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Bone marrow transplantation (BMT) is mainly performed to restore an anti-tumor immune response, called the graft-versus-tumor (GVT) effect, against leukemia, myeloma and lymphoma. This GVT reactivity is driven by donor T cells, and it can also cause lethal graft-versus-host disease (GVHD). We previously demonstrated that the colonization of mice with helminths preserves the GVT response while suppressing GVHD. As the T helper-2 (Th2) pathway is critical to helminthic immune regulation, we asked whether the genetic induction of Th2 signaling in donor T cells can restore helminthic immune regulation after BMT. Our studies utilized transgenic donor T lymphocytes that overexpress a constitutively active form of the Th2-associated transcription factor STAT6. Constitutively active STAT6 sustained the GVT response without causing severe acute GVHD, where transgenic T cells generated robust quantities of cytotoxic proteins important in GVT response, such as granzymes A and B, interferon-γ and Fas ligand, in addition to generating high quantities of Th2/regulatory cytokines. Bioinformatic analysis based on chromosome immune precipitation experiments indicated that STAT6 stimulates the expression of granzymes directly. Thus, in preserving the GVT response without causing GVHD mortality, our results indicate the therapeutic potential of restoring helminthic immune modulation by targeting STAT6 and STAT6-dependent T cell maturation. [ABSTRACT FROM AUTHOR]

Granzyme A (GzmA) secreted by natural killer (NK) cells has garnered considerable interest as a biomarker to evaluate the efficacy of cancer immunotherapy. However, current methodologies to selectively monitor the spatial distribution of GzmA in cancer cells during NK cell‐targeted therapy are extremely challenging, primarily due to the existence of diverse cell populations, the low levels of GzmA expression, and the limited availability of GzmA probes. Herein we develop a multi‐modular, structurally‐ordered DNA nanodevice for evaluating NK cell‐mediated cancer immunotherapy (MODERN), that permits spatioselective imaging of GzmA in cancer cells through GzmA‐induced apurinic/apyrimidinic endonuclease 1 (APE1) inactivation. The MODERN incorporates multiple functional modules, including an APE1‐gated recognition module, a photo‐activated amplification module, an aptamer‐mediated tumor‐target module, and a polycatenane DNA module, enabling improved sensitivity and specificity towards intracellular GzmA. The MODERN was activated (on) in cancer cells due to the overexpression of APE1, whereas it remained silent (off) in the NK‐treated cancer cells owing to the GzmA‐induced APE1 inactivation. Furthermore, we demonstrated that GzmA‐induced APE1 inactivation blocks the cellular repair of target cells, resulting in efficient cell death. This MODERN that relies on the specific inactivation of APE1 by GzmA should be beneficial for evaluating the efficacy of cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Abstract CD8+T cells secreting granzyme A (GZMA) can induce pyroptosis in tumor cells by effectively cleaving gasdermin B (GSDMB), which is stimulated by interferon-γ (IFN-γ). However, the interaction between GZMA-expressing CD8+T cells and GSDMB-expressing tumor cells in colon cancer remains poorly understood. Our research employed multi-color immunohistochemistry (mIHC) staining and integrated clinical data to explore the spatial distribution and clinical relevance of GZMA- and IFN-γ-expressing CD8+ tumor-infiltrating lymphocytes (TILs), as well as GSDMB-expressing CK+ cells, within the tumor microenvironment (TME) of human colon cancer samples. Additionally, we utilizing single-cell RNA sequencing (scRNA-seq) data to examine the functional dynamics and interactions among these cell populations. scRNA-seq analysis of colorectal cancer (CRC) tissues revealed that CD8+TILs co-expressed GZMA and IFN-γ, but not other cell types. Our mIHC staining results indicated that a significant reduction in the infiltration of GZMA+IFN-γ+CD8+TILs in colon cancer patients (P

CD8+T cells secreting granzyme A (GZMA) can induce pyroptosis in tumor cells by effectively cleaving gasdermin B (GSDMB), which is stimulated by interferon-γ (IFN-γ). However, the interaction between GZMA-expressing CD8+T cells and GSDMB-expressing tumor cells in colon cancer remains poorly understood. Our research employed multi-color immunohistochemistry (mIHC) staining and integrated clinical data to explore the spatial distribution and clinical relevance of GZMA- and IFN-γ-expressing CD8+ tumor-infiltrating lymphocytes (TILs), as well as GSDMB-expressing CK+ cells, within the tumor microenvironment (TME) of human colon cancer samples. Additionally, we utilizing single-cell RNA sequencing (scRNA-seq) data to examine the functional dynamics and interactions among these cell populations. scRNA-seq analysis of colorectal cancer (CRC) tissues revealed that CD8+TILs co-expressed GZMA and IFN-γ, but not other cell types. Our mIHC staining results indicated that a significant reduction in the infiltration of GZMA+IFN-γ+CD8+TILs in colon cancer patients (P < 0.01). Functional analysis results indicated that GZMA+IFN-γ+CD8+TILs demonstrated enhanced activation and effector functions compared to other CD8+TIL subsets. Furthermore, GSDMB-expressing CK+ cells exhibited augmented immunogenicity. Correlation analysis highlighted a positive association between GSDMB+CK+ cells and GZMA+IFN-γ+CD8+TILs (r = 0.221, P = 0.033). Analysis of cell-cell interactions further showed that these interactions were mediated by IFN-γ and transforming growth factor-β (TGF-β), the co-stimulatory molecule ICOS, and immune checkpoint molecules TIGIT and TIM-3. These findings suggested that GZMA+IFN-γ+CD8+TILs modulating GSDMB-expressing tumor cells, significantly impacted the immune microenvironment and patients' prognosis in colon cancer. By elucidating these mechanisms, our present study aims to provide novel insights for the advancement of immunotherapeutic strategies in colon cancer. [ABSTRACT FROM AUTHOR]

Background/Objectives: Cancer remains a significant global health concern, with immunotherapies emerging as promising treatments. This study explored the role of perforin-1 (PRF1) and granzymes A, B and K (GZMA, GZMB and GZMK) in cancer biology, focusing on their impact on tumor cell death and immune response modulation. Methods: Through a comprehensive genomic analysis across various cancer types, we explored the differential expression, mutation profiles and methylation patterns of these genes, providing insights into their potential as therapeutic targets. Furthermore, we investigated their association with immune cell infiltration and pathway activation within the tumor microenvironment in each tumor type. Results: Our findings revealed distinct expression patterns and prognostic implications for PRF1, GZMA, GZMB and GZMK across different cancers, highlighting their multifaceted roles in tumor immunity. We found increased immune infiltration across all tumor types and significant correlations between the genes of interest and cytotoxic T cells, as well as the most significant survival outcomes in breast cancer. We also show that granzymes and perforin-1 are significantly associated with indicators of immunosuppression and T cell dysfunction within patient cohorts. In skin melanoma, glioblastoma, kidney and bladder cancers, we found significant correlations between the genes of interest and patient survival after receiving immune-checkpoint inhibition therapy. Additionally, we identified potential associations between the mRNA expression levels of these genes and drug sensitivity. Conclusions: Overall, this study enhances our understanding of the molecular mechanisms underlying tumor immunity and provides valuable insights into the potential therapeutic implications of PRF1, GZMA, GZMB and GZMK in cancer treatment.

Mycobacterium tuberculosis (Mtb)-specific γ9δ2 T cells secrete granzyme A (GzmA) protective against intracellular Mtb growth. However, GzmA-enzymatic activity is unnecessary for pathogen inhibition, and the mechanisms of GzmA-mediated protection remain unknown. We show that GzmA homodimerization is essential for opsonization of mycobacteria, altered uptake into human monocytes, and subsequent pathogen clearance within the phagolysosome. Although monomeric and homodimeric GzmA bind mycobacteria, only homodimers also bind cluster of differentiation 14 (CD14) and Toll-like receptor 4 (TLR4). Without access to surface-expressed CD14 and TLR4, GzmA fails to inhibit intracellular Mtb. Upregulation of Rab11FIP1 was associated with inhibitory activity. Furthermore, GzmA colocalized with and was regulated by protein disulfide isomerase AI (PDIA1), which cleaves GzmA homodimers into monomers and prevents Mtb inhibitory activity. These studies identify a previously unrecognized role for homodimeric GzmA structure in opsonization, phagocytosis, and elimination of Mtb in human monocytes, and they highlight PDIA1 as a potential host-directed therapy for prevention and treatment of tuberculosis, a major human disease. [ABSTRACT FROM AUTHOR]

Aim: T cells are key immunomodulatory cells in periapical lesions. This study aimed to explore the roles of T cells in chronic apical periodontitis (CAP) using single‐cell RNA sequencing and to further investigate Granzyme A (GZMA) in angiogenesis regulation. Methodology: A total of five CAP samples were collected for single‐cell RNA sequencing. We performed subcluster and lineage‐tracing analyses for T cells. According to differential gene expression, distinct biological functions enriched in T cells of CAP were presented by gene set enrichment analysis (GSEA) and compared with healthy gingiva (data obtained from the GEO database). CellChat was used to explore potential ligand–receptor interactions between T cells and endothelial cells in CAP. The coculture of primary human umbilical vein endothelial cells (HUVECs) and Jurkat T cells, as well as the addition of GZMA recombinant protein, was used to validate the predicted pair of GZMA and coagulation factor II thrombin receptor (F2R) by RT‐PCR, angiogenesis and migration assays. Results: A transcriptomic atlas of 44 746 individual cells was constructed from the periapical lesions of five patients with CAP by single‐cell RNA‐seq, and eight cell types were identified. We identified nine subsets of T cells and deciphered the cellular heterogeneity of T cells in CAP at the functional level by subclustering and GSEA. Lineage tracing revealed a distinct lineage of T cells in CAP and predicted the transition of the T cellular state upon CAP. GSEA revealed multiple biological processes and relevant angiogenesis genes upregulated in CAP T cells. GZMA‐F2R pairs were predicted by cell–cell interactions in CAP. High expression of GZMA and F2R was observed in the coculture of HUVECs and Jurkat T cells, and the proangiogenic capacity of the GZMA recombinant protein was emphasized by in vitro experiments. Conclusions: Our study provides novel insights into the heterogeneity of T cells in periapical lesions and reveals the potential role of GZMA in T cells in regulating angiogenesis in HUVECs. [ABSTRACT FROM AUTHOR]

Infectious laryngotracheitis (ILT) is an acute respiratory disease of poultry caused by infectious laryngotracheitis virus (ILTV). Control of the disease with live attenuated vaccines administered via eye drop build upon immune responses generated by the eye-associated lymphoid tissues. The aim of this study was to assess cytokine and lymphocyte changes in the conjunctiva-associated lymphoid tissues (CALT) and Harderian gland (HG) stimulated by the ocular inoculation of the ILTV chicken embryo origin (CEO) vaccine strain and virulent strain 63140. This study offers strong evidence to support the roles that the CALT and HG play in the development of protective ILTV immune responses. It supports the premise that ILTV-mediated immunomodulation favors the B cell response over those of T cells. Further, it provides evidence that expansions of CD8α+ cells, with the concomitant expression of the Granzyme A gene, are key to reducing viral genomes in the CALT and halting ILTV cytolytic replication in the conjunctiva. Ultimately, this study revealed that the early upregulation of interleukin (IL)-12p40 and Interferon (IFN)-γ cytokine genes, which shape the antigen-specific cell-mediated immune responses, retarded the decline of virus replication, and enhanced the development of lesions in the conjunctiva epithelium.

Abstract Background Increased frequency of circulating double negative T (DNT, CD4−CD8−CD3+) cells with protective immune function has been observed in human immunodeficiency virus (HIV) infection and tuberculosis (TB). Here the role of circulating TCRαβ+ DNT cells was further investigated in HIV/TB co-infection. Methods A cross-sectional study was conducted to investigate the frequency and functional profiles of peripheral TCRαβ+ DNT cells including apoptosis, chemokine and cytokine expression among healthy individuals and patients with TB, HIV infection and HIV/TB co-infection by cell surface staining and intracellular cytokine staining combined with flow cytometry. Results Significantly increased frequency of TCRαβ+ DNT cells was observed in HIV/TB co-infection than that in TB (p

Background: Several studies implicate Th17-cells and its cytokine (IL-17) in disease pathogenesis of spondyloarthritis (SpA), with available evidence supporting a pathogenic role of CD8+ T-cells. However, data on the involvement of CD8+ mucosal-associated invariant T-cells (MAIT) and their phenotypic characterization and inflammatory function including IL-17 and Granzyme A production in a homogenous population of SpApatients with primarily axial disease (axSpA) are lacking. Objectives: Quantify and characterize the phenotype and function of circulating CD8+MAIT-cells in axSpA-patients with primarily axial disease. Methods: Blood samples were obtained from 41 axSpA-patients and 30 age- and sex-matched healthy controls (HC). Numbers and percentages of MAIT-cells (defined as CD3+CD8+CD161highTCRVa7.2 +) were determined, and production of IL-17 and Granzyme A (GrzA) by MAIT-cells were examined by flow cytometry upon in vitro stimulation. Serum IgG specific for CMV was measured by ELISA. Results: No significant differences in numbers and percentages of circulating MAIT-cells were found between axSpA-patients and HCr zijn meer resultaten de centrale memory CD8 T cellen. cellen van patirculating MAIT cells.. Further phenotypic analysis revealed a significant decrease in numbers of central memory MAIT-cells of axSpA-patients compared to HC. The decrease in central memory MAIT-cells in axSpA patients was not attributed to an alteration in CD8 T-cell numbers, but correlated inversely with serum CMVIgG titers. Production of IL-17 by MAIT-cells was comparable between axSpApatients and HC, whereas a significant decrease in the production of GrzA by MAIT-cells from axSpA-patients was observed. Conclusions: The decrease in cytotoxic capability of circulating MAIT-cells in axSpA-patients might implicate that these cell types migrate to the inflamed tissue and therefore associate with the axial disease pathogenesis. [ABSTRACT FROM AUTHOR]

BackgroundSeveral studies implicate Th17-cells and its cytokine (IL-17) in disease pathogenesis of spondyloarthritis (SpA), with available evidence supporting a pathogenic role of CD8+ T-cells. However, data on the involvement of CD8+ mucosal-associated invariant T-cells (MAIT) and their phenotypic characterization and inflammatory function including IL-17 and Granzyme A production in a homogenous population of SpA-patients with primarily axial disease (axSpA) are lacking.ObjectivesQuantify and characterize the phenotype and function of circulating CD8+MAIT-cells in axSpA-patients with primarily axial disease.MethodsBlood samples were obtained from 41 axSpA-patients and 30 age- and sex-matched healthy controls (HC). Numbers and percentages of MAIT-cells (defined as CD3+CD8+CD161highTCRVα7.2+) were determined, and production of IL-17 and Granzyme A (GrzA) by MAIT-cells were examined by flow cytometry upon in vitro stimulation. Serum IgG specific for CMV was measured by ELISA.ResultsNo significant differences in numbers and percentages of circulating MAIT-cells were found between axSpA-patients and HCr zijn meer resultaten de centrale memory CD8 T cellen. cellen van patirculating MAIT cells.. Further phenotypic analysis revealed a significant decrease in numbers of central memory MAIT-cells of axSpA-patients compared to HC. The decrease in central memory MAIT-cells in axSpA patients was not attributed to an alteration in CD8 T-cell numbers, but correlated inversely with serum CMV-IgG titers. Production of IL-17 by MAIT-cells was comparable between axSpA-patients and HC, whereas a significant decrease in the production of GrzA by MAIT-cells from axSpA-patients was observed.ConclusionsThe decrease in cytotoxic capability of circulating MAIT-cells in axSpA-patients might implicate that these cell types migrate to the inflamed tissue and therefore associate with the axial disease pathogenesis.

Background: Increased frequency of circulating double negative T (DNT, CD4-CD8-CD3+) cells with protective immune function has been observed in human immunodeficiency virus (HIV) infection and tuberculosis (TB). Here the role of circulating TCRαβ+ DNT cells was further investigated in HIV/TB co-infection.Methods: A cross-sectional study was conducted to investigate the frequency and functional profiles of peripheral TCRαβ+ DNT cells including apoptosis, chemokine and cytokine expression among healthy individuals and patients with TB, HIV infection and HIV/TB co-infection by cell surface staining and intracellular cytokine staining combined with flow cytometry.Results: Significantly increased frequency of TCRαβ+ DNT cells was observed in HIV/TB co-infection than that in TB (p < 0.001), HIV infection (p = 0.039) and healthy controls (p < 0.001). Compared with TB, HIV/TB co-infection had higher frequency of Fas expression (p = 0.007) and lower frequency of Annexin V expression on TCRαβ+ DNT cells (p = 0.049), and the frequency of Annexin V expression on Fas+TCRαβ+ DNT cells had no significant difference. TCRαβ+ DNT cells expressed less CCR5 in HIV/TB co-infection than that in TB (p = 0.014), and more CXCR4 in HIV/TB co-infection than that in HIV infection (p = 0.043). Compared with healthy controls, TB and HIV/TB co-infection had higher frequency of TCRαβ+ DNT cells secreting Granzyme A (p = 0.046; p = 0.005). In TB and HIV/TB co-infection, TCRαβ+ DNT cells secreted more granzyme A (p = 0.002; p = 0.002) and perforin (p < 0.001; p = 0.017) than CD4+ T cells but similar to CD8+ T cells.Conclusions: Reduced apoptosis may take part in the mechanism of increased frequency of peripheral TCRαβ+ DNT cells in HIV/TB co-infection. TCRαβ+ DNT cells may play a cytotoxic T cells-like function in HIV/TB co-infection. [ABSTRACT FROM AUTHOR]

Granzyme A (gzmA), a serine protease involved in the modulation of the inflammatory immune response, is found at an elevated level in the serum from ALS patients. However, the influence of gzmA on the progression of ALS remains unclear. The aim of our work was to assess whether the absence of gzmA in an ALS murine model could help slow down the progression of the disease. Homozygous and hemizygous gzmA-deficient mice expressing the hSOD1G93A transgene were generated, and survival of these mice was monitored. Subsequently, gene and protein expression of inflammatory and oxidative stress markers was measured in the spinal cord and quadriceps of these mice. We observed the longest lifespan in gzmA+/− mice. GzmA gene and protein expression was downregulated in the spinal cord and serum from gmzA+/− mice, confirming that the increased survival of hemizygous mice is correlated with lower levels of gzmA. In addition, mRNA and protein levels of glutathione reductase (GSR), involved in oxidative stress, were found downregulated in the spinal cord and quadriceps of gmzA+/− mice, together with lower IL-1β and IL-6 mRNA levels in hemyzigous mice. In summary, our findings indicate for the first time that reduced levels, but not the absence, of gzmA could slightly ameliorate the disease progression in this animal model. [ABSTRACT FROM AUTHOR]

BackgroundTuberculosis (TB) is an important opportunistic infection in acquired immunodeficiency diseases (AIDS). Although the frequency of CD4+CD8+ double-positive (DP) T cells has been observed to increase in pathological conditions, their role (phenotypic and functional) is poorly described, especially in human immunodeficiency virus (HIV) infection with TB (HIV/TB (HT) coinfection).MethodsThe percentage and phenotypic and functional properties of peripheral blood DP T cells in patients with HT coinfection in comparison to uninfected controls and to patients with HIV or TB mono-infection were analyzed by direct intracellular cytokine staining (ICS).ResultsTotal and CD4lowCD8high DP T cells were significantly increased in patients with both HIV and TB mono-infection, especially in patients with HT coinfection. Compared with healthy controls (HCs), the percentage of DP T cells expressing chemokine receptor 5 (CCR5) in patients with HT coinfection was significantly higher. Compared with HCs and patients with TB, a lower percentage of tumor necrosis factor α (TNF-α) secreting DP T cells and a higher percentage of granzyme A-secreting DP T cells were observed in patients with HIV mono-infection and HT coinfection, respectively. In addition, DP T cells expressed more cytolytic markers (granzyme A and perforin) than CD4+ T cells, but similarly to CD8+ T cells in patients with HT coinfection.ConclusionsOur data suggested that HT coinfection resulted in a marked increase in DP T cells, especially the CD4lowCD8high subpopulation. DP T cells may be susceptible to HT coinfection, and have the same cytotoxic function as CD8+ T cells.

Cytotoxic lymphocytes release proteins contained within the cytoplasmic cytolytic granules after recognition of infected or tumor target cells. These cytotoxic granular proteins (namely granzymes, granulysin, and perforin) are key immunological mediators within human cellular immunity. The availability of highly purified cytotoxic proteins has been fundamental for understanding their function in immunity and mechanistic involvement in sepsis and autoimmunity. Methods for recovery of native cytotoxic proteins can be problematic leading to: 1) the co-purification of additional proteins, confounding interpretation of function, and 2) low yields of highly purified proteins. Recombinant protein expression of individual cytolytic components can overcome these challenges. The use of mammalian expression systems is preferred for optimal post-translational modifications and avoidance of endotoxin contamination. Some of these proteins have been proposed for host directed human therapies (e.g. - granzyme A), or treatment of systemic infections or tumors as in granulysin. We report here a novel expression system using HEK293T cells for cost-effective purification of high yields of human granzymes (granzyme A and granzyme B) and granulysin with enhanced biological activity than previous reports. The resulting proteins are free of native contaminants, fold correctly, and remain enzymatically active. Importantly, these improvements have also led to the first purification of biologically active recombinant human granulysin in high yields from a mammalian system. This method can be used as a template for purification of many other secreted cellular proteins and may lead to advances for human medicine.

Granzyme A (GZMA) is a serine protease secreted by cytotoxic lymphocytes, with Gzma-/- mouse studies having informed our understanding of GZMA’s physiological function. We show herein that Gzma-/- mice have a mixed C57BL/6J and C57BL/6N genetic background and retain the full-length nicotinamide nucleotide transhydrogenase (Nnt) gene, whereas Nnt is truncated in C57BL/6J mice. Chikungunya viral arthritis was substantially ameliorated in Gzma-/- mice; however, the presence of Nnt and the C57BL/6N background, rather than loss of GZMA expression, was responsible for this phenotype. A new CRISPR active site mutant C57BL/6J GzmaS211A mouse provided the first insights into GZMA’s bioactivity free of background issues, with circulating proteolytically active GZMA promoting immune-stimulating and pro-inflammatory signatures. Remarkably, k-mer mining of the Sequence Read Archive illustrated that ≈27% of Run Accessions and ≈38% of BioProjects listing C57BL/6J as the mouse strain had Nnt sequencing reads inconsistent with a C57BL/6J genetic background. Nnt and C57BL/6N background issues have clearly complicated our understanding of GZMA and may similarly have influenced studies across a broad range of fields.

Cytotoxic lymphocytes release proteins contained within the cytoplasmic cytolytic granules after recognition of infected or tumor target cells. These cytotoxic granular proteins (namely granzymes, granulysin, and perforin) are key immunological mediators within human cellular immunity. The availability of highly purified cytotoxic proteins has been fundamental for understanding their function in immunity and mechanistic involvement in sepsis and autoimmunity. Methods for recovery of native cytotoxic proteins can be problematic leading to: 1) the co-purification of additional proteins, confounding interpretation of function, and 2) low yields of highly purified proteins. Recombinant protein expression of individual cytolytic components can overcome these challenges. The use of mammalian expression systems is preferred for optimal post-translational modifications and avoidance of endotoxin contamination. Some of these proteins have been proposed for host directed human therapies (e.g. - granzyme A), or treatment of systemic infections or tumors as in granulysin. We report here a novel expression system using HEK293T cells for cost-effective purification of high yields of human granzymes (granzyme A and granzyme B) and granulysin with enhanced biological activity than previous reports. The resulting proteins are free of native contaminants, fold correctly, and remain enzymatically active. Importantly, these improvements have also led to the first purification of biologically active recombinant human granulysin in high yields from a mammalian system. This method can be used as a template for purification of many other secreted cellular proteins and may lead to advances for human medicine. [ABSTRACT FROM AUTHOR]

Type 1 innate lymphoid cells (ILC1) are tissue‐resident lymphocytes that provide early protection against bacterial and viral infections. Discrete transcriptional states of ILC1 have been identified in homeostatic and pathological contexts. However, whether these states delineate ILC1 with different functional properties is not completely understood. Here, we show that liver ILC1 are heterogeneous for the expression of distinct effector molecules and surface receptors, including granzyme A (GzmA) and CD160, in mice. ILC1 expressing high levels of GzmA are enriched in the liver of adult mice, and represent the main hepatic ILC1 population at birth. However, the heterogeneity of GzmA and CD160 expression in hepatic ILC1 begins perinatally and increases with age. GzmA+ ILC1 differ from NK cells for the limited homeostatic requirements of JAK/STAT signals and the transcription factor Nfil3. Moreover, by employing Rorc(γt)‐fate map (fm) reporter mice, we established that ILC3‐ILC1 plasticity contributes to delineate the heterogeneity of liver ILC1, with RORγt‐fm+ cells skewed toward a GzmA–CD160+ phenotype. Finally, we showed that ILC1 defined by the expression of GzmA and CD160 are characterized by graded cytotoxic potential and ability to produce IFN‐γ. In conclusion, our findings help deconvoluting ILC1 heterogeneity and provide evidence for functional diversification of liver ILC1. [ABSTRACT FROM AUTHOR]

Mycobacterium tuberculosis (Mtb), the pathological agent that causes tuberculosis (TB) is the number one infectious killer worldwide with one fourth of the world’s population currently infected. Data indicate that γ9δ2 T cells secrete Granzyme A (GzmA) in the extracellular space triggering the infected monocyte to inhibit growth of intracellular mycobacteria. Accordingly, deletion of GZMA from γ9δ2 T cells reverses their inhibitory capacity. Through mechanistic studies, GzmA’s action was investigated in monocytes from human PBMCs. The use of recombinant human GzmA expressed in a mammalian system induced inhibition of intracellular mycobacteria to the same degree as previous human native protein findings. Our data indicate that: 1) GzmA is internalized within mycobacteria-infected cells, suggesting that GzmA uptake could prevent infection and 2) that the active site is not required to inhibit intracellular replication. Global proteomic analysis demonstrated that the ER stress response and ATP producing proteins were upregulated after GzmA treatment, and these proteins abundancies were confirmed by examining their expression in an independent set of patient samples. Our data suggest that immunotherapeutic host interventions of these pathways may contribute to better control of the current TB epidemic.

Mycobacterium tuberculosis (Mtb), the pathological agent that causes tuberculosis (TB) is the number one infectious killer worldwide with one fourth of the world's population currently infected. Data indicate that γ9δ2 T cells secrete Granzyme A (GzmA) in the extracellular space triggering the infected monocyte to inhibit growth of intracellular mycobacteria. Accordingly, deletion of GZMA from γ9δ2 T cells reverses their inhibitory capacity. Through mechanistic studies, GzmA's action was investigated in monocytes from human PBMCs. The use of recombinant human GzmA expressed in a mammalian system induced inhibition of intracellular mycobacteria to the same degree as previous human native protein findings. Our data indicate that: 1) GzmA is internalized within mycobacteria-infected cells, suggesting that GzmA uptake could prevent infection and 2) that the active site is not required to inhibit intracellular replication. Global proteomic analysis demonstrated that the ER stress response and ATP producing proteins were upregulated after GzmA treatment, and these proteins abundancies were confirmed by examining their expression in an independent set of patient samples. Our data suggest that immunotherapeutic host interventions of these pathways may contribute to better control of the current TB epidemic. [ABSTRACT FROM AUTHOR]

Background Sepsis-related acute kidney injury (AKI) is associated with high morbidity and mortality among patients. Underlying pathomechanisms include capillary leakage and fluid loss into the interstitial tissue and constant exposure to pathogens results in activation of inflammatory cascades, organ dysfunction and subsequently organ damage. Methods To identify novel factors that trigger sepsis-related acute kidney injury, plasma levels of Granzyme A, as representative of a lymphocyte-derived protease, and heparin-binding protein as indicator for neutrophil-derived mediators, were investigated retrospectively in 60 sepsis patients. Results While no association was found between plasma levels of lymphocyte-derived Granzyme A and the incidence of sepsis-related AKI, sepsis patients with AKI had significantly higher plasma levels of heparin-binding protein compared to those without AKI. This applies both to heparin-binding protein peak values (43.30 ± 23.34 vs. 30.25 ± 15.63 pg/mL; p = 0.005) as well as mean values (27.93 ± 14.39 vs. 22.02 ± 7.65 pg/mL; p = 0.021). Furthermore, a heparin-binding protein cut-off value of 23.89 pg/mL was established for AKI diagnosis. Conclusion This study identifies the neutrophil-derived heparin-binding protein as a valuable new biomarker for AKI in sepsis. Beyond the diagnostic perspective, this offers prospect for further research on pathogenesis of AKI and novel therapeutic approaches.

The functional characterization and regulation of tissue resident and non-resident CD8+ T cells in the human female reproductive tract (FRT) as women age remains a gap in our knowledge. Here we characterized the cytotoxic activity and granular contents of CD8+ T cells from the FRT in pre- and postmenopausal women. We found that under steady-state conditions, CD8+ T cells from endometrium (EM), endocervix and ectocervix displayed direct cytotoxic activity, and that cytotoxicity increased in the EM after menopause. Cytotoxic activity was sensitive to suppression by TGFβ exclusively in the EM, and sensitivity to TGFβ was reduced after menopause. Under steady-state conditions, cytotoxic activity (measured as direct killing activity), cytotoxic potential (measured as content of cytotoxic molecules) and proliferation are enhanced in non-resident CD8+ (CD103−) T cells compared to tissue resident (CD103+) T cells. Upon activation, CD103+ T cells displayed greater degranulation compared to CD103− T cells, however the granular content of perforin, granzyme A (GZA) or granzyme B (GZB) was significantly lower. After menopause, degranulation significantly increased, and granular release switched from predominantly GZB in premenopausal to GZA in postmenopausal women. Postmenopausal changes affected both CD103+ and CD103− subpopulations. Finally, CD103+ T cells displayed reduced proliferation compared to CD103− T cells, but after proliferation, cytotoxic molecules were similar in each population. Our results highlight the complexity of regulation of cytotoxic function in the FRT before and after menopause, and are relevant to the development of protective strategies against genital infections and gynecological cancers as women age.

Granzyme A (GrA) has long been recognized as one of the key players in the induction of cell death of neoplastic, foreign or infected cells after granule delivery by cytotoxic cells. While the cytotoxic potential of GrA is controversial in current literature, accumulating evidence now indicates roles for extracellular GrA in modulating inflammation and inflammatory diseases. This paper aims to explore the literature presenting current knowledge on GrA as an extracellular modulator of inflammation by summarizing (i) the presence and role of extracellular GrA in several inflammatory diseases, and (ii) the potential molecular mechanisms of extracellular GrA in augmenting inflammation.

The functional characterization and regulation of tissue resident and non-resident CD8+ T cells in the human female reproductive tract (FRT) as women age remains a gap in our knowledge. Here we characterized the cytotoxic activity and granular contents of CD8+ T cells from the FRT in pre- and postmenopausal women. We found that under steady-state conditions, CD8+ T cells from endometrium (EM), endocervix and ectocervix displayed direct cytotoxic activity, and that cytotoxicity increased in the EM after menopause. Cytotoxic activity was sensitive to suppression by TGFβ exclusively in the EM, and sensitivity to TGFβ was reduced after menopause. Under steady-state conditions, cytotoxic activity (measured as direct killing activity), cytotoxic potential (measured as content of cytotoxic molecules) and proliferation are enhanced in non-resident CD8+ (CD103−) T cells compared to tissue resident (CD103+) T cells. Upon activation, CD103+ T cells displayed greater degranulation compared to CD103− T cells, however the granular content of perforin, granzyme A (GZA) or granzyme B (GZB) was significantly lower. After menopause, degranulation significantly increased, and granular release switched from predominantly GZB in premenopausal to GZA in postmenopausal women. Postmenopausal changes affected both CD103+ and CD103− subpopulations. Finally, CD103+ T cells displayed reduced proliferation compared to CD103− T cells, but after proliferation, cytotoxic molecules were similar in each population. Our results highlight the complexity of regulation of cytotoxic function in the FRT before and after menopause, and are relevant to the development of protective strategies against genital infections and gynecological cancers as women age. [ABSTRACT FROM AUTHOR]

Granzyme A (GrA) has long been recognized as one of the key players in the induction of cell death of neoplastic, foreign or infected cells after granule delivery by cytotoxic cells. While the cytotoxic potential of GrA is controversial in current literature, accumulating evidence now indicates roles for extracellular GrA in modulating inflammation and inflammatory diseases. This paper aims to explore the literature presenting current knowledge on GrA as an extracellular modulator of inflammation by summarizing (i) the presence and role of extracellular GrA in several inflammatory diseases, and (ii) the potential molecular mechanisms of extracellular GrA in augmenting inflammation. [ABSTRACT FROM AUTHOR]

In our study, we aimed to establish expression of cytotoxic CD8+ T cells in the decidua basalis and the maternal peripheral blood (mPBL) of severe and mild preeclampsia (PE) and compare to healthy pregnancies. Decidual tissue and mPBL of 10 women with mild PE, 10 women with severe PE, and 20 age-matched healthy pregnancy controls were analyzed by double immunofluorescence and qPCR, respectively. By double immunofluorescence staining, we found a decreased total number of cells/mm2 in decidua basalis of granulysin (GNLY)+ (p ˂ 0.0001), granzyme B (GzB)+(p ˂ 0.0001), GzB+CD8+(p ˂ 0.0001), perforin (PRF1)+ (p ˂ 0.0001), and PRF1+CD8+ (p ˂ 0.01) in the severe PE compared to control group. Additionally, we noticed the trend of lower mRNA expression for GNLY, granzyme A (GZMA), GzB, and PRF1 in CD8+ T cells of mPBL in mild and severe PE, with the latter marker statistically decreased in severe PE (p ˂ 0.001). Forkhead box P3 (FOXP3) mRNA in CD8+ T cells mPBL was increased in mild PE (p ˂ 0.001) compared to controls. In conclusion, severe PE is characterized by altered expression of cytotoxic CD8+ T cells in decidua and mPBL, suggesting their role in pathophysiology of PE and fetal-maternal immune tolerance.

Granzyme A (GzmA) is secreted by cytotoxic lymphocytes and has traditionally been viewed as a mediator of cell death. However, a growing body of data suggests the physiological role of GzmA is promotion of inflammation. Here, we show that GzmA is significantly elevated in the sera of chikungunya virus (CHIKV) patients and that GzmA levels correlated with viral loads and disease scores in these patients. Serum GzmA levels were also elevated in CHIKV mouse models, with NK cells the likely source. Infection of mice deficient in type I interferon responses with CHIKV, Zika virus, or dengue virus resulted in high levels of circulating GzmA. We also show that subcutaneous injection of enzymically active recombinant mouse GzmA was able to mediate inflammation, both locally at the injection site as well as at a distant site. Protease activated receptors (PARs) may represent targets for GzmA, and we show that treatment with PAR antagonist ameliorated GzmA- and CHIKV-mediated inflammation.

Granzymes (Gzm) are serine proteases, contained into the secretory granules of cytotoxic cells, responsible for the cell-mediated cytotoxicity (CMC) against tumor cells and intracellular pathogens such as virus and bacteria. In fish, they have received little attention to their existence, classification or functional characterization. Therefore, we aimed to identify and evaluate their functional and transcriptomic relevance in the innate CMC activity of two relevant teleost fish species, gilthead seabream and European sea bass. Afterwards, we wanted to focus on their regulation upon nodavirus (NNV) infection, a virus that causes great mortalities to sea bass specimens while seabream is resistant. In this study, we have identified genes encoding GzmA and GzmB in both seabream and sea bass, as well as GzmM in seabream, which showed good phylogenetic relation to their mammalian orthologs. In addition, we found enzymatic activity related to tryptase (GzmA and/or GzmK), aspartase (GzmB), metase (GzmM), or chymase (GzmH) in resting head-kidney leucocytes (HKLs), with the following order of activity: GzmA/K ~ GzmM >> GzmH >>> GzmB. In addition, during innate CMC assays consisting on HKLs exposed to either mock- or NNV-infected target cells, though all the granzyme transcripts were increased only the tryptase activity did. Thus, our data suggest a high functional activity of GzmA/K in the innate CMC and a marginal one for GzmB. Moreover, GzmB activity was detected into target cells during the CMC assays. However, the percentage of target cells with GzmB activity after the CMC assays was about 10-fold lower than the death target cells, demonstrating that GzmB is not the main inductor of cell death. Moreover, in in vivo infection with NNV, gzm transcription is differently regulated depending on the fish species, genes and tissues. However, the immunohistochemistry study revealed an increased number of GzmB stained cells and areas in the brain of seabream after NNV infection, which was mainly associated with the lesions detected. Further studies are needed to ascertain the molecular nature, biological function and implication of fish granzymes in the CMC activity, and in the antiviral defense in particular.

Granzyme A (GzmA), together with perforin, are well-known for their cytotoxic activity against tumor or virus-infected cells. In addition to this cytotoxic function, GzmA stimulates several immune cell types and induces inflammation in the absence of perforin, however, its effect on the dendritic cell (DC) is unknown. In the current study, we showed that recombinant GzmA induced the phenotypic maturation of plasmacytoid DCs (pDCs) and conventional DCs (cDCs), but not their apoptosis. Particularly, GzmA made pDCs more functional, thus leading to production of type I interferon (IFN) via the TLR9-MyD88 pathway. We also demonstrated that GzmA binds TLR9 and co-localizes with it in endosomes. When co-administered with antigen, GzmA acted as a powerful adjuvant for eliciting antigen-specific cytotoxic CD8+ T lymphocytes (CTLs) that protected mice from tumor challenge. The induction of CTL was completely abolished in XCR1+ DC-depleted mice, whereas it was reduced to less than half in pDC-depleted or IFN-α/β receptor knockout mice. Thus, CTL cross-priming was dependent on XCR1+cDC and also type I IFN, which was produced by GzmA-activated pDCs. These results indicate that GzmA -stimulated pDCs enhance the cross-priming activity of cDCs in situ. We also showed that the adjuvant effect of GzmA is superior to CpG-ODN and LPS. Our findings highlight the ability of GzmA to bridge innate and adaptive immune responses via pDC help and suggest that GzmA may be useful as a vaccine adjuvant.

Objective: The present study aimed to determine whether granzymes are implicated in the pathogenesis of infection-associated acute encephalopathy (AE). Methods: We investigated granzyme and cytokine levels in the cerebrospinal fluid of patients with acute encephalopathy or complex febrile seizures (cFS). A total of 24 acute encephalopathy patients and 22 complex febrile seizures patients were included in the present study. Levels of granzymes A and B were measured using enzyme-linked immunosorbent assay, and levels of tumor necrosis factor α (TNF-α), interferon-γ (IFN-γ), interleukin 1β (IL-1β), IL-1 receptor antagonist (IL-1RA), IL-4, IL-6, IL-8, and IL-10 were assessed using the Bio-Plex suspension array system. Results: Cerebrospinal fluid levels of granzyme A were significantly higher, and those of TNF-α and IL-1RA were significantly lower in the AE group than in the cFS group; however, no significant differences in the levels of granzyme B, IFN-γ, IL-1β, IL-4, IL-6, IL-8, and IL-10 were observed between the 2 groups. In addition, no significant differences in granzyme A, granzyme B, or cytokine levels were observed between acute encephalopathy patients with and those without neurologic sequelae. Conclusions: Our findings indicate the involvement of granzyme A in the pathogenesis of acute encephalopathy. [ABSTRACT FROM AUTHOR]

Granzyme A (GzmA) is secreted by cytotoxic lymphocytes and has traditionally been viewed as a mediator of cell death. However, a growing body of data suggests the physiological role of GzmA is promotion of inflammation. Here, we show that GzmA is significantly elevated in the sera of chikungunya virus (CHIKV) patients and that GzmA levels correlated with viral loads and disease scores in these patients. Serum GzmA levels were also elevated in CHIKV mouse models, with NK cells the likely source. Infection of mice deficient in type I interferon responses with CHIKV, Zika virus, or dengue virus resulted in high levels of circulating GzmA. We also show that subcutaneous injection of enzymically active recombinant mouse GzmA was able to mediate inflammation, both locally at the injection site as well as at a distant site. Protease activated receptors (PARs) may represent targets for GzmA, and we show that treatment with PAR antagonist ameliorated GzmA- and CHIKV-mediated inflammation. [ABSTRACT FROM AUTHOR]

Granzymes (Gzm) are serine proteases, contained into the secretory granules of cytotoxic cells, responsible for the cell-mediated cytotoxicity (CMC) against tumor cells and intracellular pathogens such as virus and bacteria. In fish, they have received little attention to their existence, classification or functional characterization. Therefore, we aimed to identify and evaluate their functional and transcriptomic relevance in the innate CMC activity of two relevant teleost fish species, gilthead seabream and European sea bass. Afterwards, we wanted to focus on their regulation upon nodavirus (NNV) infection, a virus that causes great mortalities to sea bass specimens while seabream is resistant. In this study, we have identified genes encoding GzmA and GzmB in both seabream and sea bass, as well as GzmM in seabream, which showed good phylogenetic relation to their mammalian orthologs. In addition, we found enzymatic activity related to tryptase (GzmA and/or GzmK), aspartase (GzmB), metase (GzmM), or chymase (GzmH) in resting head-kidney leucocytes (HKLs), with the following order of activity: GzmA/K ~ GzmM >> GzmH >>> GzmB. In addition, during innate CMC assays consisting on HKLs exposed to either mock- or NNV-infected target cells, though all the granzyme transcripts were increased only the tryptase activity did. Thus, our data suggest a high functional activity of GzmA/K in the innate CMC and a marginal one for GzmB. Moreover, GzmB activity was detected into target cells during the CMC assays. However, the percentage of target cells with GzmB activity after the CMC assays was about 10-fold lower than the death target cells, demonstrating that GzmB is not the main inductor of cell death. Moreover, in in vivo infection with NNV, gzm transcription is differently regulated depending on the fish species, genes and tissues. However, the immunohistochemistry study revealed an increased number of GzmB stained cells and areas in the brain of seabream after NNV infection, which was mainly associated with the lesions detected. Further studies are needed to ascertain the molecular nature, biological function and implication of fish granzymes in the CMC activity, and in the antiviral defense in particular. [ABSTRACT FROM AUTHOR]

Granzyme A (GzmA), together with perforin, are well-known for their cytotoxic activity against tumor or virus-infected cells. In addition to this cytotoxic function, GzmA stimulates several immune cell types and induces inflammation in the absence of perforin, however, its effect on the dendritic cell (DC) is unknown. In the current study, we showed that recombinant GzmA induced the phenotypic maturation of plasmacytoid DCs (pDCs) and conventional DCs (cDCs), but not their apoptosis. Particularly, GzmA made pDCs more functional, thus leading to production of type I interferon (IFN) via the TLR9-MyD88 pathway. We also demonstrated that GzmA binds TLR9 and co-localizes with it in endosomes. When co-administered with antigen, GzmA acted as a powerful adjuvant for eliciting antigen-specific cytotoxic CD8+ T lymphocytes (CTLs) that protected mice from tumor challenge. The induction of CTL was completely abolished in XCR1+ DC-depleted mice, whereas it was reduced to less than half in pDC-depleted or IFN-α/β receptor knockout mice. Thus, CTL cross-priming was dependent on XCR1+cDC and also type I IFN, which was produced by GzmA-activated pDCs. These results indicate that GzmA -stimulated pDCs enhance the cross-priming activity of cDCs in situ. We also showed that the adjuvant effect of GzmA is superior to CpG-ODN and LPS. Our findings highlight the ability of GzmA to bridge innate and adaptive immune responses via pDC help and suggest that GzmA may be useful as a vaccine adjuvant. [ABSTRACT FROM AUTHOR]

BackgroundRecently, immune-checkpoint blockade has shown striking clinical results in different cancer patients. However, a significant inter-individual and inter-tumor variability exists among different cancers. The expression of the toxins granzyme A (GZMA) and perforin 1 (PRF1), secreted by effector cytotoxic T cells and natural killer (NK) cells, were recently used as a denominator of the intratumoral immune cytolytic activity (CYT). These levels are significantly elevated upon CD8+ T-cell activation as well as during a productive clinical response against immune-checkpoint blockade therapies. Still, it is not completely understood how different tumors induce and adapt to immune responses.MethodsHere, we calculated the CYT across different cancer types and focused on differences between primary and metastatic tumors. Using data from 10,355, primary tumor resection samples and 2,787 normal samples that we extracted from The Cancer Genome Atlas and Genotype-Tissue Expression project databases, we screened the variation of CYT across 32 different cancer types and 28 different normal tissue types. We correlated the cytolytic levels in each cancer type with the corresponding patient group’s overall survival, the expression of several immune-checkpoint molecules, as well as with the load of tumor-infiltrating lymphocytes (TILs), and tumor-associated neutrophils (TANs) in these tumors.ResultsWe found diverse levels of CYT across different cancer types, with highest levels in kidney, lung, and cervical cancers, and lowest levels in glioma, adrenocortical carcinoma (ACC), and uveal melanoma. GZMA protein was either lowly expressed or absent in at least half of these tumors; whereas PRF1 protein was not detected in almost any of the different tumor types, analyzing tissue microarrays from 20 different tumor types. CYT was significantly higher in metastatic skin melanoma and correlated significantly to the TIL load. In TCGA-ACC, skin melanoma, and bladder cancer, CYT was associated with an improved patient outcome and high levels of both GZMA and PRF1 synergistically affected patient survival in these cancers. In bladder, breast, colon, esophageal, kidney, ovarian, pancreatic, testicular, and thyroid cancers, high CYT was accompanied by upregulation of at least one immune-checkpoint molecule, indicating that similar to melanoma and prostate cancer, immune responses in cytolytic-high tumors elicit immune suppression in the tumor microenvironment.ConclusionOverall, our data highlight the existence of diverse levels of CYT across different cancer types and suggest that along with the existence of complicated associations among various tumor-infiltrated immune cells, it is capable to promote or inhibit the establishment of a permissive tumor microenvironment, depending on the cancer type. High levels of immunosuppression seem to exist in several tumor types.

Infectious laryngotracheitis (ILT) is an acute respiratory disease of poultry caused by infectious laryngotracheitis virus (ILTV). Control of the disease with live attenuated vaccines administered via eye drop build upon immune responses generated by the eye-associated lymphoid tissues. The aim of this study was to assess cytokine and lymphocyte changes in the conjunctiva-associated lymphoid tissues (CALT) and Harderian gland (HG) stimulated by the ocular inoculation of the ILTV chicken embryo origin (CEO) vaccine strain and virulent strain 63140. This study offers strong evidence to support the roles that the CALT and HG play in the development of protective ILTV immune responses. It supports the premise that ILTV-mediated immunomodulation favors the B cell response over those of T cells. Further, it provides evidence that expansions of CD8α+ cells, with the concomitant expression of the Granzyme A gene, are key to reducing viral genomes in the CALT and halting ILTV cytolytic replication in the conjunctiva. Ultimately, this study revealed that the early upregulation of interleukin (IL)-12p40 and Interferon (IFN)-γ cytokine genes, which shape the antigen-specific cell-mediated immune responses, retarded the decline of virus replication, and enhanced the development of lesions in the conjunctiva epithelium.

Background: Recently, immune-checkpoint blockade has shown striking clinical results in different cancer patients. However, a significant inter-individual and inter-tumor variability exists among different cancers. The expression of the toxins granzyme A (GZMA) and perforin 1 (PRF1), secreted by effector cytotoxic T cells and natural killer (NK) cells, were recently used as a denominator of the intratumoral immune cytolytic activity (CYT). These levels are significantly elevated upon CD8+ T-cell activation as well as during a productive clinical response against immune-checkpoint blockade therapies. Still, it is not completely understood how different tumors induce and adapt to immune responses. Methods: Here, we calculated the CYT across different cancer types and focused on differences between primary and metastatic tumors. Using data from 10,355, primary tumor resection samples and 2,787 normal samples that we extracted from The Cancer Genome Atlas and Genotype-Tissue Expression project databases, we screened the variation of CYT across 32 different cancer types and 28 different normal tissue types. We correlated the cytolytic levels in each cancer type with the corresponding patient group's overall survival, the expression of several immune-checkpoint molecules, as well as with the load of tumor-infiltrating lymphocytes (TILs), and tumor-associated neutrophils (TANs) in these tumors. Results: We found diverse levels of CYT across different cancer types, with highest levels in kidney, lung, and cervical cancers, and lowest levels in glioma, adrenocortical carcinoma (ACC), and uveal melanoma. GZMA protein was either lowly expressed or absent in at least half of these tumors; whereas PRF1 protein was not detected in almost any of the different tumor types, analyzing tissue microarrays from 20 different tumor types. CYT was significantly higher in metastatic skin melanoma and correlated significantly to the TIL load. In TCGA-ACC, skin melanoma, and bladder cancer, CYT was associated with an improved patient outcome and high levels of both GZMA and PRF1 synergistically affected patient survival in these cancers. In bladder, breast, colon, esophageal, kidney, ovarian, pancreatic, testicular, and thyroid cancers, high CYT was accompanied by upregulation of at least one immune-checkpoint molecule, indicating that similar to melanoma and prostate cancer, immune responses in cytolytic-high tumors elicit immune suppression in the tumor microenvironment. Conclusion: Overall, our data highlight the existence of diverse levels of CYT across different cancer types and suggest that along with the existence of complicated associations among various tumor-infiltrated immune cells, it is capable to promote or inhibit the establishment of a permissive tumor microenvironment, depending on the cancer type. High levels of immunosuppression seem to exist in several tumor types. [ABSTRACT FROM AUTHOR]

Objective: Natural killer (NK) cells have been involved in the pathology of different inflammatory and autoimmune disorders. Inflammation is an important regulator of osteoarthritis (OA), but the molecular and cellular mechanisms regulating this process are not well defined.Design: To understand the role of NK cells in OA, we have compared the phenotype (CD56 subsets and perforin and granzyme expression) and cytotoxic function of NK cells in peripheral blood and synovial fluid from patients with OA undergoing total knee arthroplasty.Results: In contrast to peripheral blood lymphocytes (PBLs), the majority of NK cells from the synovial fluid were CD56brightCD16(-) cells. As expected the expression of the cytolytic mediators perforin and granzyme B in CD56brightCD16(-) cells was low and correlated with a poor cytotoxic potential against K562 sensitive target cells. Surprisingly, this low cytotoxic NK cell subset expressed high levels of granzyme A (a protease recently characterized as a key modulator of inflammation in mouse models) in synovial fluid but not in peripheral blood. The presence of the CD56(+)brightCD16(-) cells expressing granzyme A correlated with increased levels of pro-inflammatory cytokines in synovial fluid from OA patients.Conclusion: Our results indicate that NK cells from the synovium of patients with OA, which present an immunoregulatory non-cytotoxic phenotype, show different phenotype comparing with NK cells from peripheral blood, especially expressing granzyme A, a pro-inflammatory molecule which may contribute to the establishment of chronic articular inflammation in this type of patients. [ABSTRACT FROM AUTHOR]

Streptococcus pneumoniae is the most common causative pathogen in community-acquired pneumonia (CAP). Granzyme A (GzmA) is a serine protease produced by a variety of cell types involved in the immune response. We sought to determine the role of GzmA on the host response during pneumococcal pneumonia. GzmA was measured in bronchoalveolar lavage fluid (BALF) harvested from CAP patients from the infected and contralateral uninfected side and in lung tissue slides from CAP patients and controls. In CAP patients, GzmA levels were increased in BALF obtained from the infected lung. Human lungs showed constitutive GzmA expression by both parenchymal and nonparenchymal cells. In an experimental setting, pneumonia was induced in wild-type (WT) and GzmA-deficient (GzmA−/−) mice by intranasal inoculation of S. pneumoniae. In separate experiments, WT and GzmA−/− mice were treated with natural killer (NK) cell depleting antibodies. Upon infection with S. pneumoniae, GzmA−/− mice showed a better survival and lower bacterial counts in BALF and distant body sites compared with WT mice. Although NK cells showed strong GzmA expression, NK cell depletion did not influence bacterial loads in either WT or GzmA−/− mice. These results implicate that GzmA plays an unfavorable role in host defense during pneumococcal pneumonia by a mechanism that does not depend on NK cells. [ABSTRACT FROM AUTHOR]

Cytotoxic cells of the immune system may kill infected or transformed host cells via the perforin/granzyme or the Fas ligand (FasL) pathways. The purpose of this study was to determine mRNA expression of perforin, granzyme A and FasL in Eimeria tenella-infected tissues at primary infection and infection of immune chickens as an indirect measure of cytotoxic cell activity. Chickens were rendered immune by repeated E. tenella infections, which were manifested as an absence of clinical signs or pathological lesions and significantly reduced oocyst production upon challenge infection. During primary E. tenella infection, perforin, granzyme A and FasL mRNA expression in caecal tissue was significantly increased at 10 days after infection, compared to uninfected birds. In contrast, at infection of immune birds, perforin and granzyme A mRNA expression in caecal tissue was significantly increased during the early stages of E. tenella challenge infection, days 1-4, which coincided with a substantial reduction of parasite replication in these birds. These results indicate the activation of cytotoxic pathways in immune birds and support a role for cytotoxic T cells in the protection against Eimeria infections. [ABSTRACT FROM AUTHOR]