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Allergy is a complex array of diseases influenced by innate and adaptive immunity, genetic polymorphisms, and environmental triggers. Atopic dermatitis is a chronic inflammatory skin disease characterized by barrier defects and immune dysregulation, sometimes leading to asthma and food allergies because of the atopic march. During atopic skin inflammation, Langerhans cells and dendritic cells (DCs) in the skin capture and deliver allergen information to local lymph nodes. DCs are essential immune sensors coordinating immune reactions by capturing and presenting antigens to T cells. In the context of allergic responses, DCs play a crucial role in instructing two types of helper T cells—type 2 helper T (Th2) cells and follicular helper T (TFH) cells—in allergic responses and IgE antibody responses. In skin sensitization, the differentiation and function of Th2 cells and TFH cells are influenced by skin-derived factors, including epithelial cytokines, chemokines, and signalling pathways to modify the function of migratory DCs and conventional DCs. In this review, we aim to understand the specific mechanisms involving DCs in allergic responses to provide insights into the pathogenesis of allergic diseases and potential therapeutic strategies. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs) express major histocompatibility complex class II (MHC-II) and are best known for proficiently presenting antigens to T cells, thereby eliciting specific adaptive T cell responses. Moreover, conventional DCs (cDCs) are specifically adept at handling intestinal antigens. Relatively recent discoveries and investigations have proven the existence of a new group of innate lymphocytes that reside in tissues like the intestine. They lack specific antigen receptors and can express MHC-II. These group 3 innate lymphoid cells (ILC3s) comprise a subset of heterogeneous innate lymphocytes that mirror the phenotype and functions of T-helper cells and act in the first line of defense. Considering that ILC3s are crucial for maintaining homeostasis of the intestinal mucosa and are found in niches alongside DCs, we herein describe the roles played by cDCs and ILC3s in the gut, highlighting the most recent studies. We discuss how these cells are alike and differ, constantly pointing out the thin, blurry line that separates cDCs and ILC3s. [ABSTRACT FROM AUTHOR]

The development of human mesenchymal stromal/stem cell (MSC)-based therapy has focused on exploring biological nanoparticles secreted from MSCs. There is emerging evidence that the immunomodulatory and regenerative effects of MSCs can be recapitulated by extracellular vesicles released from MSCs (MSC-EVs). Off-the-shelf allogeneic human MSC products are clinically available to treat acute graft-versus-host disease (GVHD), but real-world data have revealed the limitations of these products as well as their feasibility, safety, and efficacy. MSC-EVs may have advantages over parental MSCs as drugs because of their distinguished biodistribution and importantly dose-dependent therapeutic effects. Recent research has shed light on the role of microRNAs in the mode-of-action of MSC-EVs. A group of specific microRNAs alone or in combination with membrane proteins, membrane lipids, and soluble factors present in MSC-EVs play key roles in the regulation of GVHD. In this concise review, we review the regulation of T-cell-mediated adaptive immunity and antigen-presenting cell-mediated innate immunity by MSC-EVs and the direct regenerative effects on damaged cells in association with the immunopathology of GVHD. [ABSTRACT FROM AUTHOR]

After allogeneic hematopoietic stem cell transplantation (HSCT), donor lymphocytes may contribute to the regression of hematological malignancies and select solid tumors, a phenomenon referred to as the graft-versus-tumor effect (GVT). However, this immunologic reaction is frequently limited by either poor specificity resulting in graft-versus-host disease or the frequency of tumor-specific T cells being too low to induce a complete and sustained anti-tumor response. Over the past 2 decades, it has become clear that the driver of GVT following allogeneic HSCT is T-cell-mediated recognition of antigens presented on tumor cells. With that regard, even though the excitement for using HSCT in solid tumors has declined, clinical trials of HSCT in solid tumors provided proof of concept and valuable insights leading to the discovery of tumor antigens and the development of targeted adoptive cell therapies for cancer. In this article, we review the results of clinical trials of allogeneic HSCT in solid tumors. We focus on lessons learned from correlative studies of these trials that hold the potential for the creation of tumor-specific immunotherapies with greater efficacy and safety for the treatment of malignancies. [ABSTRACT FROM AUTHOR]

Aging is accompanied by reduced remodeling of skeletal muscle extracellular matrix (ECM), which is exacerbated during recovery following periods of disuse atrophy. Mechanotherapy has been shown to promote ECM remodeling through immunomodulation in adult muscle recovery, but not during the aged recovery from disuse. In order to determine if mechanotherapy promotes ECM remodeling in aged muscle, we performed single cell RNA sequencing (scRNA-seq) of all mononucleated cells in adult and aged rat gastrocnemius muscle recovering from disuse, with (REM) and without mechanotherapy (RE). We show that fibroadipogenic progenitor cells (FAPs) in aged RE muscle are highly enriched in chemotaxis genes (Csf1), but absent in ECM remodeling genes compared to adult RE muscle (Col1a1). Receptor-ligand (RL) network analysis of all mononucleated cell populations in aged RE muscle identified chemotaxis-enriched gene expression in numerous stromal cell populations (FAPs, endothelial cells, pericytes), despite reduced enrichment of genes related to phagocytic activity in myeloid cell populations (macrophages, monocytes, antigen presenting cells). Following mechanotherapy, aged REM mononuclear cell gene expression resembled adult RE muscle as evidenced by RL network analyses and KEGG pathway activity scoring. To validate our transcriptional findings, ECM turnover was measured in an independent cohort of animals using in vivo isotope tracing of intramuscular collagen and histological scoring of the ECM, which confirmed mechanotherapy-mediated ECM remodeling in aged RE muscle. Our results highlight age-related cellular mechanisms underpinning the impairment to complete recovery from disuse, and also promote mechanotherapy as an intervention to enhance ECM turnover in aged muscle recovering from disuse. [ABSTRACT FROM AUTHOR]

Polysaccharide A (PSA) is the immunodominant capsular carbohydrate from the gram negative commensal microbe Bacteroides fragilis that has shown remarkable potency in ameliorating many rodent models of inflammatory disease by eliciting downstream suppressive CD4+ T cells. PSA is composed of a zwitterionic repeating unit that allows it to be processed by antigen presenting cells (APCs) and presented by MHCII in a glycosylation-dependent manner. While previous work has uncovered much about the interactions between MHCII and PSA, as well as the downstream T cell response, little is known about how PSA affects the phenotype of MHCII+ APCs, including macrophages. Here, we utilized an unbiased systems approach consisting of RNAseq transcriptomics, high-throughput flow cytometry, Luminex analysis and targeted validation experiments to characterize the impact of PSA-mediated stimulation of splenic MHCII+ cells. The data revealed that PSA potently elicited the upregulation of an alternatively activated M2 macrophage transcriptomic and cell surface signature. Cell-type-specific validation experiments further demonstrated that PSA-exposed bone marrow-derived macrophages (BMDMs) induced cell surface and intracellular markers associated with M2 macrophages compared with conventional peptide ovalbumin (ova)-exposed BMDMs. In contrast to macrophages, we also found that CD11c+ dendritic cells (DCs) upregulated the pro-T cell activation costimulatory molecule CD86 following PSA stimulation. Consistent with the divergent BMDM and DC changes, PSA-exposed DCs elicited an antigen-experienced T cell phenotype in co-cultures, whereas macrophages did not. These findings collectively demonstrate that the PSA-induced immune response is characterized by both T cell stimulation via presentation by DCs, and a previously unrecognized anti-inflammatory polarization of macrophages. [ABSTRACT FROM AUTHOR]

Vaccines are created to help the immune system fight pathogens faster and more effectively, but little is known on how season of the year impacts the immune system response to vaccination. This research was conducted to evaluate how ambient temperature (summer vs fall) impacted antibody production and immune cell type changes in Brahman and Brahmaninfluenced cows. Cows (n = 18) were immunized (2 mL I.M.) with a combination Modified Live Vaccine for Bovine Viral Diarrhea Virus (BVDV) and Infectious Bovine Rhinotracheitis Virus (IBR) on d 0 in either July 2022 (Summer; n = 12) or November 2022 (Fall; n = 6). Blood samples (30 mL/cow) were collected on d -3, 0, 2, 4, 6, 8, 10, 14 post vaccination and transferred to 50 mL conical tubes containing EDTA to separate plasma and peripheral blood mononuclear cells (PBMC). Density gradient centrifugation was used to isolate PBMC. Serum samples were also collected (10 mL/cow) on d -3, 0, 14. Cells were incubated with propidium iodide and antibody surface cell markers for CD4, CD8, CD25, CD14, CD86, and CD335. An Amnis FlowSight flow cytometer was used to determine the percentage of each cell type in the PBMC. Concentrations of antibodies for BVDV and IBR were determined in serum samples collected pre-vaccination (d -3 and 0) and on d 14. Differences in antibody titers and leukocyte populations were analyzed as repeated measures using the MIXED model procedure in SAS. There were no differences in IBR (P = 0.2) or BVDV (P = 0.47) antibody concentrations between seasons. Percentage of antigen presenting cells (CD14+) was greater in the Summer compared with the Fall (P = 0.01; Summer=11.7 ± 1%; Fall = 7.3 ± 1.1%), but natural killer cells (CD335+) were greater in the Fall compared with the Summer (P = 0.002; Summer = 0.6 ± 0.6%; Fall = 4.4±0.7%). There was a significant treatment by time interaction for antigen presenting cells (P = 0.04), T-helper cells (CD4+; P = 0.01), activated T-helper cells (CD4+CD25+; P ≤ 0.0001), activated cytotoxic T-cells (CD8+CD25+; P = 0.03), activated T-cells (CD25+; P ≤ 0.0001), and natural killer cells (P ≤ 0.0001), but there was no difference between seasons in activated antigen presenting cells (CD14+CD86+; P = 0.19). From pre-vaccination to d 14, natural killer cells were elevated during the Fall compared with the Summer on all days (P = 0.04). Antigen presenting cells were greater in the Summer compared with the Fall on d 4, 10 and 14 (P < 0.02). T-helper cells, activated T-helper cells, activated cytotoxic T-cells, and activated T-cells increased post-vaccination in the Fall, but did not change during the Summer. Thus, ambient temperature (summer vs fall) did not directly impact production of antibodies for IBR or BVDV but did induce changes in specific immune cells following vaccination. [ABSTRACT FROM AUTHOR]

Objectives: We aimed to clarify the characteristics of heme oxygenase (HO)-1 expressing cells in the synovium from rheumatoid arthritis (RA) and osteoarthritis (OA), and to investigate the co-expression of HO-1 and IgG-Fc/HLA-DR complex. Methods: The characteristics of HO-1 expressing cells in the synovium were investigated by using immunohistochemistry. The co-expression of HO-1 and IgG-Fc/HLA-DR complex was examined by an in situ proximity ligation assay (PLA) with immunofluorescence. HO-1 mRNA was investigated by reverse transcription-polymerase chain reaction. Results: The number of HO-1+; cells from the RA synovium is higher than that from OA synovium. The double positive cells of HO-1 and IgG-Fc/HLA-DR complex were detected by the in situ PLA with immunofluorescence in RA synovium. HO-1 mRNA was detected in both RA and OA synovium. Conclusion: A portion of HO-1+ cells with IgG-Fc/HLA-DR complex in lining layer of RA may be concluded as one of antigen presenting cells in RA and may be involved in production of RF. [ABSTRACT FROM AUTHOR]

Regulation of immune function continues to be one of the most well‐recognized extraskeletal actions of vitamin D. This stemmed initially from the discovery that antigen presenting cells such as macrophages could actively metabolize precursor 25‐hydroxyvitamin D (25D) to active 1,25‐dihydroxyvitamin D (1,25D). Parallel observation that activated cells from the immune system expressed the intracellular vitamin D receptor (VDR) for 1,25D suggested a potential role for vitamin D as a localized endogenous modulator of immune function. Subsequent studies have expanded our understanding of how vitamin D exerts effects on both the innate and adaptive arms of the immune system. At an innate level, intracrine synthesis of 1,25D by macrophages and dendritic cells stimulates expression of antimicrobial proteins such as cathelicidin, as well as lowering intracellular iron concentrations via suppression of hepcidin. By potently enhancing autophagy, 1,25D may also play an important role in combatting intracellular pathogens such as M. tuberculosis and viral infections. Local synthesis of 1,25D by macrophages and dendritic cells also appears to play a pivotal role in mediating T‐cell responses to vitamin D, leading to suppression of inflammatory T helper (Th)1 and Th17 cells, and concomitant induction of immunotolerogenic T‐regulatory responses. The aim of this review is to provide an update on our current understanding of these prominent immune actions of vitamin D, as well as highlighting new, less well‐recognized immune effects of vitamin D. The review also aims to place this mechanistic basis for the link between vitamin D and immunity with studies in vivo that have explored a role for vitamin D supplementation as a strategy for improved immune health. This has gained prominence in recent months with the global coronavirus disease 2019 health crisis and highlights important new objectives for future studies of vitamin D and immune function. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research. [ABSTRACT FROM AUTHOR]

Flucloxacillin is a β-lactam antibiotic associated with a high incidence of drug-induced liver reactions. Although expression of human leukocyte antigen (HLA)-B*57:01 increases susceptibility, little is known of the pathological mechanisms involved in the induction of the clinical phenotype. Irreversible protein modification is suspected to drive the reaction through the modification of peptides that are presented by the risk allele. In this study, the binding of flucloxacillin to immune cells was characterized and the nature of the peptides presented by HLA-B*57:01 was analyzed using mass spectrometric-based immunopeptidomics methods. Flucloxacillin modification of multiple proteins was observed, providing a potential source of neoantigens for HLA presentation. Of the peptides eluted from flucloxacillin-treated C1R-B*57:01 cells, 6 putative peptides were annotated as flucloxacillin-modified HLA-B*57:01 peptide ligands (data are available via ProteomeXchange with identifier PXD020137). To conclude, we have characterized naturally processed drug-haptenated HLA ligands presented on the surface of antigen presenting cells that may drive drug-specific CD8+ T-cell responses. [ABSTRACT FROM AUTHOR]

The male accessory glands (MAGs) in insects are pair(s) of internal reproductive organs that produce and secrete the plasma component of seminal fluid. In various insects, MAG size is important for male reproductive success because the fluid provides physiologically active substances and/or nutrients to females to control sperm as well as female reproductive behaviors. Although the MAG epithelial cells in most insect species are standard mononucleate cells, those in some insect taxa are binucleate due to incomplete cytokinesis (e.g. Drosophila [Fallén] [Diptera: Drosophilidae]) or cell fusion (e.g. Cimex [Linnaeus] [Hemiptera: Cimicidae]). In the case of Drosophila , the apicobasal position of the two nuclei relative to the epithelial plane changes from vertical to horizontal after nutrient intake, which allows the volume of the MAG cavity to expand effectively. On the other hand, in the case of Cimex , the positions of the two nuclei do not change apicobasally in response to feeding, but their position relative to the proximodistal axis varies depending on the tubular/spherical organ morphology. Here, we report that the MAG of the benthic water bug Aphelocheirus vittatus (Matsumura) (Hemiptera: Aphelochiridae) shows binucleation in all epithelial cells. Despite the phylogenetically close relationship between Aphelocheirus and Cimex , the MAG cells in Aphelocheirus showed a Drosophila -like apicobasal change in the position of the two nuclei in response to feeding. Furthermore, the cytological processes during binucleation are more similar to those in Drosophila (incomplete cytokinesis) than to those in Cimex (cell fusion). These results indicate that the physiological role and mechanism of binucleation in MAG cells changed during the evolution of Hemiptera. [ABSTRACT FROM AUTHOR]

Background: Chlamydia trachomatis and Chlamydia muridarum are intracellular bacterial pathogens of mucosal epithelial cells. CD4 T cells and major histocompatibility complex (MHC) class II molecules are essential for protective immunity against them. Antigens presented by dendritic cells (DCs) expand naive pathogen-specific T cells (inductive phase), whereas antigens presented by epithelial cells identify infected epithelial cells as targets during the effector phase. We previously showed that DCs infected by C trachomatis or C muridarum present epitopes from a limited spectrum of chlamydial proteins recognized by Chlamydia-specific CD4 T cells from immune mice.Methods: We hypothesized that Chlamydia-infected DCs and epithelial cells present overlapping sets of Chlamydia-MHC class II epitopes to link inductive and effector phases to generate protective immunity. We tested that hypothesis by infecting an oviductal epithelial cell line with C muridarum, followed by immunoaffinity isolation and sequencing of MHC class I- and II-bound peptides.Results: We identified 26 class I-bound and 4 class II-bound Chlamydia-derived peptides from infected epithelial cells. We were surprised to find that none of the epithelial cell class I- and class II-bound chlamydial peptides overlapped with peptides presented by DCs.Conclusions: We suggest the discordance between the DC and epithelial cell immunoproteomes has implications for delayed clearance of Chlamydia and design of a Chlamydia vaccine. [ABSTRACT FROM AUTHOR]

We previously reported that MDA-MB-231 and MCF-7 cells, which are breast cancer cell lines and have cancer and cancer-initiating cells (CICs), were killed following normothermic microwave irradiation in which the cellular temperature was maintained at 37°C. In this study, we investigated the percentages of live or dead cells among CD44+/CD24− cells, which were defined as CICs among MDA-MB-231 and MCF-7 cells, and other types of cells in response to microwave irradiation. CD44+/CD24− cells among MDA-MB-231 cells were killed, thereby decreasing the number of cells, whereas the number of live CD44+/CD24− MCF-7 cells was increased following microwave irradiation. Moreover, adhesion, invasion, and migration were decreased in MDA-MB-231 cells, and the activation of matrix metalloproteinase-2 (MMP-2) in MDA-MB-231 cells was increased following microwave irradiation. These decreased cell activities might have been caused by MMP-2 activation and population changes in CD44+/CD24− in MDA-MB-231 cells. Abbreviations: APC: allophecocyanin; CBB: coomassie Brilliant Blue; CD: cluster of differentiation; CICs: cancer-initiating cells; FACS: fluorescence-activated cell sorting; FBS: fetal bovine serum; FITC: fluorescein isothiocyanate; FTDT: finite-difference time domain; HER2: human epidermal growth factor receptor type 2; PI: propidium iodide. Functional changes of MDA-MB-231 cells by normothermic microwave irradiation. [ABSTRACT FROM AUTHOR]

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Discussion on TLR3 triggering in CD4 T cells induces IFN beta and IL10-producing iTregs that suppress food allergy. The professional antigen presenting cells, such as dendritic cells (DCs), process and present peptides from food antigens on their MHC class II molecules, and subsequently orchestrate antigen-specific T cell responses. In conclusion, activation of TLR3 by polyI:C administration induces IFN + FOXP3+ Tregs, which prevented FA development and inhibited existing FA in mice. [Extracted from the article]

Summary: The finding that dendritic cells (DCs) orchestrate innate and adaptive immune responses has stimulated research on harnessing DCs for developing more effective vaccines for DC therapy. The expression of cytomegalovirus (CMV) antigens in glioblastoma multiforme (GBM) presents a unique opportunity to target these viral proteins for tumour immunotherapy. Here, we demonstrate that Vγ9γδT cells, innate immune cells activated by zoledronate (Z) and Vα24 natural killer (Vα24NK) cells, innate/adaptive immune cells activated by α‐galactosylceramide (G) can link innate and adaptive immunities through cross‐talk with interferon (IFN) DCs from patients with glioblastoma multiforme (GBM) and healthy donors in a manner that can amplify the activation and proliferation of CMVpp65‐specific CD8+ T cells. The IFN DCs derived from patients with GBM used in this study express lower levels of programmed cell death ligand (PD)‐L1 and PD‐L2 and higher levels of C‐C receptor 7 (CCR7) than the most commonly used mature interleukin (IL)‐4 DCs. The expression level of programmed cell death 1 (PD‐1) on CD8+ T cells, including CMVpp65‐specific CD8+ T cells, expanded by IFN DCs pulsed with the CMVpp65‐peptide and Z plus G (IFN DCs/P+Z+G), was lower than that expanded by IFN DCs pulsed with the peptide alone (IFN DCs/P). Multi‐functional T cells, including human leucocyte antigen (HLA)‐A*0201‐restricted CMVpp65‐specific CD8+ T cells, Vγ9γδT cells and Vα24NKT cells, efficiently kill the HLA‐A*0201‐positive GBM cell line expressing CMVpp65 protein (T98G). These findings indicate that DC therapy using IFN DCs/P+Z+G and/or CTL therapy using CMVpp65‐specific CD8+ T cells expanded by IFN DCs/P+Z+G may lead to a good clinical outcome for patients with GBM. [ABSTRACT FROM AUTHOR]

Abstract: Aims: The aims of this study were to develop an effective M cell‐targeting oral vaccine, involving Lactobacillus casei to deliver the porcine epidemic diarrhoea virus (PEDV) core neutralizing epitope (COE) antigen conjugated with M cell‐targeting peptide Co1 as an adjuvant, against PEDV infection. Methods and Results: Genetically engineered L. casei 393 (L393) strains expressing PEDV COE antigen only (pPG‐COE/L393) or fused‐expressing COE and M cell‐targeting peptide Co1 (pPG‐COE‐Co1/L393) were constructed, and the immunogenicity upon administration as an oral vaccine was evaluated. The results showed that higher anti‐PEDV serum IgG and mucosal SIgA antibody responses were induced in mice orally immunized with strain pPG‐COE‐Co1/L393 as compared to the mice immunized with strain L393 expressing COE alone or carrying the empty plasmid. In addition, the use of the Co1 ligand elicited a splenocyte proliferative response more effectively in comparison with the COE antigen alone and supported a skewed T helper 2 type of immune response against PEDV. Conclusions: pPG‐COE‐Co1/L393 can effectively induce mucosal, humoural and Th2‐type cellular immune responses against PEDV infection via oral administration. Furthermore, M cell‐targeting peptide ligand Co1 is a good mucosal adjuvant. Significance and Impact of the Study: Lactobacillus casei delivering the COE antigen of PEDV conjugated with a M cell‐targeting peptide Co1 as an immune adjuvant is a promising oral vaccine candidate for PEDV. [ABSTRACT FROM AUTHOR]

Objectives α-Galactosylceramide (α-GalCer), a synthetic glycosphingolipid that exhibits potent immunostimulatory effects through activation of natural killer T ( NKT) cells, can be used to treat conditions such as atopy, cancer, infection and autoimmunity. Administration of therapeutics through the oral route has advantages such as patient convenience, safety and reduced cost; however, there has been little research to investigate whether oral delivery of α-GalCer is possible. The aim of this study was therefore to determine whether α-GalCer formulated in either DMSO/Tween 80 or in liposomes, could access lymphoid tissue and stimulate immune activation following oral administration. Methods Fluorescently labelled cationic liposomes incorporating α-GalCer were prepared, characterized and administered by oral gavage to fasted mice. Key findings Liposomes were detected inside the Peyer's patches ( PPs), in the subepithelial dome just under the follicle-associated epithelium. CD11b+ cells and CD11c+ were shown to have taken up the formulation in a higher proportion compared to the total cell proportion in the PPs, suggesting that cells with these markers may be the prominent antigen-presenting cells involved in selective uptake. Finally, the liposomal formulation demonstrated a higher degree of immune stimulation compared to the DMSO/Tween 80 solubilized α-GalCer in the PPs, mesenteric lymph nodes and spleen as shown by the increased expression of IL-4 m RNA expression and increased proportion of NKT cells at 6 h and 3 days after administration. Conclusions These results show that oral delivery of a liposomal α-GalCer can stimulate local and systemic immune responses to a different degree compared to the non-liposomal form. [ABSTRACT FROM AUTHOR]

Review of in vivo targeting of tumor antigens to lectin receptors on antigen‐presenting cells using antibodies or ligands may improve the antitumor efficacy of vaccines. There is a growing understanding of why certain patients do or do not respond to checkpoint inhibition therapy. This opens new opportunities to reconsider and redevelop vaccine strategies to prime an anticancer immune response. Combination of such vaccines with checkpoint inhibitors will both provide the fuel and release the brake for an efficient anticancer response. Here, we discuss vaccine strategies that use C‐type lectin receptor (CLR) targeting of APCs, such as dendritic cells and macrophages. APCs are a necessity for the priming of antigen‐specific cytotoxic and helper T cells. Because CLRs are natural carbohydrate‐recognition receptors highly expressed by multiple subsets of APCs and involved in uptake and processing of Ags for presentation, these receptors seem particularly interesting for targeting purposes. [ABSTRACT FROM AUTHOR]

IL18‐dependent Rae‐1 upregulation on accessory cells is mediated by the MyD88‐PI3K‐GSK3 pathway, providing important insights into the design of effective NK cell‐based immunotherapies. NK cells are critical for the control of viral infections. Studies have shown that efficient NK cell activation in response to infection with VV in vivo requires multiple pathways, including the NKG2D pathway. We have recently shown that IL‐18 is necessary for the activation of NK cells through upregulation of the NKG2D ligand Rae‐1 on DCs upon VV infection. However, how IL‐18R signaling on the accessory cells contributes to Rae‐1 up‐regulation remains to be defined. In this study, we found IL‐18‐mediated Rae‐1 up‐regulation in accessory cells, including macrophages and DCs, to be dependent on the MyD88‐PI3K pathway. We further found that IL‐18 signaling through PI3K led to inhibition of GSK‐3, which we found to be a negative regulator of Rae‐1. Finally, we demonstrated that in vivo inhibition of GSK‐3 could restore Rae‐1 up‐regulation on IL18R−/− DCs and partially rescue NK‐cell activation against VV, leading to improved viral control in IL‐18R−/− mice. Our results showed that IL18‐dependent Rae‐1 up‐regulation on accessory cells is mediated by the MyD88‐PI3K‐GSK3 pathway. These observations may provide important insights into the design of effective NK cell‐based immunotherapies. [ABSTRACT FROM AUTHOR]

Sjögren's syndrome is the second most common rheumatic disease in which autoimmune response targets exocrine glands (salivary and lacrimal glands) result in clinical symptoms of dry mouth and dry eye. Inflammation of the lacrimal gland induces tear abnormalities that contribute to the inflammation of the ocular surface, which includes ocular mucosa. Thrombospondin-1 (TSP-1) plays a critical regulatory role in the ocular mucosa and as such TSP-1-/- mice develop spontaneously chronic ocular surface inflammation associated with Sjögren's syndrome. The autoimmune pathology is also accompanied by a peripheral imbalance in regulatory (Treg) and inflammatory Th17 effectors. In this study, we demonstrate an in-vitro effect of a CD47-binding TSP-derived peptide in the induction of transforming growth factor (TGF)-β1-secreting forkhead box protein 2 (Foxp3+) Tregs from activated CD4+CD25- T cells and the inhibition of pathogenic T helper type 17 (Th17)-promoting interleukin (IL)-23 derived from antigen-presenting cells. The in-vivo administration of this peptide promotes Foxp3+ Treg induction and inhibition of Th17 development. Consistent with these results, topical administration of CD47-binding TSP peptide, both before and after the onset of the disease, attenuates clinical symptoms of SS-associated dry eye in TSP-1-/- mice. Augmented expression of Foxp3 detected in the draining lymph nodes of TSP peptide -treated mice compared to those treated with control peptide suggests the ability of TSP peptide to restore peripheral immune imbalance. Thus, our results suggest that TSP-derived peptide attenuates Sjögren's syndrome-associated dry eye and autoimmune inflammation by preventing Th17 development while promoting the induction of Tregs. Collectively, our data identify TSP-derived peptide as a novel therapeutic option to treat autoimmune diseases. [ABSTRACT FROM AUTHOR]

B cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) help in B cell activation, maintenance and plasma cell survival. B cell infiltration has been demonstrated in kidneys of patients with lupus nephritis (LN). Serum levels of BAFF and APRIL have shown inconsistent relationships with lupus disease activity. We evaluated urinary levels of BAFF and APRIL as biomarker for LN. Thirty-six patients with proliferative lupus nephritis (AN), 10 with active lupus without nephritis (AL) and 15 healthy controls (HC) were studied. APRIL and BAFF levels were measured in both serum and urine using enzyme-linked immunosorbent assay (ELISA). Urine levels were normalized for urinary creatinine excretion. Urine levels were correlated with conventional disease activity markers and histology. Levels were reassessed in 20 AN patients at 6 months after treatment with cyclophosphamide. Urinary APRIL (uAPRIL) and BAFF (uBAFF) levels were raised significantly in AN. uAPRIL, but not uBAFF, correlated moderately with renal Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) in AN ( r = 0·36, P < 0·05). On receiver operator curve (ROC) analysis, uBAFF and uAPRIL showed an area under the curve (AUC) of 0·825 and 0·781, respectively, in differentiating between nephritis and non-nephritis, which performed better than low C3, C4 and raised anti-dsDNA antibodies. There was no correlation of serum levels with uBAFF ( r = 0·187, P = 0·261) and uAPRIL ( r = 0·114, P = 0·494). uAPRIL levels reduced after treatment (mean 125 pg/mg to 36 pg/mg, P < 0·05). uBAFF levels reduced in 16 responders while two of four non-responders had increase in levels. Thus, uBAFF and uAPRIL are potential biomarkers of proliferative lupus nephritis. [ABSTRACT FROM AUTHOR]

Objectives Dendritic cells ( DCs) are antigen-presenting cells, essential for recognition and presentation of pathogens to T cells. Propolis, a resinous material produced by bees from various plants, exhibits numerous biological properties, highlighting its immunomodulatory action. Here, we assayed the effects of propolis on the maturation and function of human DCs. Methods DCs were generated from human monocytes and incubated with propolis and LPS. NF-κB and cytokines production were determined by ELISA. micro RNA's expression was analysed by RT- qPCR and cell markers detection by flow cytometry. Colony-forming units were obtained to assess the bactericidal activity of propolis-treated DCs. Key findings Propolis activated DCs in the presence of LPS, inducing NF- kB, TNF-α, IL-6 and IL-10 production. The inhibition of hsa-miR-148a and hsa-miR-148b abolished the inhibitory effects on HLA- DR and pro-inflammatory cytokines. The increased expression of hsa-miR-155 may be correlated to the increase in TLR-4 and CD86 expression, maintaining LPS-induced expression of HLA- DR and CD40. Such parameters may be involved in the increased bactericidal activity of DCs against Streptococcus mutans. Conclusion Propolis modulated the maturation and function of DCs and may be useful in the initial steps of the immune response, providing a novel approach to the development of DC-based strategies and for the discovery of new immunomodulators. [ABSTRACT FROM AUTHOR]

Background: Visceral leishmaniasis (VL) is a potentially fatal parasitic disease associated with fever, cachexia and impaired protective T-cell responses against the parasite.Methods: Peripheral blood leukocytes from 105 subjects with VL and healthy control subjects from the endemic region of Muzaffarpur, Bihar, India, were compared using flow cytometry and reverse-transcriptase quantitative polymerase chain reaction. Findings were correlated with clinical data.Results: An expanded population of low-density neutrophils that expressed HLA-DR, CD80 and CD86 was observed in subjects with VL. This neutrophil population contracted after successful treatment of disease. Plasma from patients with acute VL was able to induce similar high-level HLA-DR expression in neutrophils from healthy subjects. HLA-DR+ neutrophils from subjects with VL did not stimulate T-cell proliferation, but they did express higher programmed cell death ligand-1 (PDL1) than other neutrophils, and lymphocytes of the same subjects expressed high programmed cell death 1 (PD1).Conclusions: Patients with acute VL have expanded circulating low-density neutrophils expressing markers of antigen presentation, which diminish after treatment. Development of HLA-DR+ neutrophils is stimulated, at least in part, by components of plasma from patients with acute disease. Although we found no evidence that they act as antigen-presenting cells, these neutrophils expressed markers implicating a role in T-cell exhaustion. [ABSTRACT FROM AUTHOR]

The lack of persistence of infused T cells is a principal limitation of adoptive immunotherapy in man. Interleukin (IL)-15 can sustain memory T cell expansion when presented in complex with IL-15Rα (15Rα/15). We developed a novel in-vitro system for generation of stable 15Rα/15 complexes. Immunologically quantifiable amounts of IL-15 were obtained when both IL-15Rα and IL-15 genes were co-transduced in NIH 3T3 fibroblast-based artificial antigen-presenting cells expressing human leucocyte antigen (HLA) A:0201, β2 microglobulin, CD80, CD58 and CD54 [A2-artificial antigen presenting cell (AAPC)] and a murine pro-B cell line (Baf-3) (A2-AAPC15Rα/15and Baf-315Rα/15). Transduction of cells with IL-15 alone resulted in only transient expression of IL-15, with minimal amounts of immunologically detectable IL-15. In comparison, cells transduced with IL-15Rα alone (A2-AAPCRα) demonstrated stable expression of IL-15Rα; however, when loaded with soluble IL-15 (sIL-15), these cells sequestered 15Rα/15 intracellularly and also demonstrated minimal amounts of IL-15. Human T cells stimulated in vitro against a viral antigen (CMVpp65) in the presence of 15Rα/15 generated superior yields of high-avidity CMVpp65 epitope-specific T cells [cytomegalovirus-cytotoxic T lymphocytes (CMV-CTLs)] responding to ≤ 10− 13 M peptide concentrations, and lysing targets cells at lower effector : target ratios (1 : 10 and 1 : 100), where sIL-15, sIL-2 or sIL-7 CMV-CTLs demonstrated minimal or no activity. Both soluble and surface presented 15Rα/15, but not sIL-15, sustained in-vitro expansion of CD62L+ and CCR7+ central memory phenotype CMV-CTLs (TCM). 15Rα/15 complexes represent a potent adjuvant for augmenting the efficacy of adoptive immunotherapy. Such cell-bound or soluble 15Rα/15 complexes could be developed for use in combination immunotherapy approaches. [ABSTRACT FROM AUTHOR]

Background: Tonsils play a key role in eliciting immune responses against respiratory pathogens. Little is known about how tonsils contribute to the local immune response after intranasal vaccination. Here, we uniquely report the mucosal humoral responses in tonsils and saliva after intranasal live attenuated influenza vaccine (LAIV) vaccination in children.Methods: Blood, saliva, and tonsils samples were collected from 39 children before and after LAIV vaccination and from 16 age-matched, nonvaccinated controls. Serum antibody responses were determined by a hemagglutination inhibition (HI) assay. The salivary immunoglobulin A (IgA) level was measured by an enzyme-linked immunosorbent assay. Antibody-secreting cell (ASC) and memory B-cell (MBC) responses were enumerated in tonsils and blood.Results: Significant increases were observed in levels of serum antibodies and salivary IgA to influenza A(H3N2) and influenza B virus strains as early as 14 days after vaccination but not to influenza A(H1N1). Influenza virus-specific salivary IgA levels correlated with serum HI responses, making this a new possible indicator of vaccine immunogenicity in children. LAIV augmented influenza virus-specific B-cell responses in tonsils and blood. Tonsillar MBC responses correlated with systemic MBC and serological responses. Naive children showed significant increases in MBC counts after LAIV vaccination.Conclusions: This is the first study to demonstrate that LAIV elicits humoral B-cell responses in tonsils of young children. Furthermore, salivary IgA analysis represents an easy method for measuring immunogenicity after vaccination. [ABSTRACT FROM AUTHOR]

Natural killer T (NKT) cells play a critical role in the host's innate immune response. CD1d-mediated presentation of glycolipid antigens to NKT cells has been established; however, the mechanisms by which NKT cells recognize infected or cancerous cells remain unclear. 5′-AMP activated protein kinase (AMPK) is a master regulator of lipogenic pathways. We hypothesized that activation of AMPK during infection and malignancy could alter the repertoire of antigens presented by CD1d and serve as a danger signal to NKT cells. In this study, we examined the effect of alterations in metabolism on CD1d-mediated antigen presentation to NKT cells and found that an infection with lymphocytic choriomeningitis virus rapidly increased CD1d-mediated antigen presentation. Hypoxia inducible factors (HIF) enhance T-cell effector functions during infection, therefore antigen presenting cells pretreated with pharmacological agents that inhibit glycolysis, induce HIF and activate AMPK were assessed for their ability to induce NKT-cell responses. Pretreatment with 2-deoxyglucose, cobalt chloride, AICAR and metformin significantly enhanced CD1d-mediated NKT-cell activation. In addition, NKT cells preferentially respond to malignant B cells and B-cell lymphomas express HIF-1α. These data suggest that targeting cellular metabolism may serve as a novel means of inducing innate immune responses. [ABSTRACT FROM AUTHOR]

The recruitment of immune cells to sites of tissue inflammation is orchestrated by chemokine/chemokine receptor networks. Among these, the CXCL13/CXCR5 axis is thought to be involved critically in systemic lupus erythematosus (SLE) and lupus nephritis pathogenesis. Beyond B cell abnormalities, another hallmark of SLE disease is the occurrence of aberrant T cell responses. In particular, double-negative (DN) T cells are expanded in the peripheral blood of patients with SLE and in lupus-prone mice. DN T cells induce immunoglobulin production, secrete proinflammatory cytokines and infiltrate inflamed tissue, including kidneys. We aimed to investigate how CXCR5 deficiency changes immune cell trafficking in murine lupus. We therefore crossed CXCR5-/- mice with B6/lpr mice, a well-established murine lupus model. B cell numbers and B cellular immune responses were diminished in CXCR5-deficient B6/lpr mice. In addition, we observed reduced accumulation of DN T cells in spleen and lymph nodes, paralleled by reduced splenomegaly and lymphadenopathy. In-vivo migration assays revealed reduced migration of CXCR5-deficient DN T cells into lymph nodes, and ex-vivo-activated CXCR5-deficient DN T cells failed to infiltrate kidneys of recipients. Moreover, DN T cells and B cells of CXCR5-deficient B6/lpr mice failed to migrate towards CXCL13 in vitro. We propose that CXCR5 is involved critically in B cell trafficking and germinal cell (GC) formation in murine lupus and in guiding pathogenic DN T cells into lymphoid organs and kidneys, and we therefore describe new pathomechanisms for the CXCL13/CXCR5 axis in SLE. [ABSTRACT FROM AUTHOR]

Background: We sought to understand why some children respond poorly to vaccinations in the first year of life.Methods: A total of 499 children (6-36 months old) provided serum and peripheral blood mononuclear cell samples after their primary and booster vaccination. Vaccine antigen-specific antibody levels were analyzed with enzyme-linked immunosorbent assay, and frequency of memory B cells, functional T-cell responses, and antigen-presenting cell responses were assessed in peripheral blood mononuclear cell samples with flow cytometric analysis.Results: Eleven percent of children were low vaccine responders, defined a priori as those with subprotective immunoglobulin G antibody levels to ≥66% of vaccines tested. Low vaccine responders generated fewer memory B cells, had reduced activation by CD4(+) and CD8(+) T cells on polyclonal stimulation, and displayed lower major histocompatibility complex II expression by antigen-presenting cells.Conclusions: We conclude that subprotective vaccine responses in infants are associated with a distinct immunologic profile. [ABSTRACT FROM AUTHOR]

The breakthrough of induced pluripotent stem cells (iPSCs) has raised the possibility that patient-specific iPSCs can provide autologous cells for cell therapy without the concern for immune rejection. However, the immunogenicity of iPSC-derived cells remains controversial. Using syngeneic C57BL/6 (B6) mouse transplantation model, several studies indicate that B6 iPSC-derived cells exhibit some levels of immunogenicity when transplanted into B6 mice subcutaneously. In contrast, one recent study has concluded that various lineages of B6 iPSC-derived cells exhibit no immunogenicity when transplanted under the kidney capsule of B6 mice. To resolve the controversy concerning this critical issue of iPSC biology, we used the same B6 transplantation model to demonstrate that the immune response toward antigens is dependent on the immune environment of the transplantation site. Immunogenic antigen-expressing B6 embryonic stem cells (ESCs) as well as B6 iPSCs and their terminally differentiated cells survived under the kidney capsule but are immune rejected when transplanted subcutaneously or intramuscularly. The cotransplantation of mature B6 dendritic cells under the kidney capsule leads to immune rejection of B6 iPSC-derived grafts but not B6 ESC-derived grafts, indicating that the lack of detectable immune response to iPSC-derived grafts under the kidney capsule is due to the lack of functional antigen presenting cells. S tem C ells 2016;34:510-515 [ABSTRACT FROM AUTHOR]

CD4+ T helper lymphocytes (Th) orchestrate the immune response after their activation by antigenpresenting cells. Activation of naïve Th cells is reported to generate the reduction in surface epitopes of sialic acid (Sia) in α2,3 and α2,6 linkages. In this work, we report that in spite of this glycophenotype, anti-CD3/anti-CD28-activated purified human naïve Th cells show a significant increase in surface Sia, as assessed by metabolic labeling, compared with resting naïve Th cells, suggesting an increased flux of Sia toward Siaa2,8 glycoconjugates. To understand this increase as a result of ganglioside up-regulation, we observed that very early after activation, human naïve Th cells show an increased expression in surface GD3 and neoexpression of surface GD2 gangliosides, the latter clustering with the T cell receptor (TCR). Also, we report that in contrast to GM2/GD2 synthase null mice, lentiviral vector-mediated silencing of the GM2/GD2 synthase in activated human naïve Th cells reduced efficient TCR clustering and downstream signaling, as assessed by proliferation assays and IL-2 and IL-2R expression, pointing to an important role of this enzyme in activation of human naive Th cells. [ABSTRACT FROM AUTHOR]

It has not gone unnoticed that many of the immunological characteristics of an actively growing tumor are shared by several non-cancer acute and chronic inflammatory diseases.[2] Burns, trauma, and sepsis represent some of the most severe inflammatory challenges to the host. The current study by Patil and colleagues represents an important addition to the expanding data supporting use of checkpoint inhibitors in burns and bacterial sepsis.[7] Sepsis is the most common cause of death in burn patients who survive the first 24-48 h after injury. In patients with burns greater than 15% body surface area, it can be generally expected that all patients will become colonized and infected, and a significant proportion will develop sepsis, some lethal. [Extracted from the article]

Additionally, GABA is upregulated in a wide array of cancers and promotes tumor proliferation, migration, and invasion,10 leading one to speculate that this pro-tumor effect of GABA signaling may be further supported by reducing the cytotoxicity of tumor-infiltrating NK cells. The finding that human and mouse NK cells constitutively express the molecular machinery for synthesis and secretion of GABA, as well as GABA signaling receptors, implies that this pathway influences NK function in noninfectious inflammatory settings. Notably, Bhandage and colleagues find that human and NK cells not only can respond to GABA signaling, but can produce GABA at physiologically relevant levels. [Extracted from the article]

Background: Telomeres provide a key mechanism for protecting the integrity of chromosomes and their attrition after cell division and during aging are evident in lymphocytes. However, the significance of telomere shortening in age-associated decline of immune function is unknown.Methods: We selected 22 HLA-A2-positive healthy older adults who have relatively short or long telomere lengths to compare their antibody response against the influenza vaccine, and their CD8(+) T-cell response against an influenza antigen.Results: B cells from individuals with a robust antibody response to the influenza vaccine had significantly longer telomeres than those with a poor antibody response. Monocyte-derived antigen-presenting cells of both short and long telomere groups induced similar expansions of influenza M1-specific CD8(+) T cells. Vaccination did not increase M1-specific CD8(+) T cells in blood, but M1-specific CD8(+) T cells from the long telomere group exhibited significantly greater expansion in vitro than those from the short telomere group. Finally, M1-specific CD8(+) T cells that underwent more expansions had significantly longer telomeres than cells with fewer divisions.Conclusions: Telomere length is positively associated with a robust lymphocyte response, and telomere attrition may contribute to the age-associated decline of adaptive immunity. [ABSTRACT FROM AUTHOR]

Naive CD4+ T cells depleted of natural Treg (CD25+) cells proliferate extensively when exposed to a fecal extract [enteroantigen (eAg)] pulsed on antigen-presenting cells (APC). When transplanted into SCID recipient mice, the CD25-depleted T cells induce a chronic colitis with a lethal course. We observed here that if T cells, pre-activated for 48 h by eAg from BALB/c or SCID mice, are removed and then reexposed to either of the two sources of antigen, these T cells have completely lost their anti-eAg proliferative capacity in vitro. This observation indicates that eAgs derived from Balb/c and SCID mice are recognized by similar subsets of T cells. However, when transferred into SCID mice, eAg-activation-depleted T cells are still capable of inducing a severe colitis fully comparable with the disease induced by naive CD4+ T cells [ABSTRACT FROM AUTHOR]

Objectives: Crystal-storing histiocytosis (CSH) is an uncommon finding in plasma cell neoplasms. CSH is thought to be an intralysosomal deposition of secreted paraproteins or immunoglobulins, which usually express κ immunoglobulin light chains that finally aggregate in crystals. Because of its rarity, CSH in bone marrow often makes diagnosis difficult. Methods: A 57-year-old woman had IgA κ monoclonal proteinemia and monoclonal proteinuria. In the bone marrow aspirate, plasma cells were initially counted less than what would be expected, whereas histiocytes with intracellular crystals were increased. Then, we used α-naphthyl acetate esterase (ANAE) staining to distinguish between true histiocytes and plasma cells. Immunostaining for κ, CD138, CD56, and CD68 was performed on a bone marrow biopsy specimen. Results: True histiocytes containing crystalline inclusions were stained strongly for ANAE, while unstained cells with intracytoplasmic crystals represented plasma cells. The biopsy specimen revealed diffuse infiltration of CD138-positive plasma cells. We also confirmed the presence of plasma cells, histiocytes, and their crystallized inclusions with the immunostaining. The patient was finally diagnosed with plasma cell myeloma. Conclusions: The diagnosis was challenging; the bone marrow findings resembled features of other histiocytic disorders. The use of immunohistochemistry enabled the diagnosis of CSH in the presence of plasma cell myeloma. [ABSTRACT FROM AUTHOR]

Objectives: To demonstrate and confirm the existence of cyclin D1-positive diffuse large B-cell lymphoma (DLBCL) with IGH-CCND1 rearrangement and discuss the rationale of differentiating this entity from blastoid and pleomorphic variants of mantle cell lymphoma (MCL). Methods: Two cyclin D1-positive lymphomas with morphologic features of DLBCL and IGH-CCND1 translocations were characterized with respect to clinical features, as well as morphologic, immunophenotypic, cytogenetic, and molecular findings. Results: The large tumor cells were CD20+, CD5-, CD10-, BCL6+, MUM1+, and cyclin D1+ in both cases. SOX11 was negative. Epstein-Barr virus-encoded RNA in situ hybridization demonstrated diffuse positivity in case 1. BCL6 and IGH-CCND1 rearrangements were identified by fluorescence in situ hybridization in both cases. Specifically, the diagnosis of a relapsed DLBCL with acquisition of IGH-CCND1 was rendered for case 1, molecularly confirmed by the detection of identical monoclonal IGH rearrangements between the initial diagnostic DLBCL and relapse lymphoma. Conclusions: Our study demonstrates convincingly that IGH-CCND1 rearrangement leading to cyclin D1 overexpression can occur in DLBCL and pose a potential diagnostic pitfall, requiring thorough knowledge of the clinicopathologic findings to allow accurate discrimination from a blastoid or pleomorphic MCL. The coexistence of IGH-CCND1 and IGH-BCL6 rearrangements suggest that BCL6 and cyclin D1 may cooperate in the pathogenesis of DLBCL. [ABSTRACT FROM AUTHOR]

Objectives: While useful in diagnosing angiosarcomas, CD31 can also highlight histiocytes within soft tissue tumors and lead to errors in diagnosis. We sought to determine how often CD31 highlights cutaneous histiocytomas and histiocytoma mimics. Methods: We examined eight epithelioid cell histiocytomas (ECHs), 12 xanthogranulomas (XGs), nine cases of Langerhans cell histiocytosis (LCH), eight reticulohistiocytomas, 11 xanthomas, 29 atypical fibroxanthomas, nine granular cell tumors, four cases of angiolymphoid hyperplasia with eosinophilia, nine intradermal Spitz nevi, and nine angiosarcomas with antibodies directed against CD31, CD34, CD163, and factor VIII. Results: CD31 marked cells in three of 12 XGs, four of nine cases of LCH, one of eight reticulohistiocytomas, one of 11 xanthomas, 10 of 29 atypical fibroxanthomas, four of four cases of angiolymphoid hyperplasia with eosinophilia, nine of nine angiosarcomas, zero of nine granular cell tumors, and zero of eight ECHs. CD34 and factor VIII were negative in all nonvascular cases. Conclusions: Our results indicate that CD31 can mark lesional cells and imitate vascular tumors in cutaneous histiocytomas and histiocytoma mimics, an error that can be avoided by using a panel of antibodies. [ABSTRACT FROM AUTHOR]

Objectives: The flow cytometric evaluation of peripheral lymphocytosis has led to a dramatic increase in the diagnosis of early stage chronic lymphocytic leukemia (CLL) and monoclonal B-cell lymphocytosis (MBL). Few studies exist to better delineate the natural history and differences between MBL and CLL. Methods: Applying the recently updated B-lymphocyte threshold of 5 x 109 B lymphocytes/L for the diagnosis of CLL, we evaluated the differences in initial presentation, disease progression, time to treatment (TTT), and 10-year overall survival rates between patients with less than 5 x 10 x 109/L, 5 to 10 x 109/L, and more than 10 x 109/L B cells. These clinical/treatment parameters were also compared among the MBL, 5 to 10 CLL Rai stage 0, and more than 10 CLL Rai stage 0 groups. Results: In total, 310 patients were included, with 67 in the less than 5, 75 in the 5 to 10, and 168 in the more than 10 B-cell groups. Statistically significant differences were seen when comparing the 5 to 10 and more than 10 B-cell groups regarding anemia (P = .021 for median hemoglobin; P = .028 for anemia <11 g/dL), platelet count (P = .041 for median platelet count), splenomegaly (P = .013), initial management plan (P = .012 for observation; P = .0021 for treatment with chemotherapy), and TTT (P = .0033). No statistically significant difference was seen among the MBL, 5 to 10, and more than 10 CLL Rai stage 0 groups regarding TTT and 10-year overall survival. Conclusions: Findings suggest that patients with B-cell counts of 5 to 10 x 109/L behave clinically more similar to patients with B-cell counts of less than 5 x 109/L. [ABSTRACT FROM AUTHOR]

Objectives: To analyze CD200 expression by flow cytometry in a large series of B-cell neoplasms in a variety of tissue types in comparison with benign B-lineage cells. Methods: We measured CD200 expression levels in 505 peripheral blood (PB), bone marrow (BM), and lymphoid tissue biopsy specimens, including 364 cases positive for B-cell leukemias and lymphomas. Results: CD200 expression in chronic lymphocytic leukemia cases was as bright as or brighter than normal PB B cells in nearly all cases, while mantle cell lymphoma (MCL) cases were usually dim or negative. However, rare MCL cases (about 5%) were moderately bright for CD200. Marginal zone lymphomas varied by subtype, with nodal cases brighter, splenic cases dimmer, and extranodal cases heterogeneous for CD200 expression. Follicular lymphoma (FL) cells were brighter for CD200 in BM specimens than in lymph nodes. In some BM specimens, dim CD200 could distinguish FL cells from background hematogones. Large B-cell lymphomas of the non--germinal center type tended to be brighter for CD200 than those of the germinal center type, while Burkitt lymphomas were negative. Conclusions: CD200 staining by flow cytometry can be useful in the differential diagnosis of B-cell neoplasms and in their detection in the BM. [ABSTRACT FROM AUTHOR]

Background Tumor microenvironment, and particularly tumor-associated macrophages (TAMs), represent a key contributing factor in pancreatic ductal adenocarcinoma (PDAC) pathogenesis. Here we report that heparanase (predominant enzyme degrading heparan sulfate, the main polysaccharide found at the cell surface and extracellular matrix) directs tumor-promoting behavior of TAM in PDAC. Methods A mouse model of heparanase-overexpressing pancreatic carcinoma (n = 5 mice/group), tumor-associated macrophages ex vivo, primary wild-type and heparanase-null macrophages, and histological specimens from PDAC patients (n = 16), were analyzed, applying immunostaining, enzyme-linked immunosorbent assay, real-time reverse transcription-polymerase chain reaction, cell proliferation, and heparanase activity assays. All statistical tests are two-sided. Results We found that overexpression of heparanase is associated with increased TAM infiltration in both experimental (P = .002) and human (P = .01) PDAC. Moreover, macrophages derived from heparanase-rich tumors (which grew faster in mouse hosts), display pronounced procancerous phenotype, evidenced by overexpression of MSR-2, IL-10, CCL2, VEGF, and increased production of IL-6, an important player in PDAC pathogenesis. Furthermore, in vitro heparanase enzyme-rendered macrophages (stimulated by necrotic cells which are often present in PDAC tissue) procancerous, as exemplified by their enhanced production of key cytokines implicated in PDAC (including IL-6), as well as by their ability to induce STAT3 signaling and to augment pancreatic carcinoma cell proliferation. In agreement, we observed activation of STAT3 in experimental and clinical specimens of heparanase-overexpressing PDAC. Conclusions Our findings underscore a novel function of heparanase in molecular decision-making that guides cancer-promoting action of TAM and imply that heparanase expression status may become highly relevant in defining a target patient subgroup that is likely to benefit the most from treatment modalities targeting TAM/IL-6/STAT3. [ABSTRACT FROM AUTHOR]

Leptin deficiency enhances the ability of splenic DCs to activate T cellsLeptin is a pleiotropic adipokine that is critical for regulating food intake and energy expenditure and also participates in functions of the immune system, including those of antigen-presenting cells. Here, we assess the effect of leptin deficiency on the function splenic dendritic cells (sDC). sDC from leptin-deficient mice (Lepob) were evaluated ex vivo for phenotype, ability to respond to inflammatory stimuli, to acquire and process antigens and to activate T cells. The data show that Lepob sDC express activation markers similar to controls and respond similarly to LPS activation or anti-CD40 cross-linking. In addition, antigen acquisition and processing by Lepob sDC was similar to controls. However, Lepob sDC elicited higher production of IFN-γ in mixed lymphocyte reactions and increased production of IL-2 by antigen-specific T-cell hybridoma relative to controls. To assess Lepob sDC activation of T cells in vivo, Lepob and control mice were infected systemically with Mycobacterium avium. Lepob mice were significantly better at neutralizing the infection as measured by splenic bacterial load over time. This was mirrored with an increased percentage of activated T cells in M. avium-infected Lepob mice. Thus, although no changes were detected in sDC phenotype, activation, antigen processing or presentation, these DC surprisingly presented an enhanced ability to activate T cells ex vivo and in vivo. These data demonstrate that leptin can modulate DC function and suggest that leptin may dampen T-cell responsiveness in the physiological setting. [ABSTRACT FROM AUTHOR]

Ingestion of Bacillus anthracis spores causes gastrointestinal (GI) anthrax. Humoral immune responses, particularly immunoglobulin A (IgA)–secreting B-1 cells, play a critical role in the clearance of GI pathogens. Here, we investigated whether B. anthracis impacts the function of colonic B-1 cells to establish active infection. GI anthrax led to significant inhibition of immunoglobulins (eg, IgA) and increased expression of program death 1 on B-1 cells. Furthermore, infection also diminished type 2 innate lymphoid cells (ILC2) and their ability to enhance differentiation and immunoglobulin production by secreting interleukin 5 (IL-5). Such B-1–cell and ILC2 dysfunction is potentially due to cleavage of p38 and Erk1/2 mitogen-activated protein kinases in these cells. Conversely, mice that survived infection generated neutralizing antibodies via the formation of robust germinal center B cells in Peyer's patches and had restored B-1–cell and ILC2 function. These data may provide additional insight for designing efficacious vaccines and therapeutics against this deadly pathogen. [ABSTRACT FROM AUTHOR]

Podocytes maintain the structure and function of the glomerular filtration barrier. However, podocytes have recently been implicated in the innate immune response, and their function as non-haematopoietic antigen-presenting cells was highlighted. We have shown previously that excessive expression of the chemokine CXCL13 is a distinctive early event for nephritis in a murine model of systemic lupus erythematosus ( SLE). Furthermore, we found that CXCL13 is elevated significantly in the serum of patients with SLE-nephritis. In this study, we were able to show for the first time that (i) CXCL13 is expressed locally in glomeruli in a model for SLE-nephritis in mice and that (ii) incubation of human podocytes with CXCL13 induces receptor stimulation of CXCR5 with activation of signalling pathways, resulting in (iii) secretion of proinflammatory cytokines and chemokines in culture supernatant. This cytokine/chemokine cocktail can lead to (iv) a neutrophil respiratory burst in isolated human granulocytes. Taken together, our results provide further evidence that CXCL13 is involved in the pathogenesis of glomerulonephritis and that podocytes can play an active role in local proinflammatory immune responses. Thus, CXCL13 could be a direct target for the therapy of glomerulonephritis in general and for SLE-nephritis in particular. [ABSTRACT FROM AUTHOR]

PEI induces robust adjuvant effects when delivered systemicallyPolyethyleneimine (PEI) is an organic polycation used extensively as a gene and DNA vaccine delivery reagent. Although the DNA targeting activity of PEI is well documented, its immune activating activity is not. We recently reported that PEI has robust mucosal adjuvanticity when administered intranasally with glycoprotein antigens. Here, we show that PEI has strong immune activating activity after systemic delivery. PEI administered subcutaneously with viral glycoprotein (HIV-1 gp140) enhanced antigen-specific serum IgG production in the context of mixed Th1/Th2-type immunity. PEI elicited higher titers of both antigen binding and neutralizing antibodies than alum in mice and rabbits and induced an increased proportion of antibodies reactive with native antigen. In an intraperitoneal model, PEI recruited neutrophils followed by monocytes to the site of administration and enhanced antigen uptake by antigen-presenting cells. The Th bias was modulated by PEI activation of the Nlrp3 inflammasome; however its global adjuvanticity was unchanged in Nlrp3-deficient mice. When coformulated with CpG oligodeoxynucleotides, PEI adjuvant potency was synergistically increased and biased toward a Th1-type immune profile. Taken together, these data support the use of PEI as a versatile systemic adjuvant platform with particular utility for induction of secondary structure-reactive antibodies against glycoprotein antigens. [ABSTRACT FROM AUTHOR]