Follicular regulatory T (TFR) cells are a specialized suppressive subset that controls the germinal center (GC) response and maintains humoral self-tolerance. The mechanisms that maintain TFR lineage ...identity and suppressive activity remain largely unknown. Here, we show that expression of Blimp1 by FoxP3+ TFR cells is essential for TFR lineage stability, entry into the GC, and expression of regulatory activity. Deletion of Blimp1 in TFR cells reduced FoxP3 and CTLA-4 expression and increased pro-inflammatory cytokines and spontaneous production of autoantibodies, including elevated IgE. Maintenance of TFR stability reflected Blimp1-dependent repression of the IL-23R-STAT3 axis and activation of the CD25-STAT5 pathway, while silenced IL-23R-STAT3 or increased STAT5 activation rescued the Blimp1-deficient TFR phenotype. Blimp1-dependent control of CXCR5/CCR7 expression also regulated TFR homing into the GC. These findings uncover a Blimp1-dependent TFR checkpoint that enforces suppressive activity and acts as a gatekeeper of GC entry.
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•FoxP3-specific ablation of Blimp1 results in expansion of dysfunctional TFR cells•Inducible deletion of Blimp1 in TFR cells impairs TFR stability and function•Blimp1 controls CTLA4 expression, IL-23R-CD25 and CXCR5-CCR7 axes in TFR cells•Blimp1 controls appropriate homing and positioning of TFR cells into the GC
Shen et al. identify Blimp1 as a critical transcription factor for the proper positioning and stable expression of the suppressive activity of TFR cells that control GC responses. In the absence of Blimp1, unstable TFR cells prematurely migrate into the GC and differentiate into TFH-like cells to promote dysregulated GC responses.
Abstract
There is an unmet need for new influenza vaccine strategies that compensate for impaired vaccine responses in elderly individuals. Here, we evaluated the effectiveness of a single-stranded ...RNA (ssRNA) as an adjuvant to enhance the efficacy of inactivated influenza vaccine (IIV) in mouse models. Immunization with the ssRNA along with IIV reduced viral titers as well as pathological and inflammatory scores in the lungs after influenza challenge in aged mice. ssRNA induced balanced Th1/Th2 responses with an increase in IgA titers. Moreover, the ssRNA adjuvant markedly increased the frequency of influenza HA-specific T cells and IFN-γ production along with the expression of genes related to innate and adaptive immune systems that could overcome immunosenescence in aged mice. Our findings indicate that ssRNA is an efficient vaccine adjuvant that boosts cellular and humoral immunity in aged mice, demonstrating its potential as a novel adjuvant for currently available influenza virus vaccines for elderly individuals.
Research over the past decade has revealed the increasingly complex biologic features of the CD4(+) T-cell lineage. This T-cell subset, which was originally defined on the basis of helper activity in ...antibody responses, expresses receptors that recognize peptides that have been processed and presented by specialized antigen-presenting cells. At the core of the adaptive immune response, CD4 T cells display a large degree of plasticity and the ability to differentiate into multiple sublineages in response to developmental and environmental cues. These differentiated sublineages can orchestrate a broad range of effector activities during the initiation, expansion, and memory phase of an immune response. The contribution of CD4 cells to host defense against pathogenic invasion and regulation of autoimmunity is now well established. Emerging evidence suggests that CD4 cells also actively participate in shaping antitumor immunity. Here, we outline the biologic properties of CD4 T-cell subsets with an emphasis on their contribution to the antitumor response.
We examined our hypothesis that heme-oxygenase-1 (HO-1)-derived carbon monoxide (CO) inhibits the release of high-mobility
group box 1 (HMGB1) in RAW264.7 cells activated with lipopolysaccharide ...(LPS) in vitro and in LPS- or cecal ligation and puncture
(CLP)-induced septic mice in vivo, so that HO-1 induction or CO improves survival of sepsis in rodents. We found that pretreatment
with HO-1 inducers (hemin, cobalt protoporphyrin IX) or transfection of HO-1 significantly inhibited HMGB1 release, which
was blocked by HO-1 small interfering RNA, in cells activated by LPS. Carbon monoxide-releasing molecule 2 (CORM-2) but not
bilirubin or deferoxamine inhibited HMGB1 release in LPS-activated macrophages. Oxyhemoglobin reversed the effect of HO-1
inducers on HMGB1 release. Translocation of HMGB1 from nucleus to cytosol was significantly inhibited by HO-1 inducers, CORM-2,
or HO-1 transfection. Neutralizing antibodies to tumor necrosis factor (TNF)-α, interleukin (IL)-1β, interferon-β, and N Ï -nitro- l -arginine methyl ester hydrochloride but not N -2-(cyclohexyloxyl)-4-nitrophenyl-methane sulfonamide (NS-398) significantly inhibited HMGB1 release in LPS-activated cells.
Production of TNF-α, IL-1β, and IFN-β was significantly reduced by pretreatment of HO-1 inducers, CORM-2, or HO-1 transfection
in LPS-activated cells. Plasma levels of HMGB1 in mice challenged with LPS or CLP were significantly reduced by the administration
of HO-1 inducers or CORM-2, which was accompanied by either reduction (pretreatment) or no change (delayed administration)
of serum TNF-α and IL-1β levels. Regardless of pretreatment or delayed administration, CORM-2 and hemin rescued mice from
lethal endotoxemia and sepsis induced by LPS or CLP. Taken together, we concluded that HO-1-derived CO reduces HMGB1 release
in LPS-activated cells and LPS- or CLP-induced animal model of sepsis.
The conversion of naive T cells into Treg can be achieved in vivo by delivery of antigen under subimmunogenic conditions. Here we have examined several drugs for their ability to enhance the ...conversion process in vivo and have found that the rapamycin analog everolimus potently enhances Treg conversion by interfering with T-cell costimulation, reducing cell divison and thereby activation of DNA methyltransferase 1 as well as by reducing T-cell activation through the ATP-gated P2×7 receptor controlling Ca2⁺ influx. The resulting Tregs exhibit increased stability of Foxp3 expression even when generated in TGFβ-containing media in vitro. Thus the mammalian target of rapamycin (m TOR) inhibitor everolimus in addition to inhibiting immune responses enhances Treg conversion by several distinct pathways. The converted Tregs can be further expanded by injection of IL-2/IL-2ab complexes. These complexes also increase the number of CD25⁺Foxp3⁻ cells that, however, do not represent cytokine secreting effector cells but anergic cells, some of which can secrete IL-10 and can themselves be considered regulatory T cells as well. The combined use of everolimus and IL-2/IL-2ab complexes in vivo makes it feasible to achieve highly effective antigen-driven conversion of naive T cells into Treg and their expansion in vivo and thereby the described protocols constitute important tools to achieve immunological tolerance by Treg vaccination.
Aims/Introduction
Natural killer (NK) cells are cytotoxic lymphocytes critical to human immunity. Previous studies showed correlations between NK cell function and blood glucose concentrations. The ...purpose of the present study was to assess the NK cell activity and various metabolic parameters in people with type 2 diabetes, prediabetes and normal glucose tolerance.
Materials and Methods
A total of 49 participants were enrolled in the study. Anthropometric and biochemical parameters including age, sex, body mass index, smoking status, blood pressure, fasting plasma glucose, C‐peptide, insulin, glycated hemoglobin, total cholesterol, triglyceride, high‐density lipoprotein cholesterol and low‐density lipoprotein cholesterol were assessed. The 75 g oral glucose tolerance test was carried out for 2‐h postload glucose level. Homeostatic model assessment was calculated for insulin resistance and β‐cell function. NK cell activity was measured by detecting the circulating interferon‐gamma level secreted from NK cells.
Results
NK cell activity was lower in patients with type 2 diabetes (768.01 ± 650.35) compared with those with prediabetes (2,396.08 ± 653.76, P < 0.001) and normal glucose tolerance (2,435.31 ± 633.22, P < 0.001). In patients with type 2 diabetes, there was a significant inverse linear relationship between NK cell activity and fasting plasma glucose, glycated hemoglobin, and 2‐h postload glucose level (all P < 0.001). Multiple regression analysis showed glycated hemoglobin to be an independent predictor of NK cell activity in patients with type 2 diabetes.
Conclusions
Compared with individuals with normal glucose tolerance or prediabetes, type 2 diabetes patients have a reduced NK cell activity, and it is significantly related to glucose control.
•Kestose improved clinical symptoms compared to FOS in the mouse model of AD.•Kestose significantly increases CD+Foxp3+Treg cells in MLNs in the AD model.•Kestose increases significantly acetate in ...the feces in the model.
Atopic dermatitis (AD) is recently increasing among populations, but the underlying mechanisms remain controversial. Interactions between the gut microbiota and mucosal immunity are considered to be a crucial etiology. Fructooligosaccharide (FOS), prebiotics have been reported as activators of the gut microbiota.
The aim of this study was to investigate the effects of kestose, the smallest FOS and FOS on atopic dermatitis in mice.
An AD mouse model was developed by (ovalbumin) epidermal sensitization using BALB/c mice. Kestose (1%, 5%, and 10%) or FOS (5%, positive control) was orally administered throughout the study.
In comparison with the values observed for the control AD mice, transepidermal water loss (TEWL), clinical score, and skin inflammation on histopathology were significantly decreased by the oral administration of kestose. Total IgE, thymic stromal lymphopoietin (TSLP) in skin, and IL-4 were also suppressed by this administration. In addition, the population of CD4+Foxp3+ cells in mesenteric lymph nodes (MLNs) and acetate concentrations in feces were significantly increased by kestose treatment.
These findings suggest that kestose activates the gut immune system to induce the tolerance against allergic skin inflammations in AD.
Artificial amplification of gluconeogenic phosphoenolpyruvate carboxykinase (PCK) under glycolytic conditions enables
Escherichia coli
to maintain a greater intracellular ATP concentration during its ...growth phase. To demonstrate the biotechnological benefit of
E. coli
harboring a high intracellular ATP concentration, we compared the recombinant protein synthesis of a soluble protein (enhanced green fluorescence protein, GFP) with that of a secretory protein (alkaline protease, AP), under control of the T7 promoter in
E. coli
BL21(DE3) overexpressing PCK. According to the batch fermentations, the strain overexpressing PCK produced more GFP and AP with a lower increase in biomass than the control strain. In a chemostat culture (
D
= 0.7 h
−1
), the GFP production in the PCK overexpressing strain was 99.0 ± 4.31 mg/g cell, with a biomass of 0.22 g/L, while that of the control strain was 53.5 ± 3.07 mg/g cell, with a biomass of 0.35 g/L. These results indicate that the PCK overexpressing
E. coli
strain harboring high intracellular levels of ATP can be useful as a protein-synthesizing host. The potential uses of the strain and associated rationale are discussed.
Osteopontin (Opn) contributes to diverse biological processes that include immune responses, vascularization, and bone formation. Until recently, studies describing the activities of Opn have focused ...on the cytokine-like properties of the secreted protein. Here, we show that alternative translation of a single Opn mRNA species generates a secreted and intracellular isoform. Utilization of a 5' canonical translation start site generates a protein that includes an N-terminal signal sequence allowing targeting to secretory vesicles and cytokine secretion, whereas usage of a downstream start site generates a shortened protein that lacks the N-terminal signal sequence and localizes mainly to cytoplasm. The coordinated action of these Opn gene products regulates the functional phenotype of subsets of dendritic cells.
•RNA adjuvant was developed from the CrPV intergenic region IRES.•The RNA adjuvant functioned as an adjuvant with protein-based vaccines.•The RNA adjuvant increased vaccine efficacy and induced ...balanced Th1/Th2 response.•The RNA adjuvant enhanced APC chemotaxis.
An ideal adjuvant should increase vaccine efficacy through balanced Th1/Th2 responses and be safe to use. Recombinant protein-based vaccines are usually formulated with aluminum (alum)-based adjuvants to ensure an adequate immune response. However, use of alum triggers a Th2-biased immune induction, and hence is not optimal. Although the adjuvanticity of RNA has been reported, a systematic and overall investigation on its efficacy is lacking. We found that single strand RNA (termed RNA adjuvant) derived from cricket paralysis virus intergenic region internal ribosome entry site induced the expression of various adjuvant-function-related genes, such as type 1 and 2 interferon (IFN) and toll-like receptor (TLR), T cell activation, and leukocyte chemotaxis in human peripheral blood mononuclear cells; furthermore, its innate and IFN transcriptome profile patterns were similar to those of a live-attenuated yellow fever vaccine. This suggests that protein-based vaccines formulated using RNA adjuvant function as live-attenuated vaccines. Application of the RNA adjuvant in mouse enhanced the efficacy of Middle East respiratory syndrome spike protein, a protein-subunit vaccine and human papillomavirus L1 protein, a virus-like particle vaccine, by activating innate immune response through TLR7 and enhancing pAPC chemotaxis, leading to a balanced Th1/Th2 responses. Moreover, the combination of alum and the RNA adjuvant synergistically induced humoral and cellular immune responses and endowed long-term immunity. Therefore, RNA adjuvants have broad applicability and can be used with all conventional vaccines to improve vaccine efficacy qualitatively and quantitively.
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