Regulatory T cells (Treg) represent one of the most important mechanisms of immunoregulation. Treg suppress immune reactions and prevent overactivation of the immune system. There is a lot of ways of Treg action described, here we have focused on Treg interference with macrophages. The suppressor capacity of a highly purified Treg population was demonstrated in proliferation assays. The level of suppression of effector T cell proliferation differs depending on the presence of macrophages in the culture. Treg suppression has been significantly higher in the presence of macrophages. These observations led to hypotesis that Treg affect directly macrophages. However, using flow cytometry, reduction of expression of costimulatory molecules on macrophages after culture with Treg was not observed. Macrophages precultured with Treg showed a comparable functionality as macrophages cultured alone. Neither flow cytometry nor live cell imaging revealed any cytotoxic activity of Treg towards macrophages. Despite the presence of macrophages, Treg did not suppress effector cell proliferation in a model, where stronger activation of effector cells was induced. Therefore, a new hypothesis was presented - initially observed higher suppression in the presence of macrophages was probably caused by a qualitatively or...

(ENGLISH) Background: The investigation of the immunosuppression usage in cardiovascular surgery and interventional cardiology is, at present, concentrated on three main topics: 1) influence on intimal hyperplasia of coronary and peripheral vascular reconstructions 2) influence on rejection of allogeneic vascular grafts and 3) influence on intimal hyperplasia of coronary arteries after endovascular interventions. Modern immunosuppressive drug FK506 (Tacrolimus) could have a positive effect for these indications. In experimental study, FK506 inhibited rejection of arterial allografts and also inhibited intimal hyperplasia in percutaneous coronary interventions. Aims: The purpose of this study was to evaluate the effect of systemic tacrolimus treatment on the process of arterialisation of allogeneic and syngeneic venous grafts in a rat vein-to-artery implantation model. Material and Methods: Lewis (LEW) rats were used as recipients of syngeneic (Lewis) or allogeneic (Brown-Norway; BN) iliolumbar veins which were implanted into abdominal aorta. Recipients were divided into six groups. In groups A, E and F were animals after syngeneic (LEW to LEW) and in groups B, C and D were animals after allogeneic (BN to LEW) transplantations. Animals in the groups C and F had daily intramuscular injections of...

Objective: Stress, either physical or psychological, can modulate immune function. However, the mechanisms associated with stress-induced immune suppression remain to be elucidated. β-Arrestin 2 serves as adaptor, scaffold, and/or signal transducer. The role of β-arrestin 2 in stress-induced immune suppression is not known yet. Methods/Results: Here, we demonstrate that β-arrestin 2 deficiency in mice increases the sensitivity to the chronic stress-induced reduction in the number of splenocytes. Interestingly, the stress-induced suppression of T helper-type (Th) 1 cytokines and the increased production of Th2 cytokines were greatly enhanced in β-arrestin 2-deficient mice compared with wild-type mice. Moreover, inhibition of PI3K in β-arrestin 2-deficient mice exerts an additive effect on the stress-induced reduction in the number of splenocytes. Conclusion: Our study demonstrates that a deficiency in β-arrestin 2 augments stress-induced immune suppression.

Background microRNA-23b (miR-23b) is a multiple functional miRNA. We hypothesize that miR-23b plays a role in the pathogenesis of sepsis. Our study investigated the effect of miR-23b on sepsis-induced immunosuppression. Methods Mice were treated with miR-23b inhibitors by tail vein injection 2 days after cecal ligation puncture (CLP)-induced sepsis. Apoptosis in spleens and apoptotic signals were investigated, and survival was monitored. T-cell immunoreactivities were examined during late sepsis. Nuclear factor B (NF-B)-inducing kinase (NIK), tumor necrosis factor (TNF)-receptor associated factor 1 (TRAF1), and X-linked inhibitor of apoptosis protein (XIAP), the putative targets of miR-23b, were identified by a dual-luciferase reporter assay. Results miR-23b expression is upregulated and sustained during sepsis. The activation of the TLR4/TLR9/p38 MAPK/STAT3 signal pathway contributes to the production of miR-23b in CLP-induced sepsis. miR-23b inhibitor decreased the number of spleen cells positive by terminal deoxynucleotidyl transferase dUTP nick-end labeling and improved survival. miR-23b inhibitor restored the immunoreactivity by alleviating the development of T-cell exhaustion and producing smaller amounts of immunosuppressive interleukin 10 and interleukin 4 during late sepsis. We demonstrated that miR-23b mediated immunosuppression during late sepsis by inhibiting the noncanonical NF-B signal and promoting the proapoptotic signal pathway by targeting NIK, TRAF1, and XIAP. Conclusions Inhibition of miR-23b reduces late-sepsis-induced immunosuppression and improves survival. miR-23b might be a target for immunosuppression.

No description available.

Cyclosporine and prednisone are immunosuppressive drugs that are commonly used in combination for the treatment of immune-mediated diseases, and have been shown to individually cause significant suppression of IL-2. Currently, no studies have been performed to determine how a combination of the two drugs would impact suppression of IL-2, and if an additive or synergistic effect on cytokine production could be demonstrated, as in studies of other species. An additive effect of immunosuppression associated with this drug combination could allow clinicians to decrease dosages of drugs, thereby reducing drug costs and minimizing adverse drug side effects. In a cross-over study design using six healthy dogs, the expression of IL-2 was affected with administration of cyclosporine, prednisone, or a combination of each drug. However, there was no significant difference in the level of immunosuppression compared to cyclosporine alone. Small sample size and the dosages of each drug used potentially affected the strength of the results.

Indiana University-Purdue University Indianapolis (IUPUI) / More than 200,000 American women are diagnosed with breast cancer each year. Although therapies effective in treating metastatic breast cancer currently exist, each year approximately 40,000 women die from this disease. Current evidence indicates that anti-cancer immune responses can be induced by vaccination in situ to the growth of metastasis and protect patients from the tumor recurrence. However, induction of anticancer immune responses may be limited in their efficacy due to immune suppression mechanisms induced by the developing cancer. Myeloid-derived suppressor cells are one population of immune regulators comprised of immature cells of myeloid origin with important roles in blocking immune activation and promoting tumor progression. Elimination or maturation of these cells has been found to promote enhanced anti-tumor effects and improve overall survival. This thesis identifies a new role for interleukin-12 as a modulator of myeloid-derived suppressor cell activity. Interleukin-12 was found to promote up-regulation of cell maturation markers on the surface of myeloid-derived suppressor cells with an accompanying decrease in factors responsible for conferring suppressive activity such as nitric oxide synthase 2 and arginase I. The alterations in myeloid-derived suppressor cells were observed following both in vitro and in vivo treatment with interleukin-12. Further analysis of the anti-tumor efficacy of interleukin-12 revealed that at least part of its suppression of tumor growth can be linked to reductions in myeloid-derived suppressor cell populations in the tumor microenvironment and an influx of active CD8+ T cells into the tumor microenvironment. The findings outlined in this thesis show that interleukin-12 alters the suppressive function of myeloid-derived suppressor cells leading to significant immune infiltration and activation resulting in increased overall survival and a reduction in metastasis.

Myeloid-derived suppressor cells (MDSC) expand during sepsis, suppress both innate and adaptive immunity, and promote chronic immunosuppression, which characterizes the late/chronic phase of sepsis. We previously reported that the transcription factors Stat3 and C/EBPb synergize to induces the expression of microRNA (miR)-21 and miR-181b to promote MDSC expansion in a mouse model of polymicrobial sepsis that progresses from an early/acute proinflammatory phase to a late/chronic immunosuppressive stage. We also showed that Gr1+CD11b+ cells, the precursors of MDSCs, from mice genetically deficient in the inflammatory protein S100A9 lack miR-21 or miR-181b in late sepsis, and are not immunosuppressive. In the present study, we show that S100A9 induces miR-21 and miR-181b during the late sepsis phase. We find that S100A9 associates with and stabilizes the Stat3-C/EBPb protein complex that activates the miRNA promoters. Reconstituting Gr1+CD11b+ cells from the S100A9 knockout mice with late sepsis with S100A9 protein restores the Stat3-C/EBPb protein complex and miRNA expressions, and switches the Gr1+CD11b+ cells into the immunosuppressive, MDSC phenotype. Importantly, we find that this process requires IL-10 mediated signaling, which induces S100A9 translocation from the cytosol to the nucleus. These results demonstrate that S100A9 promotes MDSC expansion and immunosuppression in late/chronic sepsis by inducing the expression of miR-21 and miR-181b.

Large granular lymphocyte leukemia (LGLL) represents a rare group of diseases with considerable difficulties in their correct diagnostic workup and therapy. The major challenges lie in their distinction from reactive (including autoimmune) lymphoproliferations. Moreover, monoclonal LGL proliferative diseases are in fact a heterogeneous group of disorders, as recognized by the three subtypes in the current WHO classification. It distinguishes two chronic forms (the focus of this case series), namely T-LGLL and chronic lymphoproliferative disorders of Natural Killer cells (CLPD-NK) as well as aggressive NK-cell leukemia. In the clinical routine, the variable presentations and phenotypes of T-LGLL and CLPD-NK are underappreciated. The relevant differential diagnoses range from benign reactive T-cell expansions to other mature T-cell leukemias to highly aggressive gd-lymphomas. T-LGLL or CLPD-NK patients suffer from a wide variety of symptoms often including, but not limited to, cytopenias or classical autoimmune phenomena. They receive treatments ranging from mere supportive measures (e.g. antibiotics, growth factors, transfusions) over strategies of immunosuppression up to anti-leukemic therapies. The diagnostic pitfalls range from recognition of the subtle T-cell proliferation, repeated establishment of monoclonality, assignment to a descript immunophenotypic pattern, and interpretations of molecular aberrancies. Here, we report a series of selected cases to represent the spectrum of LGLL. The purpose is to raise awareness among the scientifically or practically interested readers of the wide variety of clinical, immunological, and phenotypic features of the various forms of LGLL, e.g. of T-cell type, including its gd forms or those of NK-lineage. We highlight the characteristics and courses of four unique cases from two academic centers, including those from a prospective nationwide LGLL registry. Each case of this instructive catalogue serves to transport a key message from the areas of (chronic inflammatory) contexts in which LGLL can arise as well as from the fields of differential diagnostics and of various treatment options. Implications for optimization in these areas are discussed.

(1) Background: No information is available on how dogs with hypothyroidism (HypoT) respond to vaccination. This study measured pre- and post-vaccination anti-canine parvovirus (CPV) antibodies in dogs with HypoT treated with levothyroxine and compared the results to those of healthy dogs. (2) Methods: Six dogs with HypoT and healthy age-matched control dogs (n = 23) were vaccinated against CPV with a modified-live vaccine. Hemagglutination inhibition was used to measure antibodies on days 0, 7, and 28. The comparison of the vaccination response of dogs with HypoT and healthy dogs were performed with univariate analysis. (3) Results: Pre-vaccination antibodies (≥10) were detected in 100% of dogs with HypoT (6/6; 95% CI: 55.7–100) and in 100% of healthy dogs (23/23; 95% CI: 83.1–100.0). A ≥4-fold titer increase was observed in none of the dogs with HypoT and in 4.3% of the healthy dogs (1/23; CI95%: <0.01–22.7). Mild vaccine-associated adverse events (VAAEs) were detected in 33.3% of the dogs with HypoT (2/6; 95% CI: 9.3–70.4) and in 43.5% (10/23; 95% CI: 25.6–63.2) of the healthy dogs. (4) Conclusions: There was neither a significant difference in the dogs’ pre-vaccination antibodies (p = 1.000), or vaccination response (p = 0.735), nor in the occurrence of post-vaccination VAAEs (p = 0.798). The vaccination response in dogs with levothyroxine-treated HypoT seems to be similar to that of healthy dogs.