Humoral Immune Response to CoronaVac in Turkish Adults.

While most approved vaccines are based on the viral spike protein or its immunogenic regions, inactivated whole-virion vaccines (e.g., CoronaVac) contain additional antigens that may enhance protection.

Frequent intrathecal production of antibodies to the viral capsid antigen of Epstein-Barr virus in patients with central nervous system post-transplant lymphoproliferative disorder.

Primary central nervous system post-transplant lymphoproliferative disorder (PCNS-PTLD) is strongly associated with Epstein-Barr virus (EBV). We analysed intrathecal production of EBV viral capsid antigen (VCA) immunoglobulin (Ig)G and IgA and Epstein-Barr nuclear antigen-1 (EBNA-1) IgG in nine patients with PNCS-PTLD and 20 patients with non-inflammatory neurological diseases (NINDs). Intrathecally produced VCA-IgG was detected in 7/9 (78%), VCA-IgA in 6/9 (67%) and EBNA-1-IgG in 2/9 (22%) patients with PCNS-PTLD, but not in NINDs.

Monitoring and functional characterization of the lymphocytic compartment in pancreatic ductal adenocarcinoma patients.

Background/objectives: Pancreatic ductal adenocarcinoma (PDAC) still has a poor prognosis and current treatments including immunotherapy often fail. This might be due to the pronounced immunosuppressive milieu impairing infiltration and function of immune effector cells. This study aimed at a comprehensive analysis of immune cells in PDAC patients by determining absolute and relative peripheral blood cell numbers of immune cell subsets along with their functional capacity.

Proteinase-activated receptor 2 promotes TGF-β-dependent cell motility in pancreatic cancer cells by sustaining expression of the TGF-β type I receptor ALK5.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by high expression of transforming growth factor (TGF)-β and the G protein-coupled receptor proteinase-activated receptor 2 (PAR2), the latter of which functions as a cell-surface sensor for serine proteinases asscociated with the tumour microenvironment. Since TGF-β and PAR2 affect tumourigenesis by regulating migration, invasion and metastasis, we hypothesized that there is signalling crosstalk between them. Depleting PDAC and non-PDAC cells of PAR2 by RNA interference strongly decreased TGF-β1-induced activation of Smad2/3 and p38 mitogen-activated protein kinase, Smad dependent transcriptional activity, expression of invasion associated genes, and cell migration/invasion in vitro.

Peripheral Blood Monocytes as Adult Stem Cells: Molecular Characterization and Improvements in Culture Conditions to Enhance Stem Cell Features and Proliferative Potential.

Adult stem or programmable cells hold great promise in diseases in which damaged or nonfunctional cells need to be replaced. We have recently demonstrated that peripheral blood monocytes can be differentiated in vitro into cells resembling specialized cell types like hepatocytes and pancreatic beta cells. During phenotypic conversion, the monocytes downregulate monocyte/macrophage differentiation markers, being indicative of partial dedifferentiation, and are partially reprogrammed to acquire a state of plasticity along with expression of various markers of pluripotency and resumption of mitosis.

The fatal alliance of cancer and T cells: How pancreatic tumor cells gather immunosuppressive T cells.

Immune evasion is a hallmark of cancer. We recently identified the adhesion molecule L1CAM as biomarker of pancreatic ductal adenocarcinoma (PDAC) associated with poor prognosis. During inflammation-associated carcinogenesis, L1CAM drives the enrichment of highly immunosuppressive CD4CD25CD69 T cells.

L1CAM promotes enrichment of immunosuppressive T cells in human pancreatic cancer correlating with malignant progression.

Regulatory T cell (T-reg) enrichment in the tumor microenvironment is regarded as an important mechanism of tumor immune escape. Hence, the presence of T-regs in highly malignant pancreatic ductal adenocarcinoma (PDAC) is correlated with short survival. Likewise, the adhesion molecule L1CAM is upregulated during PDAC progression in the pancreatic ductal epithelium also being associated with poor prognosis.

Tumor-associated macrophages exhibit pro- and anti-inflammatory properties by which they impact on pancreatic tumorigenesis.

Pancreatic ductal adenocarcinoma (PDAC) still ranking 4th in the order of fatal tumor diseases is characterized by a profound tumor stroma with high numbers of tumor-associated macrophages (TAMs). Driven by environmental factors, monocytes differentiate into M1- or M2-macrophages, the latter commonly regarded as being protumorigenic. Because a detailed analysis of TAMs in human PDAC development is still lacking, freshly isolated PDAC-derived TAMs were analyzed for their phenotype and impact on epithelial-mesenchymal-transition (EMT) of benign (H6c7) and malignant (Colo357) pancreatic ductal epithelial cells.

TGF-β1-dependent L1CAM expression has an essential role in macrophage-induced apoptosis resistance and cell migration of human intestinal epithelial cells.

Patients with chronic inflammatory bowel disease (IBD) have an increased risk to develop colorectal cancer (CRC) particularly after long duration of the disease. Chronic inflammation of the intestinal mucosa is characterized by a marked enrichment of immune cells such as macrophages as well as by high expression of cytokines and growth factors including transforming growth factor-beta 1 (TGF-β1). The adhesion molecule L1CAM mediates chemoresistance and migration of tumor cells and is elevated in CRC tissues being associated with metastatic spread and poor prognosis for the patients.

Inflammatory macrophages induce Nrf2 transcription factor-dependent proteasome activity in colonic NCM460 cells and thereby confer anti-apoptotic protection.

Adaptation of epithelial cells to persistent oxidative stress plays an important role in inflammation-associated carcinogenesis. This adaptation process involves activation of Nrf2 (nuclear factor-E2-related factor-2), which has been recently shown to contribute to carcinogenesis through the induction of proteasomal gene expression and proteasome activity. To verify this possible link between inflammation, oxidative stress, and Nrf2-dependent proteasome activation, we explored the impact of inflammatory (M1) macrophages on the human colon epithelial cell line NCM460.

The role of proteinase 3 (PR3) and the protease-activated receptor-2 (PAR-2) pathway in dendritic cell (DC) maturation of human-DC-like monocytes and murine DC.

Objectives: The aim of the study was to assess PAR-2 expression on dendritic cell (DC) subsets and other immune cells of Wegener's granulomatosis (WG) patients and healthy controls (HC) and to investigate whether Proteinase 3 (PR3, a serine protease which can activate PAR2) induces maturation of human DC-like monocytes and murine Flt-3 ligand- and GM-CSF-generated DC.

Methods: Human peripheral blood cells including DC subsets and Flt-3l- and GM-CSF-generated mouse DC were analysed for expression of PAR-2 and DC maturation markers by flow cytometry before and after stimulation with PR3, trypsin, PAR-2 agonist or LPS for 24 h.

Results: There was no difference of PAR-2 expression on PMNs, monocytes, lymphocytes and DC between all WG samples and HC.

The generation of programmable cells of monocytic origin involves partial repression of monocyte/macrophage markers and reactivation of pluripotency genes.

We have recently demonstrated that peripheral blood monocytes can be differentiated in vitro into hepatocyte-like cells using appropriate differentiation media. Phenotype conversion required prior in vitro culture in the presence of M-CSF, IL-3, and human serum, during which the cells acquired a state of plasticity, so were termed "programmable cells of monocytic origin" (PCMO). Here, we have further characterized the process of PCMO generation with respect to markers of monocyte-to-macrophage transition and pluripotency.

Peripheral blood CD14high CD16+ monocytes are main producers of IL-10.

Based on CD14 and CD16 expression, human peripheral blood monocytes (MO) can be divided into a major CD14(high) CD16(-) population and two minor CD14(high) CD16(+) and CD14(dim) CD16(+) subpopulations. CD14(dim) CD16(+) MO are well characterized and regarded as pro-inflammatory because upon stimulation produce TNF-alpha but little, if any, IL-10. By contrast, little is known about CD14(high) CD16(+) MO.

Anti-BDCA-4 (neuropilin-1) antibody can suppress virus-induced IFN-alpha production of plasmacytoid dendritic cells.

Plasmacytoid dendritic cells (PDC) in human blood are the main source of virus-induced interferon (IFN)-alpha. They exhibit a lineage-negative phenotype but all express BDCA-4, which is homologous to the neuronal receptor neuropilin-1. Specific staining with anti-BDCA-4 antibody is used for positive isolation of PDC from blood by magnetic cells sorting.

Synergistically upregulated interleukin-10 production in cocultures of monocytes and T cells after stimulation with respiratory syncytial virus.

Background: Respiratory syncytial virus (RSV) is known as a causal factor of severe bronchiolitis in young children. It has also been detected in patients with chronic obstructive pulmonary disease (COPD), a disease that is associated with an increased number of T cells in the bronchial mucosa. Here, we investigated the potential direct interaction between RSV and T cells and its impact on cytokine response.

In vitro-generated viral double-stranded RNA in contrast to polyinosinic:polycytidylic acid induces interferon-alpha in human plasmacytoid dendritic cells.

Double-stranded RNA (dsRNA) arises in the cytoplasm during viral replication and was shown to participate in the interferon (IFN)-alpha induction process. Besides the intracellular recognition, released dsRNA from dying, infected cells can function as a pathogen-associated molecular pattern (PAMP) for the innate immune system. In the present study, in vitro-generated dsRNA fragments of genomic sequences of Newcastle disease virus were used to induce IFN-alpha release in human peripheral blood mononuclear cells (PBMC), in immature myeloid dendritic cells (mDC) and in immature plasmacytoid DC (pDC).

Differential expression of IFN-alpha subtypes in human PBMC: evaluation of novel real-time PCR assays.

Studies of the human IFN-alpha subtype system have been hampered by the lack of efficient procedures to quantify and differentiate the expression of the highly homologous IFN-alpha subtypes. Here we evaluate four novel real-time PCR assays for the specific detection and quantification of IFN-alpha mRNA for the subtypes alpha(2), alpha(6), alpha(8) and alpha(1/13) in a combined assay in human peripheral blood mononuclear cells (PBMC). This included (a) the selection of beta-glucuronidase (GUS) as a suitable housekeeping gene for relative quantification; (b) verification of the specificity by using human DNA of different IFN-alpha subtypes; and (c) comparison of the amplification efficiencies among the different assays.

Platelet factor 4 inhibits proliferation and cytokine release of activated human T cells.

Platelet factor 4 (PF-4), a platelet-derived CXC chemokine, has been shown to induce the differentiation of monocytes into a subset of macrophages that lack the expression of HLA-DR Ag. This suggests a potential role for PF-4 in the modulation of monocyte-dependent T cell activation. Using an Ag-specific stimulation model in which T cells were cocultured with monocytes in the presence of recall Ags, we could show that under these conditions PF-4-treatment caused a strong decrease of T cell proliferation as well as of IFN-gamma release.

Atopic phenotype in children is associated with decreased virus-induced interferon-alpha release.

Background: Interferon-alpha (IFN-alpha) production in humans is an early event in the nonspecific cellular response to viruses and mediates a wide range of antiviral and immunoregulatory activities. Little is known about the role of IFN-alpha in allergic disease.

Methods: In the present study, we performed a retrospective comparative analysis of 88 children with and without an atopic phenotype for virus-induced IFN-alpha production in blood cultures.

Heterogeneity of human peripheral blood monocyte subsets.

In recent years the number of reports describing phenotypically and functionally distinct subsets of human blood leukocytes, and in particular of subtypes of antigen-presenting cells has continuously increased. A great diversity was described not only for dendritic cells (DC), but also for human blood monocytes (Mo) and macrophages (Mac). Similar to DC, the different types of Mo subsets could be defined by distinct phenotypes and immunoregulatory functions.

Identification of a novel dendritic cell-like subset of CD64(+) / CD16(+) blood monocytes.

Human monocytes (Mo) consist of a major subset of Fcgamma-receptor I (CD64)-positive typical low accessory phagocytes, and a minor CD64(-) DC-like subset with high T cell-accessory and IFN-alpha-releasing activity. Both populations also differentially express CD16 (Fcgamma-receptor III). Double labeling with anti-CD64 and anti-CD16 mAb, as performed here, identified four different subsets.