Percentage Of Dendritic Cells Research Articles

Cellular Composition of Rat Thymus with Combined Effects of Carcinogen and Stress

The aim of the research was study the effects of experimental breast cancer and stress on the thymus of laboratory animals Material and methods . Thymus 40 white nonlinear female rats of the same age were investigated using luminescent-histochemical, general histological and immunohistochemical methods . The animals were divided into 3 groups. In the 1st group were intact animals. Rats of the 2nd group were injected with N-methyl-N-nitrosourea, causing breast cancer. Animals of the 3rd group experienced a combined effect of carcinogen and water-immobilization stress. Results. It was established that the administration of N-methyl-N-nitrosourea to female rats causes an increase in the size of the medullar and cortex of the thymus lobes. In cells of the premedullary and subcapsular zones, an increase in the level of serotonin and catecholamines is observed, and in cells of the premedullary zone, in the thymocytes of the cortex and medulla - a decrease in the level of histamine. The ratio (serotonin + histamine) / catecholamines decreases and the percentage of degranulated mast cells increases. Also, the number of mature T-lymphocytes and macrophages is increasing against the background of a decrease in the number of S-100+ cells. Combined effect of factors revealed a decrease in the size of the lobes of the organ, the replacement of the parenchyma with adipose and connective tissue, an increase in the content of serotonin and catecholamines, a significant decrease in histamine levels, with a decrease in the ratio (serotonin + histamine) / catecholamines in the same cells, an increase in mature forms of T-lymphocytes and macrophages, as well as a decrease in the percentage of dendritic cells. Conclusion. The combined effect causes a more pronounced disorganization of the morphofunctional state of the thymus and leads to the 4th phase of the accidental involution of the thymus with the development of atrophy and sclerosis of the organ.

Cationic Nanoliposomes Are Efficiently Taken up by Alveolar Macrophages but Have Little Access to Dendritic Cells and Interstitial Macrophages in the Normal and CpG-Stimulated Lungs.

The purpose of this study was to assess whether cationic nanoliposomes could address tumor vaccines to dendritic cells in the lungs in vivo. Nanoliposomes were prepared using a cationic lipid, dimethylaminoethanecarbamoyl-cholesterol (DC-cholesterol) or dioleoyltrimethylammoniumpropane (DOTAP), and dipalmitoylphosphatidylcholine (DPPC), the most abundant phospholipid in lung surfactant. The liposomes presented a size below 175 nm and they effectively entrapped tumor antigens, an oligodeoxynucletotide containing CpG motifs (CpG) and the fluorescent dye calcein used as a tracer. Although the liposomes could permanently entrap a large fraction of the actives, they could not sustain their release in vitro. Liposomes made of DOTAP were safe to respiratory cells in vitro, while liposomes composed of DC-cholesterol were cytotoxic. DOTAP nanoliposomes were mainly taken up by alveolar macrophages following delivery to the lungs in mice. Few dendritic cells took up the liposomes, and interstitial macrophages did not take up liposomal calcein more than they took up soluble calcein. Stimulation of the innate immune system using liposomal CpG strongly enhanced uptake of calcein liposomes by all phagocytes in the lungs. Although a small percentage of dendritic cells took up the nanoliposomes, alveolar macrophages represented a major barrier to dendritic cell access in the lungs.

Methadone therapy modulate the dendritic cells of heroin addicts

Evidence from various studies suggests that narcotics abuse may exert adverse immunomodulatory effects on immune responses. The aim of this research was to understand the effects of detoxification with methadone on the percentage of dendritic cells (DCs) and expression of its markers in heroin addicts. In this study, myeloid DCs (CD11c+) and plasmacytoid DCs (CD123+) were examined in two groups. These groups comprised of 20 healthy volunteers and 20 chronic heroin addicts, before and after detoxification with methadone. The percentages of myeloid DCs and plasmacytoid DCs were lower in addict subjects than in the control. The HLA-DR expression on DCs was significantly lower in addict subjects than in the control, whereas CD11c and CD123 expression in DCs subsets were increased in them. Most of these changes were modified after the methadone therapy. Dendritic cells are essential to the initiation of primary immune responses, therefore the disruption of their function can be one of the reasons for the increased prevalence of infections in heroin addicts. The methadone therapy can improve the imposed changes by heroin.

P109 Preliminary identification of immune cells in the perfusate of renal allografts undergoing hypothermic machine perfusion

Aim Renal allografts stored with hypothermic machine perfusion (HPM) have improved outcomes compared to static methods. Passenger immune cells from the allograft have been implicated in acute rejection; improved outcomes with HPM may be due to cell removal by the pump. This study aimed to identify passenger immune cells present in the perfusate of HPM-preserved allografts. Once characterized, future strategies to suppress these cells may prevent acute rejection and improve graft survival. Methods All kidneys placed on HPM prior to transplant from May 2016 to August 2017 were eligible. Perfusate fluid was analyzed using flow cytometry for immune cells and information about the donors was collected. Wilcoxon Scores and Spearman Correlation Coefficient were used in statistical analysis. Results Twenty-seven perfusate specimens were analyzed. Selected donor characteristics: 63.6% male, 36.4% female; 63.6% donation after cardiac death; 54.5% pre-procurement transfusion. The mean HPM and cold ischemia times (CIT) were 9.9 h and 13.9 h respectively, and mean KDPI 36%. Flow cytometry showed a heterogeneous mix of immune cell types in the perfusate, similar to blood. CD15+ granulocytes, CD14+ monocytes, and CD8+ T cells were predominant in the perfusate. Dendritic and natural killer (NK) cells in perfusate were more abundant compared to blood. Conclusions Passenger immune cells, specifically dendritic cells have been implicated in acute rejection. This study showed the perfusate of renal allografts contains an array of immune cells, with a significantly higher percentage of dendritic cells and NK cells, as compared to blood. Future studies would show if HPM removal of these immune cells accounts for improved outcomes. ∗Frequencies of Cell Types in Human Peripheral Blood, www.stemcell.com .

Blockade of Tyrosine Kinases as Preventive Strategy Against Cardiac Allograft Vasculopathy in a Murine Aortic Transplant Model

Objectives Previous reports suggest a role of platelet derived growth factor (PDGF) in the development of cardiac allograft vasculopathy (CAV). The pharmaceutical blockade of tyrosine kinases may alter the expression of different growth factor receptors: platelet derived growth factor (PDGF), vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) and hereby play a role in the context of cardiac allograft vasculopathy. Therefore the aim of this study was to determine the impact of tyrosine kinase inhibition on the development of cardiac allograft vasculopathy in a mouse model. Methods Fully allogeneic mouse aortas from C57BL/6 mice (H2b) were abdominally transplanted into CBA mice (H2k). Recipients were treated with tyrosine kinase inhibitor nintedanib (60mg/kg/d) and sacrificed on day 14 for cytokine PCR analysis of the graft or on day 30 for (immuno-) histological measurements. Results Aortic grafts treated with tyrosine kinase inhibitor nintedanib showed significantly reduced neointima proliferation (33% ± 12% vs. 54% ± 13%) after 30 days. These findings go along with significantly reduced amounts of smooth muscle cells (SMC) (20% ± 9% vs. 42% ± 10%) within the neointima. Further immunofluorescence analysis revealed no relevant difference in the percentages of dendritic cells, macrophages and CD4+ T-cells within the neointima. Meanwhile, the expression of both PDGF receptor subtypes α and β was reduced within the neointima of the aortic grafts. Additionally, we found a reduced gene expression of the ligand PDGF-B, a mitogen for SMC, and of the pro-inflammatory CD40L. Conclusion PDGF receptor blockade via inhibition of receptor tyrosine kinases seems to be a promising way to prevent the development of cardiac allograft vasculopathy in a mouse model. We would speculate a direct inhibition of the migration and proliferation of smooth muscle cells with a resulting decrease of neointima formation as the mechanism of action.

Kinetics of intratumoral T-cell activation during chemoradiation for cervical cancer.

6 Background: Limited data in cancer patients have suggested that chemotherapy and radiation impact local and systemic immune cell populations. Radiation therapy (RT) is known to deplete circulating lymphocytes but is thought to increase local antigen presentation. The dynamics of these competing effects on the kinetics of intratumoral infiltration and expansion of activated and immunoregulatory T cells are unknown. Methods: We prospectively evaluated intratumoral immune infiltration during fractionated RT using multi-spectral flow cytometry. Cervical brushings were obtained from 14 patients before (baseline) and during RT (week 1, 3 and 5). Cells collected from the cervical brushings were stained with a 16-color panel of antibodies that included markers to identify T cell and dendritic cell subsets with activation and suppressor molecules. Changes in immune cell subsets at different time points were evaluated and calculated using matched-pair analysis with Wilcoxon rank sum test. Results: CD3+ T cells declined over the first week of treatment (28% of CD3 at baseline, vs. 14.8% at week 1, p = 0.0273). The percentage of CD3+ cells subsequently increased at 3 weeks (25.6%) and 5 weeks (37.8%). Both CD8+ and CD4+ T cells underwent a decline at week 1 followed by expansion at week 3 and 5. Percentages of regulatory T cells (CD4+Foxp3+) showed a similar trend of reduction and further expansion but did not reach significance. The percentage of CD8+ T cells expressing the T cell activation marker CD69 and the cytotoxic protease Granzyme B (GrzB) continuously increased over time (CD69+: 11.8%, 27.7%, 38.7%, 57.5%, and GrzB+: 23.9%, 53.2%, 48.1%, 58.2%). While the percentage of dendritic cells (CD11c+ CD11b+) was stable during treatment, the subset of activated dendritic cells expressing CD86 increased at week 1 and subsequently declined (week 1, 19.1% vs week 5, 9.8%, p = 0.0642). Conclusions: Activated CD8+ effector T cells expand in the cervix during radiation therapy. Moreover, in the first week of treatment, CD8+ T cells contract while dendritic cells undergo activation suggesting this may be a critical time to intervene to maximize anti-tumor immunity.

Усиление иммуногенности вируса гриппа A путем подавления иммуносупрессорной функции белка NS1

Укорочение неструктурного белка NS1 является перспективным методом создания аттенуированных высокоиммуногенных вирусов гриппа. Однако механизмы врожденного иммунитета, обуславливающие повышенную иммуногенность штаммов с модифицированным NS1 в настоящее время изучены недостаточно. Целью данной работы было сравнение продукции цитокинов, динамики изменения популяционного состава клеток врожденного иммунитета и уровня адаптивного Т-клеточного иммунного ответа после иммунизации мышей двумя вариантами вируса гриппа А/Puerto Rico/8/1934 (A/PR8): вирусом дикого типа А/PR8/full NS и вирусом с укороченным до 124 аминокислотных остатков белком NS1 (А/PR8/NS124). В данном исследовании для компенсации различий в репродуктивной активности исследуемых штаммов в респираторном тракте был выбран интраперитонеальный способ введения вирусов. Уровень интерферона β (IFNβ), фактора некроза опухолей α (TNFα), моноцитарного хемоаттрактантного белка 1 (MCP1), интерлейкина 6 (IL6) и IL27 в перитонеальных смывах мышей, иммунизированных А/PR8/NS124, был существенно выше, чем в группе, получившей А/PR8/full NS. В то же время группа А/PR8/NS124 характеризовалась замедленным привлечением моноцитов и нейтрофилов в перитонеальную полость и более выраженным снижением относительного содержания дендритных клеток по сравне-нию с А/PR8/full NS. Важно, что уровень экспрессии активационного маркера CD86 на клетках, экспрессирующих молекулы главного комплекса гистосовместимости II (MHCII+) перитонеальной полости мышей, иммунизированных штаммом А/PR8/NS124, имел более высокие значения по сравнению с группой А/PR8/full NS. Анализ адаптивного иммунного ответа показал, что иммунизация штаммом А/PR8/NS124 приводит к формированию повышенного содержания вирус-специфических CD8+-эффекторных Т-лимфоцитов, характеризующихся одновременной продукцией IFNγ, IL2 и TNFα. Мы предполагаем, что повышенная продукция цитокинов, усиленная миграция дендритных клеток, а также сохранение высокого уровня экспрессии CD86 на антигенпрезентирующих клетках (АПК) мышей через 24 ч после иммунизации штаммом А/PR8/NS124 приводит к более эффективной презентации антигенов вируса гриппа и, как следствие, к усилению вирусспецифического Т-клеточного иммунного ответа.

Enhancement of the immunogenicity of influenza A virus by the inhibition of immunosuppressive function of NS1 protein

ABSTRACT The truncation of the nonstructural NS1 protein is a novel approach for the generation of immunogenic attenuated influenza viruses. However, the innate immune mechanisms that cause the increased immunogenicity of influenza viruses with altered NS1 proteins are poorly understood. The goal of this study was to compare the immune responses in mice immunized with two variants of the influenza A/Puerto Rico/8/1934 (A/PR8) virus: the wild type virus (A/PR8/full NS) and the variant with the NS1 protein shortened to 124 amino acid residues (A/PR8/NS124). The investigated parameters of immunity included cytokine production, the dynamic variation of the innate immune cell populations, and the rate of the influenza-specific T-cell responses. An intraperitoneal route of immunization was chosen due to the variability in the replication capacity of the investigated viruses in the respiratory tract. The levels of interferon β (IFNβ), tumor necrosis factor α (TNFα), monocyte chemo-attractant protein 1 (MCP1), interleukin 6 (IL6), and IL27 in peritoneal washings of mice immunized with A/PR8/NS124 were significantly higher compared to the mice immunized with the wild-type virus. The A/PR8/NS124 treated group showed a delayed attraction of monocytes and neutrophils as well as a more pronounced reduction in the percentage of dendritic cells in the peritoneal cavity. The expression level of the CD86 activation marker on the cells expressing the molecules of the major histocompatibility complex II (MHCII+) was significantly higher in mice immunized with A/PR8/NS124 than in the group immunized with A/PR8/full NS. Finally, immunization with A/PR8/NS124 led to an increased formation of influenza-specific CD8+ effector T-cells characterized by the simultaneous production of IFNγ, IL2, and TNFα. We hypothesize that elevated cytokine production, enhanced dendritic cell migration, and increased CD86 expression on antigen-presenting cells upon immunization with A/PR8/NS124 lead to a more effective presentation of viral antigens and, therefore, promote an increased antigen-specific CD8+ immune response.

Toll-Like Receptor 4 Is Essential for the Expression of Sphingosine-1-Phosphate-Dependent Asthma-Like Disease in Mice.

Sphingosine-1-phosphate (S1P) levels significantly increase in bronchoalveolar lavage (BAL) of asthmatic patients following segmental allergen challenge and this increase well correlates with pulmonary inflammation. Epidemiological, genetic, clinical, and experimental data indicate a potential for the toll-like receptor 4 (TLR4) to initiate and exacerbate allergic airway diseases. The aim of this study was to evaluate the contribution of TLR4 in S1P-dependent asthma-like disease in mice. BALB/c or TLR4 defective (C3H/HeJ) mice received S1P (10 ng/mouse), LPS (0.1 μg/mouse) or S1P + LPS. Furthermore, S1P-treated BALB/c mice were injected with the purified rabbit anti-TLR4 antibody (10 μg/mouse). S1P administration induced airway hyperreactivity and pulmonary inflammation associated to an increase in the percentage of dendritic cells (DCs) and macrophages into the lung of BALB/c mice. These effects were coupled to a reduction of DCs in the mediastinic lymph node. All these S1P-mediated effects were absent in TLR4 defective mice or reversed by treatment with a purified rabbit anti-TLR4 antibody. Confocal analysis of pulmonary sections showed a significant increase in TLR4+ cells and a similar presence of S1P1 and TLR4 following S1P challenge. Accordingly, the immunoprecipitation evidenced an increased S1P1/TLR4 interaction. In conclusion, our findings suggest that a functional interaction between S1P1 and TLR4 leads to an enhanced allergic inflammatory response. Thus, S1P pathway contributes to the sentinel role played by innate immunity providing new targets for prevention and treatment of allergic airway diseases.

Calreticulin Fragment 39-272 Promotes B16 Melanoma Malignancy through Myeloid-Derived Suppressor Cells In Vivo

Calreticulin (CRT), a multifunctional Ca2+-binding glycoprotein mainly located in the endoplasmic reticulum, is a tumor-associated antigen that has been shown to play protective roles in angiogenesis suppression and anti-tumor immunity. We previously reported that soluble CRT (sCRT) was functionally similar to heat shock proteins or damage-associated molecular patterns in terms of ability to activate myeloid cells and elicit strong inflammatory cytokine production. In the present study, B16 melanoma cell lines expressing recombinant CRT fragment 39-272 (sCRT/39-272) in secreted form (B16-CRT), or recombinant enhanced green fluorescence protein (rEGFP) (B16-EGFP), were constructed for investigation on the roles of sCRT in tumor development. When s.c. inoculated into C57BL/6 mice, the B16-CRT cells were significantly more aggressive (in terms of solid tumor growth rate) than B16-EGFP controls in a TLR4- and myeloid-derived suppressor cells (MDSC)-dependent manner. The B16-CRT-bearing mice showed increased Gr1+ MDSC infiltration in tumor tissues, accelerated proliferation of CD11b+Ly6G+Ly6Clow (G-MDSC) precursors in bone marrow, and higher percentages of G-MDSCs in spleen and blood, which was mirrored by decreased percentage of dendritic cells (DC) in periphery. In in vitro studies, recombinant sCRT/39-272 was able to promote migration and survival of tumor-derived MDSCs via interaction with TLR4, inhibit MDSC differentiation into DC, and also elicit expression of inflammatory proteins S100A8 and S100A9 which are essential for functional maturation and chemotactic migration of MDSCs. Our data provide solid evidence for CRT as a double-edged sword in tumor development.

Differential Immune Microenvironments and Response to Immune Checkpoint Blockade among Molecular Subtypes of Murine Medulloblastoma.

Despite significant strides in the identification and characterization of potential therapeutic targets for medulloblastoma, the role of the immune system and its interplay with the tumor microenvironment within these tumors are poorly understood. To address this, we adapted two syngeneic animal models of human Sonic Hedgehog (SHH)-driven and group 3 medulloblastoma for preclinical evaluation in immunocompetent C57BL/6 mice. Multicolor flow cytometric analyses were used to phenotype and characterize immune infiltrating cells within established cerebellar tumors. We observed significantly higher percentages of dendritic cells, infiltrating lymphocytes, myeloid-derived suppressor cells, and tumor-associated macrophages in murine SHH model tumors compared with group 3 tumors. However, murine group 3 tumors had higher percentages of CD8(+) PD-1(+) T cells within the CD3 population. PD-1 blockade conferred superior antitumor efficacy in animals bearing intracranial group 3 tumors compared with SHH group tumors, indicating that immunologic differences within the tumor microenvironment can be leveraged as potential targets to mediate antitumor efficacy. Further analysis of anti-PD-1 monoclonal antibody localization revealed binding to PD-1(+) peripheral T cells, but not tumor infiltrating lymphocytes within the brain tumor microenvironment. Peripheral PD-1 blockade additionally resulted in a marked increase in CD3(+) T cells within the tumor microenvironment. This is the first immunologic characterization of preclinical models of molecular subtypes of medulloblastoma and demonstration that response to immune checkpoint blockade differs across subtype classification. Our findings also suggest that effective anti-PD-1 blockade does not require that systemically administered antibodies penetrate the brain tumor microenvironment.

IMPS-25DIFFERENTIAL TUMOR MICROENVIRONMENTS AND RESPONSE TO IMMUNE CHECKPOINT BLOCKADE IN MOLECULAR SUBTYPES OF MURINE MEDULLOBLASTOMA

PURPOSE: Despite significant strides in the identification and characterization of potential therapeutic targets for medulloblastoma (MB), the role of the immune system and its interplay with the tumor microenvironment within these tumors are poorly understood. To address this, we adapted two syngeneic animal models of human Sonic Hedgehog (SHH)-driven and Group 3 MB for preclinical evaluation in immunocompetent C57BL/6 mice. METHODS AND RESULTS: Multicolor flow cytometric analyses were used to phenotype and characterize immune infiltrating cells within established cerebellar tumors. We observed significantly higher percentages of dendritic cells, infiltrating lymphocytes, myeloid derived suppressor cells and tumor-associated macrophages in murine SHH model tumors compared with Group 3 tumors. However, murine Group 3 tumors had higher percentages of CD8+ PD-1+ T cells within the CD3 population. PD-1 blockade conferred superior antitumor efficacy in animals bearing intracranial Group 3 tumors compared to SHH group tumors, indicating that immunologic differences within the tumor microenvironment can be leveraged as potential targets to mediate antitumor efficacy. CONCLUSIONS: This is the first immunologic characterization of preclinical models of molecular subtypes of MB, and demonstration that response to immune checkpoint blockade differs across subtype classification. Our findings provide strong evidence for distinct immunophenotypes across subtypes of MB that have important value in the clinical application of relevant immunotherapeutic strategies targeting MB.

Immunomodulatory activity of pidotimod administered with standard antibiotic therapy in children hospitalized for community-acquired pneumonia.

BackgroundSeveral attempts to improve immune function in young children have been made and encouraging results have been collected with pidotimod (PDT), a synthetic dipeptide molecule that seems to have immunomodulatory activity on both innate and adaptive responses. Until now, the effects of PDT on the immune system have only been studied in vivo after long-term administration to evaluate whether its immunomodulatory activity might prevent the development of infections. This study was planned to evaluate the immunomodulatory activity of PDT administered together with standard antibiotic therapy in children hospitalized for community-acquired pneumonia (CAP).MethodsA total of 20 children hospitalized for community-acquired pneumonia (CAP) were randomized at a 1:1 ratio to receive either standard antibiotics plus pidotimod (PDT) or standard antibiotics alone to evaluate the immunomodulatory activity of PDT. Blood samples for the evaluation of immunological parameters were drawn at the time of recruitment (T0) (i.e., before therapy administration), at T3 and T5 (i.e., 3 and 5 days after the initiation of therapy) as well as at T21 (i.e., 7 days after the therapy ended).ResultsFollowing pneumococcal polysaccharide stimulation, the percentage of dendritic cells (DCs) expressing activation and costimulatory molecules was significantly higher in children receiving PDT plus antibiotics than in the controls. A significant increase in tumor necrosis factor-α and/or interleukin-12 secretion and expression of toll like receptor 2 was observed in PDT-treated children compared with controls; this was followed by an increased release of proinflammatory cytokines by monocytes. In the PDT-treated group, mRNA expression of antimicrobial peptides and genes involved in the inflammatory response were also augmented in comparison with the controls.ConclusionsThese results demonstrate, for the first time, that PDT administered together with standard antibiotics is associated with a favorable persistent immunomodulatory effect in children with CAP.

Analysis of immune cell populations and cytokine profiles in murine splenocytes exposed to whole-body low-dose irradiation

Purpose: In contrast to high-dose therapeutic irradiation, definitive research detailing the physiological effects of low-dose irradiation is limited. Notably, the immunological response elicited after low-dose irradiation remains controversial.Materials and methods: Female C57BL/6 mice were whole- body-irradiated with a single or three daily fractions up to a total dose of 0.1, 1, or 10 cGy. Blood and spleen were harvested 2, 7 and 14 days after irradiation.Results: The splenic CD4+ T cell subpopulations were temporarily increased at 2 days after single or fractionated irradiation, whereas the percentage of dendritic cells (DC) and macrophages was decreased. Whereas CD8+ T cell populations were decreased in single-dose irradiated mice at day 7, early and sustained reduction of CD8+ T cell numbers was observed in fractionated- dose-irradiated mice from day 2 until day 14. In addition, single-dose irradiation resulted in a Th1 cytokine expression profile, whereas fractionated-dose irradiation drove a Th2 shift. Additionally, increased expression of immune-related factors was observed at early time-points with single-dose irradiation, in contrast to the dose-independent induction following fractionated-dose irradiation.Conclusions: Our results demonstrate that low-dose irradiation modulates the immune response in mice, where the sensitivity and kinetics of the induced response vary according to the dosing method.

Profiling of peripheral blood mononuclear cells does not accurately predict the bronchiolitis obliterans syndrome after lung transplantation

After lung transplantation (LTx), circulating mononuclear cell composition and their subsets may be predictive for the bronchiolitis obliterans syndrome (BOS). We investigated the cellular composition in patients developing BOS, or not, by analyzing peripheral blood taken at multiple time points after transplantation. PBMCs of 11 BOS and 39 non-BOS patients were analyzed by FACS for monocytes, dendritic cells, NK-, NKT-, B- and T cells as well as B- and T cell subsets. Analysis of blood samples taken monthly during the first year post-LTx showed that circulating NK, NKT and dendritic cell percentages were not indicative of BOS development, whereas increases in T cells, monocytes and lowered fractions of B cells were related to BOS development. B- and T cell subset analysis at month 5 post-LTx indicated that IgM+IgD− memory B cells and central memory CD8+ T cells were decreased, whereas NKT cells were increased in BOS patients compared to non-BOS patients. Prior to BOS diagnosis, the composition of specific mononuclear cells on a group level differs from patients remaining BOS free. However, given the overlap in percentages of cellular frequencies between the patient groups investigated, this analysis does not allow prediction or risk stratification for development of BOS in individual patients.

Obesity triggers enhanced MDSC accumulation in murine renal tumors via elevated local production of CCL2.

Obesity is one of the leading risk factors for developing renal cell carcinoma, an immunogenic tumor that is treated clinically with immunostimulatory therapies. Currently, however, the mechanisms linking obesity with renal cancer incidence are unclear. Using a model of diet-induced obesity, we found that obese BALB/c mice with orthotopic renal tumors had increased total frequencies of myeloid-derived suppressor cells (MDSC) in renal tumors and spleens by d14 post-tumor challenge, relative to lean counterparts. Renal tumors from obese mice had elevated concentrations of the known myeloid cell chemoattractant CCL2, which was produced locally by increased percentages of dendritic cells, macrophages, B cells, and CD45- cells in tumors. MDSC expression of the CCL2 receptor, CCR2, was unaltered by obesity but greater percentages of CCR2+ MDSCs were present in renal tumors from obese mice. Of note, the intracellular arginase levels and per-cell suppressive capacities of tumor-infiltrating and splenic MDSCs were unchanged in obese mice relative to lean controls. Thus, our findings suggest that obesity promotes renal tumor progression via development of a robust immunosuppressive environment that is characterized by heightened local and systemic MDSC prevalence. Targeted intervention of the CCL2/CCR2 pathway may facilitate immune-mediated renal tumor clearance in the obese.

Agonistic Anti-TIGIT Treatment Inhibits T Cell Responses in LDLr Deficient Mice without Affecting Atherosclerotic Lesion Development

ObjectiveCo-stimulatory and co-inhibitory molecules are mainly expressed on T cells and antigen presenting cells and strongly orchestrate adaptive immune responses. Whereas co-stimulatory molecules enhance immune responses, signaling via co-inhibitory molecules dampens the immune system, thereby showing great therapeutic potential to prevent cardiovascular diseases. Signaling via co-inhibitory T cell immunoglobulin and ITIM domain (TIGIT) directly inhibits T cell activation and proliferation, and therefore represents a novel therapeutic candidate to specifically dampen pro-atherogenic T cell reactivity. In the present study, we used an agonistic anti-TIGIT antibody to determine the effect of excessive TIGIT-signaling on atherosclerosis.Methods and ResultsTIGIT was upregulated on CD4+ T cells isolated from mice fed a Western-type diet in comparison with mice fed a chow diet. Agonistic anti-TIGIT suppressed T cell activation and proliferation both in vitro and in vivo. However, agonistic anti-TIGIT treatment of LDLr−/− mice fed a Western-type diet for 4 or 8 weeks did not affect atherosclerotic lesion development in comparison with PBS and Armenian Hamster IgG treatment. Furthermore, elevated percentages of dendritic cells were observed in the blood and spleen of agonistic anti-TIGIT-treated mice. Additionally, these cells showed an increased activation status but decreased IL-10 production.ConclusionsDespite the inhibition of splenic T cell responses, agonistic anti-TIGIT treatment does not affect initial atherosclerosis development, possibly due to increased activity of dendritic cells.

Ampicillin-Improved Glucose Tolerance in Diet-Induced Obese C57BL/6NTac Mice Is Age Dependent

Ampicillin has been shown to improve glucose tolerance in mice. We hypothesized that this effect is present only if treatment is initiated prior to weaning and that it disappears when treatment is terminated. High-fat fed C57BL/6NTac mice were divided into groups that received Ampicillin at different ages or not at all. We found that both diet and Ampicillin significantly changed the gut microbiota composition in the animals. Furthermore, there was a significant improvement in glucose tolerance in Ampicillin-treated, five-week-old mice compared to nontreated mice in the control group. At study termination, expressions of mRNA coding for tumor necrosis factor, serum amyloid A, and lactase were upregulated, while the expression of tumor necrosis factor (ligand) superfamily member 15 was downregulated in the ileum of Ampicillin-treated mice. Higher dendritic cell percentages were found systemically in high-fat diet mice, and a lower tolerogenic dendritic cell percentage was found both in relation to high-fat diet and late Ampicillin treatment. The results support our hypothesis that a “window” exists early in life in which an alteration of the gut microbiota affects glucose tolerance as well as development of gut immunity and that this window may disappear after weaning.

Immunological response in mice bearing LM3 breast tumor undergoing Pulchellin treatment

BackgroundRibosome-inactivating proteins (RIP) have been studied in the search for toxins that could be used as immunotoxins for cancer treatment. Pulchellin, a type 2 RIP, is suggested to induce immune responses that have a role in controlling cancer.MethodsThe percentage of dendritic cells and CD4+ and CD8+ T cells in the spleen (flow cytometry), cytokines’ release by PECs and splenocytes (ELISA) and nitric oxide production by PECs (Griess assay) were determined from tumor-bearing mice injected intratumorally with 0.1 ml of pulchellin at 0.75 μg/kg of body weight. Statistical analysis was performed by one-way ANOVA with Tukey’s post hoc test.ResultsPulchellin-treated mice showed significant immune system activation, characterized by increased release of IFN-γ and Th2 cytokines (IL-4 and IL-10), while IL-6 and TGF-β levels were decreased. There was also an increase in macrophage’s activation, as denoted by the higher percentage of macrophages expressing adhesion and costimulatory molecules (CD54 and CD80, respectively).ConclusionsOur results suggest that pulchellin is promising as an adjuvant in breast cancer treatment.

PTU-093 Inappropriate inflammatory responses in the ileum of ulcerative colitis patients

IntroductionInflammation in ulcerative colitis (UC) is restricted to the colon. However, up to 50% of UC patients develop inflammation of the small bowel following restorative proctocolectomy (RPC). We hypothesised that...