymes produced by cytolytic T cells directly contribute to immune defense against tuberculosis (TB). In search for novel TB biomarkers, we have evaluated the levels of granzyme A in plasma obtained from QuantiFERON-TB Gold In tube (QFT-IT) assays from patients with active TB disease and subjects with latent TB infection (LTBI).Granzyme A serum levels in TB patients were significantly lower than values found in LTBI subjects even after subtraction of the unstimulated levels from the antigen-stimulated responses. The receiver operator characteristics (ROC) curve analysis comparing TB patients and LTBI groups, showed that at a cut-off va…
Differentiation, phenotype, and function of interleukin-17-producing human Vγ9Vδ2 T cells.
2011
Abstract In healthy adults, the major peripheral blood γδ T-cell subset expresses the Vγ9Vδ2 TCR and displays pleiotropic features. Here we report that coculture of naive Vγ9Vδ2 T cells with phosphoantigens and a cocktail of cytokines (IL-1-β, TGF-β, IL-6, and IL-23), leads to selective expression of the transcription factor RORγt and polarization toward IL-17 production. IL-17+ Vγ9Vδ2 T cells express the chemokine receptor CCR6 and produce IL-17 but neither IL-22 nor IFN-γ; they have a predominant terminally differentiated (CD27−CD45RA+) phenotype and express granzyme B, TRAIL, FasL, and CD161. On antigen activation, IL-17+ Vγ9Vδ2 T cells rapidly induce CXCL8-mediated migration and phagocy…
Long-term freedom from recurrence in 2 stage IV melanoma patients following vaccination with tyrosinase peptides.
2002
We report here on 2 patients who received adjuvant vaccination with an HLA-A2- or HLA-A24-restricted tyrosinase peptide, respectively, and GM-CSF for frequently relapsing stage IV melanoma. Following resection of metastases and irradiation of brain metastases in 1 patient, both patients were without evidence of disease when receiving the first vaccination. While the patients had had 9 and 12, respectively, mostly s.c., relapses during the 3 years before vaccination, they experienced freedom from relapse for more than 2 years after vaccination. We found a T-cell response to the vaccine peptide in both patients in the peripheral blood by ex vivo IFN-gamma ELISPOT assay. The T-cell population …
Abstract 4740: Doxorubicin eliminates tumor-induced myeloid-derived suppressor cells and enhances T-helper lymphocyte-based immunotherapy in a murine…
2013
Abstract Myeloid-derived suppressor cells (MDSC) represent a heterogeneous population of cells equipped with the ability to inhibit T lymphocyte-mediated immune responses. A significant increase in the number of MDSC has been reported in the blood, secondary lymphoid organs and tumor beds in tumor-bearing animals and in patients with many types of cancers. MDSC frequency correlates with the disease stage and prognosis. These cells impair CD8+ cytotoxic T lymphocyte (CTL)-mediated anti-tumor immunity by different overlapping mechanisms such as reactive oxygen species or immunosuppressive cytokine production. Importantly, MDSC elimination or inactivation substantially enhances the efficiency …
Invariant natural killer T cells act as an extravascular cytotoxic barrier for joint-invading Lyme Borrelia
2014
CXCR6-GFP(+) cells, which encompass 70% invariant natural killer T cells (iNKT cells), have been found primarily patrolling inside blood vessels in the liver. Although the iNKT cells fail to interact with live pathogens, they do respond to bacterial glycolipids presented by CD1d on liver macrophage that have caught the microbe. In contrast, in this study using dual laser multichannel spinning-disk intravital microscopy of joints, the CXCR6-GFP, which also made up 60-70% iNKT cells, were not found in the vasculature but rather closely apposed to and surrounding the outside of blood vessels, and to a lesser extent throughout the extravascular space. These iNKT cells also differed in behavior,…
Dendritic cells trigger tumor cell death by a nitric oxide-dependent mechanism.
2007
Abstract Dendritic cells (DCs) are well known for their capacity to induce adaptive antitumor immune response through Ag presentation and tumor-specific T cell activation. Recent findings reveal that besides this role, DCs may display additional antitumor effects. In this study, we provide evidence that LPS- or IFN-γ-activated rat bone marrow-derived dendritic cells (BMDCs) display killing properties against tumor cells. These cytotoxic BMDCs exhibit a mature DC phenotype, produce high amounts of IL-12, IL-6, and TNF-α, and retain their phagocytic properties. BMDC-mediated tumor cell killing requires cell-cell contact and depends on NO production, but not on perforin/granzyme or on death re…
An Ovalbumin Peptide-Specific Cytotoxic T Cell Clone with Antigen Self-Presentation Capacity Uses Two Distinct Mechanisms to Kill Target Cells
1993
Abstract Cloned 10BK.1 T cells with specificity for the ovalbumin peptide OVA257-264 are representative of a novel cell type within the CD8 + subset of T cells. In the presence and in the absence of added antigen presenting cells these T cells react toward antigen (Ag) by proliferation and lymphokine production. These data suggest self-presentation of the Ag by 10BK.1 cells. Here we present evidence that 10BK.1 cells exhibit cytotoxic activity that involves two different cytotoxic effector mechanisms. (i) One mechanism is fast killing activity, apparent within 4 hr. Constitutive mouse T cell-specific proteinase-1 (MTSP-1) activity, constitutive expression of MTSP-1 RNA, increased by Ag chal…
Cytotoxicity of tumor antigen specific human T cells is unimpaired by arginine depletion.
2013
Tumor-growth is often associated with the expansion of myeloid derived suppressor cells that lead to local or systemic arginine depletion via the enzyme arginase. It is generally assumed that this arginine deficiency induces a global shut-down of T cell activation with ensuing tumor immune escape. While the impact of arginine depletion on polyclonal T cell proliferation and cytokine secretion is well documented, its influence on chemotaxis, cytotoxicity and antigen specific activation of human T cells has not been demonstrated so far. We show here that chemotaxis and early calcium signaling of human T cells are unimpaired in the absence of arginine. We then analyzed CD8(+) T cell activation…
Delivery and therapeutic potential of human granzyme B
2010
Summary: Granzyme B (GzmB) is used by cytotoxic lymphocytes as a molecular weapon for the defense against virus-infected and malignantly transformed host cells. It belongs to a family of small serine proteases that are stored in secretory vesicles of killer cells. After secretion of these cytolytic granules during killer cell attack, GzmB is translocated into the cytosol of target cells with the help of the pore-forming protein perforin. GzmB has adopted similar protease specificity as caspase-8, and once delivered, it activates major executioner apoptosis pathways. Since GzmB is very effective in killing human tumor cell lines that are otherwise resistant against many cytotoxic drugs and …