Myeloid derived suppressor cells rat

Background: Programmed death-ligand 1 (PD-L1) is a critical immune checkpoint molecule which promotes immunosuppression by binding to PD-1 on T-cells in tumor immunity. We have previously identified that activation of toll like receptor 4 (TLR-4), which serves an important role in the induction of antitumor immune response during Bacillus Calmette-Guérin (BCG) immunotherapy, could upregulate PD-L1 expression in bladder cancer (BCa) cells through the classical mitogen-activated protein kinase (MAPK) pathway and subsequently weaken the cytotoxicity of cytotoxic T lymphocyte (CTL)...

AIM: To test whether a delayed and short course of rapamycin would induce immunosuppressive effects following allogeneic orthotopic liver transplantation (OLT) in rats. METHODS: Allogeneic OLTs were performed using Dark Agouti livers transplanted into Lewis recipients, and syngeneic OLTs were performed using the Lewis rat strain. Rapamycin (1 mg/kg per day) was administered by gavage from day 4 to day 11 post-transplantation. Lymphocyte cellular compartments were analyzed by flow cytometry in draining lymph nodes, non-draining lymph nodes and the spleen at days 11 and 42 in rapamycin-treated rats, untreated control rats and syngeneic grafted rats...

Staphylococcus aureus (S. aureus) is one of the most common causes of biofilm infections in periprosthetic joint infections (PJIs). Accumulating evidence has shown that the immunosuppressive environment established by S. aureus biofilm infection in PJIs involves the presence of myeloid-derived suppressor cells (MDSCs) and M2-macrophages. Due to the diversity of MDSCs, little is known about whether S. aureus biofilm preferentially expands specific MDSC subsets or whether MDSCs can further differentiate into M2-macrophages during S...

Hemoglobin vesicles (HbVs) are oxygen carriers consisting of Hb molecules and liposome in which human hemoglobin (Hb) molecules are encapsulated. Investigations of HbV biocompatibility have shown that HbVs have no significant effect on either the quality or quantity of blood components such as RBC, WBC, platelets, complements, or coagulation factors, reflecting its excellent biocompatibility. However, their effects on the immune system remain to be evaluated. HbVs might affect the function of macrophages because they accumulate in the reticuloendothelial system...

Acute myeloid leukemia (AML) is a heterogeneous malignant disorder derived from the myeloid hematopoietic cells that accounts for ~80% of all adult acute leukemia. Numerous studies have shown that drug resistance not only exists against conventional chemotherapeutic drugs, but also limits the efficacy of new biological agents. Therefore, it is important to identify the mechanisms behind chemoresistance and seek therapeutic strategies to enhance efficacy in AML chemotherapy. MicroRNA (miR)-217 has been recognized as a tumor suppressor that is downregulated in various types of cancer, however the mechanisms behind the expression and function of miR-217 in AML have not yet been recognized...

CONTEXT: Myeloid-derived suppressor cells (MDSCs) are a subset of immature myeloid cells that function as immunosuppressive cells in various pathological conditions. Membrane-derived microvesicles are thought to be involved in MDSC induction. Earlier reports have described that injection of considerable amount of liposome into rat can suppress Con A-induced splenic T-cell proliferation. Liposome-internalized cells expressing CD11b/c suppress T-cell proliferation. Nitric oxide (NO) appears to be involved in the suppression...

AIMS: Partial bladder outlet obstruction (PBOO) causes tissue inflammation, a significant increase in markers of systemic oxidative stress, and proliferation of circulating myeloid-derived suppressor cells. Here, we investigated the regulatory mechanisms underlying inflammation and helper T cell involvement in PBOO. METHODS: Surgical PBOO was performed in four groups of rats: control (C), obstruction at 2 (O2) and 4 (O4) weeks, and 4 weeks after the relief of PBOO (R4) (n = 6 each)...

BACKGROUND: The asbestos-like toxicity of some engineered carbon nanotubes (CNT), notably their capacity to induce mesothelioma, is a serious cause of concern for public health. Here we show that carcinogenic CNT induce an early and sustained immunosuppressive response characterized by the accumulation of monocytic Myeloid Derived Suppressor Cells (M-MDSC) that counteract effective immune surveillance of tumor cells. METHODS: Wistar rats and C57BL/6 mice were intraperitoneally injected with carcinogenic multi-walled Mitsui-7 CNT (CNT-7) or crocidolite asbestos...

Malignant gliomas are resistant to natural killer (NK) cell immune surveillance. However, the mechanisms used by these cancers to suppress antitumor NK cell activity remain poorly understood. We have recently reported on a novel mechanism of innate immune evasion characterized by the overexpression of the carbohydrate-binding protein galectin-1 by both mouse and rat malignant glioma. Here, we investigate the cytokine profile of galectin-1-deficient GL26 cells and describe the process by which these tumors are targeted by the early innate immune system in RAG1(-/-) and C57BL/6J mice...

We investigated the influence of different fluid resuscitation techniques on the number of myeloid-derived suppressor cells (MDSCs) in rats. Seventy-two healthy Sprague-Dawley rats were randomly divided into groups that received sham operation (Sham group), hypertonic saline (HRS group), lactated ringer's solution (LRS group), or crystalloid solution (LCRS group). Six rats from each group were sacrificed by cervical dislocation at 12, 24, and 48 h after resuscitation. The spleens were harvested under sterile conditions and spleen cell suspension was prepared...

Dental pulp is a dynamic tissue able to resist external irritation during tooth decay by using immunocompetent cells involved in innate and adaptive responses. To better understand the immune response of pulp toward gram-negative bacteria, we analyzed biological mediators and immunocompetent cells in rat incisor pulp experimentally inflamed by either lipopolysaccharide (LPS) or saline solution (phosphate-buffered saline [PBS]). Untreated teeth were used as control. Expression of pro- and anti-inflammatory cytokines, chemokine ligands, growth factors, and enzymes were evaluated at the transcript level, and the recruitment of the different leukocytes in pulp was measured by fluorescence-activated cell-sorting analysis after 3 h, 9 h, and 3 d post-PBS or post-LPS treatment...

Circulating fibrocytes were reported to represent a novel myeloid-derived suppressor cell (MDSC) subset and they were also proposed to be involved in the tumor immune escape. This novel fibrocyte subset had a surface phenotype resembling non-monocytic MDSCs (CD14 - CD11c hi CD123 - ) and exhibited immunomodulatory roles. Most effector functions of fibrocytes (circulating fibroblast-progenitors) are accomplished as tissue fibroblasts, likewise in the tumor microenvironment. Therefore, fibroblasts at tumor tissues should be evaluated whether they display similar molecular/gene expression patterns and functional roles to the blood-borne fibrocytes...

Limited knowledge is available on myeloid derived suppressor cells (MDSCs) of rat origin. We examined the myeloid cells from peripheral blood, bone marrow and spleens of healthy and mammary tumor bearing rats employing a novel immunophenotyping strategy with CD172a, HIS48, and Rp-1 antibodies. We addressed rat granulocytes by Rp-1 positivity and used HIS48 in discrimination of two mononuclear cell subsets. An expansion of granulocyte numbers was detected in peripheral blood and spleens of mammary tumor-bearing animals...

UNLABELLED: Tumors recruit and reprogram immune cells to support tumor development and spread, the most prominent among them being of monocytic origin such as tumor-associated macrophages (TAM) or myeloid-derived suppressor cells (MDSC). The alarmin S100A8/A9 has been implicated in the induction of TAM and MDSC. We assessed S100A9 as a molecular imaging marker for the activity of tumor-associated immune cells in a syngeneic murine breast cancer model. S100A9 could serve as a surrogate marker for tumor immune crosstalk as a function of malignancy, providing a tool with the potential for both basic research in tumor immunology and clinical stratification of patients...

Chronic inflammation is a risk factor for several different cancers including colorectal cancer (CRC). However, the mechanisms underlying the contribution of inflammation to cancer remain elusive. Pro-inflammatory mediators such as cyclooxygenase 2 (COX-2) and prostaglandin E2 (PGE2) contribute to cancer progression. Here, we show that COX-2 is an immediate-early response gene induced by growth factors and pro-inflammatory cytokines and its levels are elevated in human CRCs. Furthermore, we show that COX-2-derived PGE2 promotes colonic tumor growth via silencing certain tumor suppressors and DNA repair genes by DNA methylation in colonic epithelial tumor cells...

PURPOSE: Partial bladder outlet obstruction causes a significant increase in tissue and systemic oxidative stress markers and tissue inflammatory cytokine levels. Myeloid-derived suppressor cells, IFN-γ, IL-10 and aldosterone are believed to be associated with oxidative stress and inflammation. We investigated alterations in plasma myeloid-derived suppressor cells, IFN-γ, IL-10 and aldosterone levels in partial bladder outlet obstruction and after its reversal. MATERIALS AND METHODS: Rats with surgically induced partial bladder outlet obstruction were divided into 4 groups of 3 each, including sham treated, 4-week obstruction, and 4 and 8-week obstruction with relief...

Previous studies have shown that the antitumor effects of OX40 agonists depend on the immunogenicity of the tumor and that poorly immunogenic tumors such as B16F10 melanomas do not respond to OX40 agonist treatment. In this study, we have shown that intratumoral CD4+ T lymphodepletion sensitized poorly immunogenic B16F10 melanomas to immunotherapy with an OX40 agonist. CD4+ T lymphodepletion dramatically altered the tumor immune microenvironment, making it more susceptible to the antitumor effects of an OX40 agonist by enhancing the accumulation of CD8+ T cells and natural killer (NK) cells in tumor tissue...

Regulatory myeloid cells (RMC) are emerging as novel targets for immunosuppressive (IS) agents and hold considerable promise as cellular therapeutic agents. Herein, we discuss the ability of regulatory macrophages, regulatory dendritic cells, and myeloid-derived suppressor cells to regulate alloimmunity, their potential as cellular therapeutic agents, and the IS agents that target their function. We consider protocols for the generation of RMC and the selection of donor- or recipient-derived cells for adoptive cell therapy...

BACKGROUND: Hemorrhagic shock is usually associated with complicated immune and inflammatory responses, which are sometimes crucial for the prognosis. As regulators of the immune and inflammatory system; proliferation, migration, distribution and activation of myeloid-derived suppressor cells (MDSCs) are intimately linked to the inflammation cascade. METHODS: In a model of severe hemorrhagic shock, thirty-five rats were randomly divided into control, sham, normal saline resuscitation (NS), hypertonic saline resuscitation (HTS), and hydroxyethyl starch resuscitation (HES), with seven in each group...

Pneumocystis pneumonia (PcP) develops in immunocompromised patients. Alveolar macrophages play a key role in the recognition, phagocytosis, and degradation of Pneumocystis, but their number is decreased in PcP. Our study of various inflammatory components during PcP found that myeloid-derived suppressor cells (MDSCs) accumulate in the lungs of mice and rats with Pneumocystis pneumonia (PcP). We hypothesized that treatment with all-trans retinoic acid (ATRA), a metabolite of vitamin A, may effectively control Pneumocystis (Pc) infection by inducing MDSCs to differentiate to AMs...