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Granzyme B Produced by Natural Killer Cells Enhances Inflammatory Response and Contributes to the Immunopathology of Cutaneous Leishmaniasis.

BACKGROUND: Skin lesions from patients infected with Leishmania braziliensis has been associated with inflammation induced by cytotoxic CD8+ … bjects, and that NK cells expressed more interferon-γ, tumor necrosis factor (TNF), granzyme B, and perforin than CD8+ T cells. RESULTS: We also found that most of the cytotoxic activity in CL lesions was triggered by NK cells, and that the high levels of granzyme B produced in CL lesions was associated with larger lesion size. Furthermore, an in vitro bl …

SerpinB1 controls encephalitogenic T helper cells in neuroinflammation.

SerpinB1, a protease inhibitor and neutrophil survival factor, was recently linked with IL-17-expressing T cells. Here, we show that serpinB1 (Sb1) is dramatically induced in a subset of effector CD4 cells in experimental autoimmune encephalomyelitis (EAE). Despite normal T cell priming, Sb1-/- mice are resistant to EAE with a paucity of T helper (TH) cells that produce two or more of the cytokines, IFNγ, GM-CSF, and IL-17. These multiple cytokine-producing CD4 cells proliferate extremely rapidly; highly express the cytolytic granule proteins perforin-A, granzyme C (GzmC), and GzmA and surface…

MAIT cells protect against pulmonary Legionella longbeachae infection.

Mucosal associated invariant T (MAIT) cells recognise conserved microbial metabolites from riboflavin synthesis. Striking evolutionary conse … thal Legionella infection. Protection is dependent on MR1, IFN-γ and GM-CSF, but not IL-17A, TNF or perforin, and enhanced protection is detected earlier after infection of mice antigen-primed to boost MAIT cell numbers before infection. Our findings define a function for MAIT cells in protection against a major human pathogen and indicate a potential role …

Weak vaccinia virus-induced NK cell regulation of CD4 T cells is associated with reduced NK cell differentiation and cytolytic activity.

Natural killer (NK) cells control antiviral adaptive immune responses in mice during some virus infections, but the universality of this phe … phenotype, and lower expression levels of the activation marker CD69, cytotoxic effector molecules (perforin, granzyme B), and the transcription factor IRF4. NKVACV cells expressed higher levels of the inhibitory molecule NKG2A than NKLCMV cells. Consistent with this apparent lethargy, NKVACV cells only weakly constrained VACV-specific CD4 T-cell responses …

TGF-β1 improving abnormal pregnancy outcomes induced by Toxoplasma gondii infection: Regulating NKG2D/DAP10 and killer subset of decidual NK cells.

Our current aim was to investigate whether injection of TGF-β1 played an important role in improving abnormal pregnancy outcomes with T. gondii infection and how the TGF-β1 regulated. Results showed that TGF-β1 exhibited improved pregnancy outcomes induced by T. gondii infection. dNK cytotoxicity was increased with T. gondii infection while decreased with TGF-β1 treatment. dNK cytotoxicity related NKG2D/DAP10 expression, perforin, granzyme, IFN-γ and killer subsets were all increased with T. gondii infection while decreased after TGF-β1 treatment. In addition, anti-TGF-β1 antibodies could aggr…

Mixed signature of activation and dysfunction allows human decidual CD8+ T cells to provide both tolerance and immunity.

Understanding how decidual CD8+ T cell (CD8+ dT) cytotoxicity is regulated and how these cells integrate the competing needs for maternal-fe … olerance to fetal antigens. However, CD8+ dT degranulated, proliferated, and produced IFN-γ, TNF-α, perforin, and granzymes upon in vitro stimulation, demonstrating that CD8+ dT are not permanently suppressed and retain the capacity to respond to proinflammatory events, such as infections. The balance between transient dysfunction of CD8+ dT that are permi …

Granzyme K-deficient mice show no evidence of impaired antiviral immunity.

The biological role of granzyme K, a serine protease of cytotoxic T lymphocytes (CTL), is controversial. It has been reported to induce perforin-mediated cell death in vitro, but is also reported to be non-cytotoxic and to operate in inflammatory processes. To elucidate the biological role of this protease, we have deleted the granzyme K gene in mice (mutant allele: Gzmktm1.1Pib; MGI:5636646). Gzmk -/- mice are healthy, anatomically normal, fecund and show normal hematopoietic development. Gzmk -/- mice readily recover from lymphocytic choriomeningitis virus and mouse pox Ectromelia virus infe…

Blinatumomab for the treatment of adult acute lymphoblastic leukemia.

The marker CD19 is frequently expressed on the surface of malignant B cells including non-Hodgkin's lymphoma (NHL), chronic lymphocytic leuk … mains. Once bound to both the T and B cell, blinatumomab induces T-cell activation and subsequently perforin-mediated malignant B-cell death. It has shown efficacy in ALL with minimal residual disease, relapsed/refractory ALL, and NHL in phase I and II clinical trials. With a favorable safely profile and promising results, blinatumomab was granted accelera …

Dengue virus infection elicits highly polarized CX3CR1+ cytotoxic CD4+ T cells associated with protective immunity.

Dengue virus (DENV) is a rapidly spreading pathogen with unusual pathogenesis, and correlates of protection from severe dengue disease and v … e virus-specific cells were highly polarized, with a strong bias toward a CX3CR1(+) Eomesodermin(+) perforin(+) granzyme B(+) CD45RA(+) CD4 CTL phenotype. Importantly, these cells correlated with a protective HLA DR allele, and we demonstrate that these cells have direct ex vivo DENV-specific cytolytic activity. We speculate that cytotoxic dengue-specific …

Natural Killer Cell Functional Activity After 4-1BB Costimulation.

Reports show enhancement of CD8 T cells' activity through CD137 (4-1BB) signal; however, not all data proved similar effect in natural kille … ther enhanced cellular degranulation nor improved IFN-γ production although it promoted granzyme B, perforin, and FasL gene expression. 4-1BB signal stimulated higher proportions of CD56bright population to degranulate and express CD107a; however, it could not recover killing activity against K562 targets. Our data could not show major promotion in activit …

Generation of cellular immune memory and B-cell immunity is impaired by natural killer cells.

The goal of most vaccines is the induction of long-lived memory T and B cells capable of protecting the host from infection by cytotoxic mec … ection. Mechanistically, NK cells suppressed CD4 T cells and follicular helper T cells (T(FH)) in a perforin-dependent manner during the first few days of infection, resulting in a weaker germinal centre (GC) response and diminished immune memory. We anticipate that innovative strategies to relieve NK cell-mediated suppression of immunity should facilitate …

Human γδ thymocytes are functionally immature and differentiate into cytotoxic type 1 effector T cells upon IL-2/IL-15 signaling.

Cytotoxicity and IFN-γ production by human γδ T cells underlie their potent antitumor functions. However, it remains unclear where and how h … ovo expression of the transcription factors T-bet and eomesodermin, as well as the cytolytic enzyme perforin, required for the cytotoxic type 1 program. These findings have implications for the manipulation of γδ T cells in cancer immunotherapy.

Elucidating sources and roles of granzymes A and B during bacterial infection and sepsis.

During bacterial sepsis, proinflammatory cytokines contribute to multiorgan failure and death in a process regulated in part by cytolytic cell granzymes. When challenged with a sublethal dose of the identified mouse pathogen Brucella microti, wild-type (WT) and granzyme A (gzmA)(-/-) mice eliminate the organism from liver and spleen in 2 or 3 weeks, whereas the bacteria persist in mice lacking perforin or granzyme B as well as in mice depleted of Tc cells. In comparison, after a fatal challenge, only gzmA(-/-) mice exhibit increased survival, which correlated with reduced proinflammatory cytok…

Polymyositis in solid organ transplant recipients receiving tacrolimus.

Tacrolimus, also known as FK506, is an immunosuppressive agent widely used for the prevention of acute allograft rejection in organ transpla … olymyositis including CD8+ T cells which invaded healthy muscle fibers and expressed granzyme B and perforin, many CD68+ macrophages and MHC class I antigen upregulation on the surface of most fibers. Because of the temporal association while receiving tacrolimus and since other possible causes for myopathy were excluded, the most likely cause of polymyosi …

Memory CD4+ T cells protect against influenza through multiple synergizing mechanisms.

Memory CD4+ T cells combat viral infection and contribute to protective immune responses through multiple mechanisms, but how these pathways … on of IFN-γ. Moreover, memory CD4+ T cells selected for epitope-specific viral escape mutants via a perforin-dependent pathway. By deconstructing protective immunity mediated by memory CD4+ T cells, we demonstrated that this population simultaneously acts through multiple pathways to provide a high level of protection that ensures eradication of rapidly mu …

Cutting edge: persistently open chromatin at effector gene loci in resting memory CD8+ T cells independent of transcriptional status.

Memory CD8(+) T cells are characterized by more rapid and robust effector function upon infection compared with naive T cells, but factors governing effector gene responsiveness are incompletely understood. We sought to understand transcriptional control of the effector genes IFN-γ (Ifng), granzyme B (Gzmb), and perforin 1 (Prf1) in murine memory CD8(+) T cells by characterizing their transcriptional profiles and chromatin states during lymphocytic choriomeningitis virus infection. Each effector gene has a distinct transcriptional profile in resting memory cells and following restimulation. Pr…

Природная активация клеток-убийц усиливает иммунную патологию и поощряет хроническую инфекцию, ограничивая иммунитет CD8+T-клетки.

Инфекции ВИЧ, вирусом гепатита В и вирусом гепатита С могут превратиться в хронические инфекции, от которых в настоящее время страдают более 500 миллионов пациентов во всем мире. Как правило, считается, что вирусообразование Т-клеток ограничивает функцию Т-клеток, тем самым поощряя хронические заболевания. Здесь мы показываем, что клетки естественного убийцы (НК) оказывают негативное воздействие на развитие иммунитета Т-клеток, используя вирус муслин лимфоцита хориомингита. NK-недостаток клеток (Nfil3(-/-), E4BP4(-/-)) мыши продемонстрировали более высокую чувствительность к вирусу Т-клеток. К

Совпадение в аннотации оригинала
Infections with HIV, hepatitis B virus, and hepatitis C virus can turn into chronic infections, which currently affect more than 500 million … urther experiments showed that NKG2D triggered regulatory NK cell functions, which were mediated by perforin, and limited T-cell responses. Therefore, we identified an important role of regulatory NK cells in limiting T-cell immunity during virus infection.

Increased number of cytotoxic CD3+ CD28- gammadelta T cells in peripheral blood of patients with cutaneous malignant melanoma.

BACKGROUND: A rise of CD3+ TCRgammadelta+ CD28- T cells has previously been observed after an in vitro long-lasting activation or even durin … by an accumulation of the CD3+ TCRgammadelta+ CD28- T-cell subset, which expressed a high amount of perforin both in normal individuals and melanoma patients. CONCLUSION: This work shows, for the first time, a rise of the cytotoxic CD3+ TCRgammadelta+ CD28- T-cell population in melanoma patients, which may be important in anticancer surveillance.

Cutting edge: syntaxin 11 regulates lymphocyte-mediated secretion and cytotoxicity.

Little is known about the regulatory roles of specific soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins in cytotoxic lymphocytes. Recent information suggests that mutations in the SNARE protein syntaxin 11 result in a form of familial hemophagocytic lymphohistiocytosis (FHL). Because genetic abnormalities in key granule components (e.g., perforin) or in regulators of secretion (e.g., Munc13-4) underlie the other identified forms of FHL, we assessed whether syntaxin 11 might also serve a related regulatory role. We determined that syntaxin 11 is expressed i…

Detection of virus-specific T cells and CD8+ T-cell epitopes by acquisition of peptide-HLA-GFP complexes: analysis of T-cell phenotype and function in chronic viral infections.

Antigen-specific CD8+ T cells acquire peptide-major histocompatibility complex (MHC) clusters through T-cell receptor (TCR)-mediated endocyt … tide-HLA-GFP complexes by antigen-specific T cells could distinguish, with respect to phenotype and perforin production, T cells from the chronic viral infections cytomegalovirus and HTLV-I. This approach will be a powerful tool in understanding the role of antigen-specific T-cell responses in health and disease.