Systemic immune activation (inflammation) and immunosenescence develop in some people with advancing age. This process, known as “inflamm-aging,” is associated with physical frailty and sarcopenia. Meanwhile, successful antiretroviral therapy has led to a growing number of older HIV-1-infected individuals who face both age-related and HIV-1-related inflammation, which may synergistically promote physical decline, including frailty and sarcopenia. The purpose of our study was to determine if inflammation during treated HIV-1 infection worsens physical impairment in older individuals.
We determined the severity of HIV-associated inflammation and physical performance (strength and endurance) in 21 older HIV-infected individuals (54–69 years) receiving suppressive antiretroviral therapy, balanced for confounding variables including age, anthropometrics, and co-morbidities with 10 uninfected control individuals. Biomarkers for microbial translocation (lipopolysaccharide [LPS]), inflammation (soluble CD14 [sCD14], osteopontin, C-reactive protein [CRP], interleukin-6 [IL-6], soluble ICAM-1 [sICAM-1] and soluble VCAM-1 [sVCAM-1]), and coagulopathy (D-dimer) were assayed in plasma. Activation phenotypes of CD4+T cells, CD8+ T cells and monocytes were measured by flow cytometry. Physical performance was measured by 400 m walking speed, a short physical performance battery [SPPB], and lower extremity muscle strength and fatigue.
Overall physical function was similar in the uninfected and HIV-infected groups. Compared to uninfected individuals, the HIV-infected group had elevated levels of sCD14 (P < 0.001), CRP (P < 0.001) and IL-6 (P = 0.003) and an increased frequency of CD4+ and CD8+ T cells with an immunosenescent CD57+ phenotype (P = 0.004 and P = 0.043, respectively). Neither plasma inflammatory biomarkers nor CD57+ T cells correlated with CD4+ T cell counts. Furthermore, none of the elevated inflammatory biomarkers in the HIV-infected subjects were associated with any of the physical performance results.
When age-related co-morbidities were carefully balanced between the uninfected and HIV-infected groups, no evidence of inflammation-associated physical impairment was detected. Despite careful balancing for age, BMI, medications and co-morbidities, the HIV-infected group still displayed evidence of significant chronic inflammation, including elevated sCD14, CRP, IL-6 and CD57+ T cells, although the magnitude of this inflammation was unrelated to physical impairment.
TLR8 assists in antiviral approach by producing Type 1 INF via MyD88 dependent IRF7 pathway. However, over expression of INFα/β molecule poses threat by developing tolerance in chronic infection cases and enhancing inflammatory response. Here we report a bi-specific siRNA based complex which differentially activates and silences the TLR8 and MYD88 respectively in a negatively regulated fashion.
Outer membrane vesicle from Escherichia coli used for siRNA delivery was observed more efficient when attached with invasive protein Ail along with OmpA (P < 0.001) in HEK293-TLR8 cell line. siRNA complexed with p19 protein was efficient in activating TLR8, confirmed by the increment of INFβ molecules (P < 0.001) in HEK293-TLR8 compared to its counterpart. Fusion of lipid bilayer of endosomal compartment was significant at pH 4.5 when fusogenic peptides (diINF-7) were incubated in membrane vesicle, thus facilitating the escape of siRNA complex to the host cytoplasm in order to silence MyD88 transcript (P < 0.001).
We investigated the activation of TLR8 by bi-specific si-RNA for the production of INFβ. In the same setting we showed that bi-specific si-RNA was able to silence MyD88 transcript in a delayed manner. For the cases of auto immune disease and inflammation where over activation of endosomal TLRs poses serious threat, bi specific siRNA could be used as negative feedback controlled system.
Electronic supplementary material
The online version of this article (doi:10.1186/s12865-015-0109-9) contains supplementary material, which is available to authorized users.
Bi-siRNA; TLR8; INF type I; Outer membrane vesicle; p19; Inflammation; Negative feedback
Pepsin-trypsin resistant gliadin (PT-gliadin) promotes intestinal tissue inflammation and increases paracellular permeability of immunogenic gliadin peptides into the lamina propria. This leads to the complications seen in the pathogenesis of celiac disease (CD). In this study, specific anti-gliadin IgY antibody was produced and evaluated for its efficacy on gliadin induced intestinal integrity impairment and proinflammatory effects on intestinal epithelial (Caco-2) cell culture model for CD.
Caco-2 (passages 20-24) monolayers were subjected to 7 experimental conditions (n=3 each): phosphatebufferedsaline (PBS; control), pancreatic digested-casein (PD-casein; negative control), PT-gliadin (positive control), non-specific IgY with PT-gliadin, and anti-wheat gliadin IgY with PT-gliadin at a ratio of 1:6,000, 1:3,000 and 1:1,500. Caco-2 monolayers were then evaluated for effects of gliadin and/or anti-wheat gliadin IgY after 24 h exposure. Enzyme-linked immunosorbent assay (ELISA) was used to quantify anti-inflammatory markers (TNF-α and IL-1β) 5 days after cells were exposed to PT-gliadin and/or anti-wheat gliadin IgY.
Among other conditions, anti-wheat gliadin IgY at a ratio of 1:3,000 (anti-gliadin IgY: PT-gliadin) significantlyprevented gliadin toxicity on Caco-2 by maintaining intestinal integrity, inhibiting phenol red permeation, and inhibiting gliadin absorption and production of proinflammatory cytokines (TNF-α and IL-1β) as compared to PT-gliadin stimulated cultures (P < 0.05).
The anti-wheat gliadin IgY antibody produced in this study has proved to inhibit absorption of gliadin and gliadin-induced inflammatory response in Caco2 cell culture model of CD. Anti-gliadin IgY, therefore has potential to be used as an oral passive antibody therapy to treat CD.
Celiac disease; Gliadin; Immunoglobulin Y; Intestinal integrity; Cytokines
Pertussis (whooping cough) remains a public health problem despite extensive vaccination strategies. Better understanding of the host-pathogen interaction and the detailed B. pertussis (Bp) target recognition pattern will help in guided vaccine design. We characterized the specific epitope antigen recognition profiles of serum antibodies (‘the reactome’) induced by whooping cough and B. pertussis (Bp) vaccines from a case–control study conducted in 1996 in infants enrolled in a Bp vaccine trial in Sweden (Gustafsson, NEJM, 1996, 334, 349–355).
Sera from children with whooping cough, vaccinated with Diphtheria Tetanus Pertussis (DTP) whole-cell (wc), acellular 5 (DPTa5), or with the 2 component (a2) vaccines and from infants receiving only DT (n = 10 for each group) were tested with high-content peptide microarrays containing 17 Bp proteins displayed as linear (n = 3175) peptide stretches. Slides were incubated with serum and peptide-IgG complexes detected with Cy5-labeled goat anti-human IgG and analyzed using a GenePix 4000B microarray scanner, followed by statistical analysis, using PAM (Prediction Analysis for Microarrays) and the identification of uniquely recognized peptide epitopes.
367/3,085 (11.9%) peptides were recognized in 10/10 sera from children with whooping cough, 239 (7.7%) in DTPwc, 259 (8.4%) in DTPa5, 105 (3.4%) DTPa2, 179 (5.8%) in the DT groups. Recognition of strongly recognized peptides was similar between whooping cough and DPTwc, but statistically different between whooping cough vs. DTPa5 (p < 0.05), DTPa2 and DT (p < 0.001 vs. both) vaccines. 6/3,085 and 2/3,085 peptides were exclusively recognized in (10/10) sera from children with whooping cough and DTPa2 vaccination, respectively. DTPwc resembles more closely the whooping cough reactome as compared to acellular vaccines.
We could identify a unique recognition signature common for each vaccination group (10/10 children). Peptide microarray technology allows detection of subtle differences in epitope signature responses and may help to guide rational vaccine development by the objective description of a clinically relevant immune response that confers protection against infectious pathogens.
Electronic supplementary material
The online version of this article (doi:10.1186/s12865-015-0090-3) contains supplementary material, which is available to authorized users.
Whooping cough; Vaccine; Immune response; Peptide microarrays
Programmed cell death 1 (PD-1) is a key cell-surface receptor of CD28 superfamily that triggers inhibitory pathways to attenuate T-cell responses and promote T-cell tolerance. As a crucial role in tumor immunity, PD-1 has been a focus of studies in anti-cancer therapy. It has been approved that tumors could exploit PD-1-dependent immune suppression for immune evasion. Considering the wide use of glucocorticoids (GCs) in anti-cancer therapy and their immunosuppressive effects, we explored whether GCs could influence the expression of PD-1.
In our study, we used dexamethasone (DEX) as a model glucocorticoid and demonstrated that DEX could enhance PD-1 expression in a dose-dependent manner. The effects were completely inhibited by the glucocorticoid receptor (GR) antagonist mifepristone (RU486), indicating that the effect of DEX on PD-1 is mediated through GR. We further found the sensitivity to DEX-induced upregulation of PD-1 expression had a significant difference between different T cell subsets, with memory T cells more susceptible to this effect. We also showed that DEX could suppress T cell functions via inhibition of cytokines production such as IL-2, IFN-γ, TNF-α and induction of apoptosis of T cells.
Our findings suggest a novel way by which DEX suppress the function of activated T lymphocytes by enhancing expression of PD-1 and provide an insight into the optimum clinical application of GCs.
PD-1; Glucocorticoids; Naïve T cells; Memory T cells
Tuberculosis (TB) remains a serious human health problem that affects millions of people in the world. Understanding the biology of Mycobacterium tuberculosis (Mtb) is essential for tackling this devastating disease. Mtb possesses a very complex cell envelope containing a variety of lipid components that participate in the establishment of the infection. We have previously demonstrated that di-O-acylated trehalose (DAT), a non-covalently linked cell wall glycolipid, inhibits the proliferation of T lymphocytes and the production of cytokines.
In this work we show that DAT and the closely related tri-O-acylated trehalose (TAT) inhibits nitric oxide (NO) production and the inducible nitric oxide synthase (iNOS) expression in macrophages (MØ).
These findings show that DAT and TAT are cell-wall located virulence factors that downregulate an important effector of the immune response against mycobacteria.
Tuberculosis; Glycolipids; Nitric oxide; iNOS
Phenotype of chronic rhinosinusitis (CRS) may be an important determining factor of the efficacy of anti-inflammatory treatments. Although both glucocorticoids and macrolide antibiotics have been recommended for the treatment of CRS, whether they have different anti-inflammatory functions for distinct phenotypic CRS has not been completely understood. The aim of this study is to compare the anti-inflammatory effects of clarithromycin and dexamethasone on sinonasal mucosal explants from different phenotypic CRS ex vivo.
Ethmoid mucosal tissues from CRSsNP patients (n = 15), and polyp tissues from eosinophilic (n = 13) and non-eosinophilic (n = 12) CRSwNP patients were cultured in an ex vivo explant model with or without dexamethasone or clarithromycin treatment for 24 h. After culture, the production and/or expression of anti-inflammatory molecules, epithelial-derived cytokines, pro-inflammatory cytokines, T helper (Th)1, Th2 and Th17 cytokines, chemokines, dendritic cell relevant markers, pattern recognition receptors (PRRs), and tissue remodeling factors were detected in tissue explants or culture supernatants by RT-PCR or ELISA, respectively.
We found that both clarithromycin and dexamethasone up-regulated the production of anti-inflammatory mediators (Clara cell 10-kDa protein and interleukin (IL)-10), whereas down-regulated the production of Th2 response and eosinophilia promoting molecules (thymic stromal lymphopoietin, IL-25, IL-33, CD80, CD86, OX40 ligand, programmed cell death ligand 1, CCL17, CCL22, CCL11, CCL5, IL-5, IL-13, and eosinophilic cationic protein) and Th1 response and neutrophilia promoting molecules (CXCL8, CXCL5, CXCL10, CXCL9, interferon-γ, and IL-12), from sinonasal mucosa from distinct phenotypic CRS. In contrast, they had no effect on IL-17A production. The expression of PRRs (Toll-like receptors and melanoma differentiation-associated gene 5) was induced, and the production of tissue remodeling factors (transforming growth factor-β1, epidermal growth factor, basic fibroblast growth factor, platelet derived growth factor, vascular endothelial growth factor, and matrix metalloproteinase 9) was suppressed, in different phenotypic CRS by dexamethasone and clarithromycin in comparable extent.
Out of our expectation, our explant model study discovered herein that glucocorticoids and macrolides likely exerted similar regulatory actions on CRS and most of their effects did not vary by the phenotypes of CRS.
Chronic rhinosinusitis; Nasal polyps; Clarithromycin; Dexamethasone; Eosinophil; Inflammation; Tissue remodeling; Innate immunity
Lung inflammation is a major consequence of the systemic inflammatory response caused by severe sepsis. Increased migration of γδ T lymphocytes into the lungs has been previously demonstrated during experimental sepsis; however, the involvement of the γδ T cell subtype Vγ4 has not been previously described.
Severe sepsis was induced by cecal ligation and puncture (CLP; 9 punctures, 21G needle) in male C57BL/6 mice. γδ and Vγ4 T lymphocyte depletion was performed by 3A10 and UC3-10A6 mAb i.p. administration, respectively. Lung infiltrating T lymphocytes, IL-17 production and mortality rate were evaluated.
Severe sepsis induced by CLP in C57BL/6 mice led to an intense lung inflammatory response, marked by the accumulation of γδ T lymphocytes (comprising the Vγ4 subtype). γδ T lymphocytes present in the lungs of CLP mice were likely to be originated from peripheral lymphoid organs and migrated towards CCL2, CCL3 and CCL5, which were highly produced in response to CLP-induced sepsis. Increased expression of CD25 by Vγ4 T lymphocytes was observed in spleen earlier than that by αβ T cells, suggesting the early activation of Vγ4 T cells. The Vγ4 T lymphocyte subset predominated among the IL-17+ cell populations present in the lungs of CLP mice (unlike Vγ1 and αβ T lymphocytes) and was strongly biased toward IL-17 rather than toward IFN-γ production. Accordingly, the in vivo administration of anti-Vγ4 mAb abrogated CLP-induced IL-17 production in mouse lungs. Furthermore, anti-Vγ4 mAb treatment accelerated mortality rate in severe septic mice, demonstrating that Vγ4 T lymphocyte play a beneficial role in host defense.
Overall, our findings provide evidence that early-activated Vγ4 T lymphocytes are the main responsible cells for IL-17 production in inflamed lungs during the course of sepsis and delay mortality of septic mice.
Electronic supplementary material
The online version of this article (doi:10.1186/s12865-015-0098-8) contains supplementary material, which is available to authorized users.
γδ T cell; Interleukin-17; Chemokines; Sepsis
Abnormal immune function is often an underlying component of illness pathophysiology and symptom presentation. Functional and phenotypic immune-related alterations may play a role in the obscure pathomechanism of Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME). The objective of this study was to investigate the functional ability of innate and adaptive immune cells in moderate and severe CFS/ME patients. The 1994 Fukuda criteria for CFS/ME were used to define CFS/ME patients. CFS/ME participants were grouped based on illness severity with 15 moderately affected (moderate) and 12 severely affected (severe) CFS/ME patients who were age and sex matched with 18 healthy controls. Flow cytometric protocols were used for immunological analysis of dendritic cells, monocytes and neutrophil function as well as measures of lytic proteins and T, natural killer (NK) and B cell receptors.
CFS/ME patients exhibited alterations in NK receptors and adhesion markers and receptors on CD4+T and CD8+T cells. Moderate CFS/ME patients had increased CD8+ CD45RA effector memory T cells, SLAM expression on NK cells, KIR2DL5+ on CD4+T cells and BTLA4+ on CD4+T central memory cells. Moderate CFS/ME patients also had reduced CD8+T central memory LFA-1, total CD8+T KLRG1, naïve CD4+T KLRG1 and CD56dimCD16− NK cell CD2+ and CD18+CD2+. Severe CFS/ME patients had increased CD18+CD11c− in the CD56dimCD16− NK cell phenotype and reduced NKp46 in CD56brightCD16dim NK cells.
This research accentuated the presence of immunological abnormalities in CFS/ME and highlighted the importance of assessing functional parameters of both innate and adaptive immune systems in the illness.
Electronic supplementary material
The online version of this article (doi:10.1186/s12865-015-0101-4) contains supplementary material, which is available to authorized users.
Chronic fatigue syndrome; Natural killer cell; Receptors; CD8+T Cell
Polysaccharopeptide (PSP), isolated from Coriolus versicolor COV-1 strain, is a protein-bound polysaccharide widely used as immunoadjuvant for cancer immunotherapy. Although the immunomodulatory activity of PSP has been well established, the precise molecule mechanisms of its biological activity have yet to be fully elucidated.
In the present study, we first investigated the immunomodulatory activity of PSP in peritoneal macrophages from C57BL/10J (TLR4+/+) and C57BL/10ScCr (TLR4-/-) mice carrying a defective toll-like receptor-4 (TLR4) gene and then evaluated PSP for its effect on tumor inhibition rates and the immune organ index in above two different strains of mice. In addition, PSP were also evaluated for its activation of TLR4, TLR4-downstream molecules (TRAF6, NF-κB and AP-1) in spleens of tumor-bearing C57BL/10J (TLR4+/+) and C57BL/10ScCr (TLR4-/-) mice.
The results showed that PSP had adjuvant activities in stimulating expressions of cytokines as well as TLR4, TRAF6, phosphorylation of NF-κB p65 transcription factors and phosphorylation of c-Jun (a component of the transcription factor AP-1) in peritoneal macrophages from C57BL/10J (TLR4+/+) mice but not from C57BL/10ScCr (TLR4-/-) mice. In vivo PSP as well as Adriamycin (ADM) decreased the mean weights of tumors compared with normal saline and PSP increased thymus index and spleen index relative to ADM in tumor-bearing C57BL/10J (TLR4+/+) mice but not in C57BL/10ScCr (TLR4-/-) mice.
We demonstrated that PSP activates peritoneal macrophages in vitro via TLR4 signaling pathway and PSP functions its immunoregulatory effect in vivo also via TLR4 signaling pathway. These data strongly suggest TLR4 signaling pathway is involved in PSP-mediated immunomodulatory activities.
Polysaccharopeptide; TLR4; TLR4 signaling pathway; Immunomodulatory
Technical feasibility of RNA quantification by real time RT-PCR has led to enormous utilization of this method. However, real time PCR results need to be normalized due to the high sensitivity of the method and also to eliminate technical variation. Normalization against a reference gene that is constitutively transcribed and has minimum variation among samples is the ideal method. Nevertheless, many studies have shown that there is no general reference gene(s) with ideal characteristics and candidate reference genes should be tested before being used as a “normalizer” in each study.
The current study investigated the effects of previous exposure of the host to experimental test antigens and culturing time on the expression of 11 candidate genes when blood mononuclear cells (BMCs) were cultured and treated in-vitro by hen egg white lysozyme, Candida albicans extract and a mitogen. Mononuclear cells were isolated and cultured from 12 bovine blood samples representing 3 different immunological statuses. The expression of candidate housekeeping genes were measured by real-time RT-PCR at 4 and 24 hours post culture. The expression of candidate genes were first compared between the two time points in untreated samples. Constitutively expressed genes were further tested in linear mixed effects models to examine the effect of previous host exposure and in-vitro treatments.
Our findings showed that the expression of the most common reference genes, β-actin, and Glyceraldehydes-3-phosphate dehydrogenase (GAPDH), are significantly decreased at 24 hours after culturing BMCs, even without any treatment. The effect of culturing time was also significantly influenced the expression of 18s ribosomal RNA, β2-microglobulin, Tyrosine 3-monooxygenase/tryptophan 5-monoxygenase activation protein, zeta polypeptide (YWHAZ) in BMCs. Only the expression of C-terminal binding protein 1 (CTBP1) and RAD50 among all tested genes were consistent after treatment of cultured BMCs with C. albicans whole yeast extract and Hen Egg White Lysozyme (HEWL), respectively. In addition, expressions of CTBP1, and RAD50 were independent from previous exposure of the host to the antigen.
The results of this study demonstrated inconsistent expression of commonly used reference genes in untreated cultured BMCs over time. As this condition applies to negative controls in real time RT-PCR study designs, normalization against these genes can largely deceive the outcome, especially in kinetic studies. Moreover, the potential effects of immunological memory on the expression of reference genes should be considered if BMCs are collected from different individuals under different environmental conditions and if these cells are treated in-vitro by an antigen.
Reference gene; Real time RT-PCR; Blood mononuclear cells
Retinoic acid receptor-related orphan receptor gamma t (RORγt) is the master regulator of Th17 cell differentiation, which plays a critical role in the pathology of several autoimmune diseases. By directing Th17 cells function, RORγt could be a potential target for drug development for Th17 related autoimmune disease.
A Jurkat cell-based reporter assay system was used for screening RORγt inhibitors from a drug-like chemical library, following with mouse Th17 cells differentiation study to identify the effect of targeted compounds in primary T cells. 293T cell-based reporter assay was conducted to determine the cell specificity, and MTT assay was performed to determine the cell toxicity of those compounds.
In this study, we identified four lead compounds that suppressed RORγt activity, Th17 differentiation and IL-17A secretion. These candidates displayed inhibition ability on RORγt activity in T cell derived Jurkat cell, but not in 293 T cell, which indicated the restricted effects of these compounds to other cells or tissues. Futhermore, our results demonstrated that these candidates exhibited more robust inhibitory on IL-17 F transcription expression than IL-17A, which is different from one reported compound, SR1001, that mainly suppressed IL-17A, rather than IL-17 F production.
Our study discovered four novel compounds that inhibited RORγt activity and Th17 function, which indicates their potential in therapeutic application of Th17 related autoimmune disorders.
RORγt; Th17 cell; Autoimmune disease; IL-17A
Neuromyelitis optica (NMO) is an autoimmune disorder of the central nervous system, which is characterized by autoantibodies directed against the water channel aquaporin-4 (AQP4). As one of the main water regulators in the central nervous system, APQ4 is supposed to be involved in the dynamics of brain edema. Cerebral edema seriously affects clinical outcome after ischemic stroke; we therefore aimed to investigate whether NMO-antibodies may exert the same functional effects as an AQP4-inhibitor in-vivo in acute ischemic stroke.
Sixteen male Wistar rats were randomized into two groups twice receiving either purified NMO-IgG or immune globulin from healthy controls, 24 hours and 30 minutes before middle cerebral artery occlusion (MCAO) was performed. T2-weighted MRI was carried out 24 hours after MCAO.
MRI-examination showed a significant increase of infarct size in relation to the cerebral hemisphere volume with NMO-IgG treated animals (27.1% ± 11.1% vs. 14.3% ± 7.2%; p < 0.05) when corrected for the space-occupying effect of vasogenic edema formation and similar results without edema correction (34.4% ± 16.4% vs. 17.5% ± 9.3%; p < 0.05). Furthermore, T2-RT revealed a significant increase in cortical brain water content of the treatment group (19.5 ms ± 9.7 ms vs. 9.2 ms ± 5.2 ms; p < 0.05).
These results support the functional impact of NMO-antibodies and also offer an in-vivo-applicable animal model to investigate the properties of AQP4 in ischemic stroke.
Aquaporin-4; Cerebral edema; Infarct size; Neuromyelitis optica; Stroke animal model
Scavenger receptor A (SRA) is expressed predominantly in phagocytic cells playing an essential role in the host immune defense against invading microorganisms. Our previous study reported the presence of SRA in a soluble form in patients with infection of hepatitis B viruses (HBV). However, the association of soluble SRA with stages of HBV infection and the immune response induced by HBV is not fully determined.
In this study, we detected soluble SRA in serum from 29 chronic hepatitis B (CHB) patients, 28 chronic HBV carriers in the immune tolerant (IT) stage, 33 in the HBeAg-negative inactive carrier (IC) stage, and 22 healthy controls (HCs), respectively. We further analyzed the correlation of detected soluble SRA to inflammation and serum viral load. In addition, we investigated the regulatory role of soluble SRA in T cell activation, especially in CD8+ T cell response to HBV peptide.
We demonstrated that Median levels of serum soluble SRA in CHB and IT patients were significantly higher than those of IC patients and HCs. Additionally, the concentrations of soluble SRA were negatively correlated with alanine transaminase levels in CHB patients. We also found that serum concentration of SRA was decreased during telbivudine treatment. Expressed SRA extracellular domain suppressed HBV core peptide-stimulated interferon-γ and tumor necrosis factor-α production in CD8+ T cells, and it bound to T cells in a higher frequency in CHB patients than in HCs. Furthermore, we observed that naïve human T cells stimulated by anti-CD3 and CD28 antibodies in the presence of the recombinant SRA protein had reduced activation and proliferation.
In summary, we determined the level of soluble SRA in different stages of CHB patients. SRA might inhibit T cell proliferation and activation as a soluble form. These results not only revealed a previously unknown feature of soluble SRA in CHB patients but also provided broad understanding of SRA in T cell activation.
Electronic supplementary material
The online version of this article (doi:10.1186/s12865-015-0088-x) contains supplementary material, which is available to authorized users.
Scavenger receptor A; Chronic hepatitis B; T cell activation;
Multiple sclerosis (MS) is an autoimmune disease in which dysregulated immune cells attack myelin in the central nervous system (CNS), leading to irreversible neuronal degeneration. Our previous studies have demonstrated that epidermal fatty acid binding protein (E-FABP), widely expressed in immune cells, in particular in dendritic cells (DCs) and T lymphocytes, fuels the overactive immune responses in the mouse model of experimental autoimmune encephalomyelitis (EAE).
In the present study, we conducted an intensive computational docking analysis to identify novel E-FABP inhibitors for regulation of immune cell functions and for treatment of EAE.
We demonstrate that compound [2-(4-acetylphenoxy)-9,10-dimethoxy-6,7-dihydropyrimido[6,1-a]isoquinolin-4-one; designated as EI-03] bound to the lipid binding pocket of E-FABP and enhanced the expression of peroxisome proliferator-activating receptor (PPAR) γ. Further in vitro experiments showed that EI-03 regulated DC functions by inhibition of TNFα production while promoting IL-10 secretion. Moreover, EI-03 treatment counterregulated T cell balance by decreasing effector T cell differentiation (e.g. Th17, Th1) while increasing regulatory T cell development. Most importantly, mice treated with this newly identified compound exhibited reduced clinical symptoms of EAE in mouse models.
Taken together, we have identified a new compound which displays a potential therapeutic benefit for treatment of MS by targeting E-FABP.
Fatty acid binding protein; Antigen present cells; T lymphocytes; EAE
Immunological memory is the ability of the immune system to respond more rapidly and effectively to previously encountered pathogens, a key feature of adaptive immunity. The capacity of memory T cells to “remember” previous cellular responses to specific antigens ultimately resides in their unique patterns of gene expression. Following re-exposure to an antigen, previously activated genes are transcribed more rapidly and robustly in memory T cells compared to their naïve counterparts. The ability for cells to remember past transcriptional responses is termed “adaptive transcriptional memory”.
Recent global epigenome studies suggest that epigenetic mechanisms are central to establishing and maintaining transcriptional memory, with elegant studies in model organisms providing tantalizing insights into the epigenetic programs that contribute to adaptive immunity. These epigenetic mechanisms are diverse, and include not only classical acetylation and methylation events, but also exciting and less well-known mechanisms involving histone structure, upstream signalling pathways, and nuclear localisation of genomic regions.
Current global health challenges in areas such as tuberculosis and influenza demand not only more effective and safer vaccines, but also vaccines for a wider range of health priorities, including HIV, cancer, and emerging pathogens such as Ebola. Understanding the multi-layered epigenetic mechanisms that underpin the rapid recall responses of memory T cells following reactivation is a critical component of this development pathway.
Transcriptional memory; Memory T cells; Epigenetics; Post-translational modification; Histone variant exchange; PKC-theta; Yeast
HIV-infected long-term non-progressor (LTNP) subjects can prevent viral replication and may harbor useful information for the development of both antibody and active vaccination treatments. In this study we used LTNP sera to examine the epitopes presented to the gp160 protein, and from this procedure we hope to elucidate potential biomarkers pertaining to the level of resistance a patient may have in developing AIDS after infection with HIV. We used five clinical sera samples from LTNP patients to identify common epitopes by ELISA; peptides with high binding to sera were selected and analyzed for conservation among HIV clades. Antibodies were generated against one identified epitope using a chimeric peptide in BALB/c mice, and both the sera from these mice and LTNP sera were tested for viral inhibition capabilities.
A monoclonal antibody, CL3, against one identified epitope was used to compare these epitopes neutralizing capability. LTNP sera was also studied to determine chemokine/cytokine changes in these patients. The sera from LTNP patients 2, 3, 4, and 5 were identified as having the highest titers, and also significantly inhibited syncytia formation in vitro. Finally, the protein cytokine array demonstrated that I-309 and IGFBP-1 decreased in LTNPs, but levels of TIMP-1 and NAP-2 increased significantly.
Our results indicate that the use of LTNP samples may be a useful for identifying further anti-viral epitopes, and may be a possible predictor for determining if patients show higher resistances of converting the HIV infection to AIDS.
HIV; AIDS; LTNP; Long-term non-progressor; Monoclonal antibody; Epitope; Virus
Blood platelets are first aimed at ensuring primary hemostasis. Beyond this role, they have been acknowledged as having functions in the maintenance of the vascular arborescence and, more recently, as being also innate immune cells, devoted notably to the detection of danger signals, of which infectious ones. Platelets express pathogen recognition receptors that can sense bacterial and viral moieties. Besides, several molecules that bind epithelial or sub-endothelial molecules and, so forth, are involved in hemostasis, happen to be able to ligate viral determinants, making platelets capable of either binding viruses or even to be infected by some of them. Further, as platelets express both Fc-receptors for Ig and complement receptors, they also bind occasionally virus-Ig or virus-Ig-complement immune complexes. Interplays of viruses with platelets are very complex and viral infections often interfere with platelet number and functions. Through a few instances of viral infections, the present review aims at presenting some of the most important interactions from pathophysiological and clinical points of view, which are observed between human viruses and platelets.
Platelets; Receptors; Viruses; Infection; Hemostasis
Experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, is induced by immunization of mice with myelin oligodendrocytic glycoprotein (MOG35-55) injections, and after 9 days, mice develop behavioral signs of chronic progressive EAE. Proliferation of T and B cells located in peripheral lymph tissues such as spleen and inguinal lymph nodes of C57BL/6J mice are stimulated. The opioid growth factor-opioid growth factor receptor (OGF-OGFr) axis has been shown to effectively limit progression of chronic EAE when mice are treated at the time of induction or at time of established disease. In addition to repressed behavioral profiles, spinal cord neuropathology is diminished in mice treated with OGF or low dosages of naltrexone (LDN). However, there is little or no information on peripheral lymphocyte dynamics following immunization of mice with MOG antigen and treatment with OGF or LDN.
Six-week old female mice were immunized with MOG35-55 and were injected intraperitoneally with OGF or a low dosage of naltrexone (LDN) beginning at the time of immunization; saline-injected immunized mice served as controls. Normal mice received saline for all injections. Periodically over a 2 week period, spleens and inguinal lymph nodes were removed, total lymphocytes counted, and subpopulations of CD4+ and CD8+ specific T-cells, as well as B lymphocytes, were determined by flow cytometry. On day 15 of treatment, lumbar spinal cord tissue was removed; CNS lymphocytes isolated, and assayed for Th1, Th2, and Th17 markers by flow cytometry.
Exogenous OGF or endogenous OGF following LDN suppressed T and B lymphocyte proliferation in the spleen and inguinal lymph nodes of MOG-immunized mice. Suppression of peripheral immune cell CD4+ and CD8+ T cell proliferation at 5 and 12 days correlated with reductions in clinical behavior. EAE mice treated with OGF for 15 days displayed elevated Th1 and Th17 cells; no subpopulations of Th2-specific T cells were noted.
OGF or LDN repress proliferation of CD4+ and CD8+T cells and B220+ B lymphocytes in the spleen and lymph nodes of immunized mice within a week of immunization. These data provide novel mechanistic pathways underlying the efficacy of OGF and LDN therapy for MS.
Low dose naltrexone; OGF; T cell proliferation; Experimental autoimmune encephalomyelitis; Multiple sclerosis
Monocytes and macrophages produce interleukin (IL)-10, an immunoregulatory cytokine and a potent therapeutic tool for immune disorders. Augmentation of IL-10 production with a concomitant reduction of proinflammatory cytokines in macrophages in vitro is attained by doubly stimulating the cells with a toll-like receptor ligand and immunoglobulin (Ig)G immune complexes, a response known as that of regulatory (or alternatively activated/M2) macrophages. However, it has not been explored sufficiently how such a regulatory response could be exploited for anti-inflammation. Our objective is to find a potential way or condition for augmenting IL-10 by monocytes/macrophages in vivo and in vitro.
We show that platelets, when they are opsonized with IgG, can convert human peripheral blood circulating monocytes to IL-10-producing regulatory monocytes in vitro and also in a murine in vivo model. Co-culturing of platelets and monocytes in the presence of anti-integrin IgG and a bacterial lipopolysaccharide augmented IL-10 production via a direct interaction between platelets and monocytes. This novel way of enhancing IL-10 was mediated by activating-type Fc receptors for IgG.
These findings indicate that the IgG-bound platelet-induced conversion of monocytes to regulatory cells might provide a novel strategy for controlling inflammation.
Electronic supplementary material
The online version of this article (doi:10.1186/s12865-015-0086-z) contains supplementary material, which is available to authorized users.
Regulatory response; IL-10; Platelet; Fc receptor; Monocyte
Hantaviruses are emerging zoonotic pathogens which cause hemorrhagic fever with renal syndrome, an immune-mediated pathogenesis is discussed. The aim of the present study was to investigate the role of TGF-β expression in acute hantavirus infection.
We retrospectively studied 77 patients hospitalised with acute Puumala infection during a hantavirus epidemic in Germany in 2012. Hantavirus infection was confirmed by positive anti-Puumala hantavirus IgG and IgM. Plasma levels of transforming growth factor (TGF)-β1 and TGF-β2 were analysed. Based on glomerular filtration rate on admission, patients were divided in mild and severe course of disease. Puumala virus RNA was detected by PCR amplification of the viral L segment gene. Out of 77 Puumala virus infected patients, 52 (68%) were male. A seasonal distribution was detected in our cohort with a peak in summer 2012, the highest incidence was observed in the age group of 30–39 years. Puumala virus RNA was detectable in 4/77 cases. Patients with severe disease had a significant longer hospital stay than patients with mild disease (6.2 vs 3.6 days). Thrombocyte count (186 vs 225 per nl), serum TGF-β1 (74 vs 118 ng/l) and TGF-β2 (479 vs 586 pg/l) were significantly lower in severe compared to mild disease. However, C-reactive protein (CRP) was significantly higher in patients with severe disease (62 vs 40 mg/l). TGF-β1/Cr was the most sensitive and specific marker associated with renal dysfunction.
High serum CRP and low serum TGF-β in the early phase of hantavirus infection is associated with a severe course of disease. Our results support the hypothesis of an immune-mediated pathogenesis in hantavirus infection.
Hantavirus; Puumala; Transforming growth factor; TGF; Severe disease
Proof of the Germ theory of disease and acceptance of Koch’s postulates in the late 1890’s launched the fields of microbial pathogenesis and infectious diseases and provided the conceptual framework that has guided thought and research in these fields. A central tenet that emerged from studies with microbes that fulfilled Koch’s postulates was that microbes that caused disease had characteristics that allowed them to do so, with the corollary that microbes that did not cause disease lacked disease-causing determinants. This observation, which held true for many diseases that were known to cause disease in the late 19th century, such as toxin-producing and encapsulated bacteria, led to the view that the ability to cause disease rested with microbes and reflected the activity of specific determinants, or virulence factors. With the dawn of the 20th century, efforts to neutralize virulence factors were under development and ultimately translated into anti-microbial therapy in the form of antibodies targeted to toxins and polysaccharide capsules. However, the 20th century progressed, antibiotics were identified and developed as therapy for infectious diseases while other medical advances, such as specialized surgeries, intensive care units, intravenous catheters, and cytotoxic chemotherapy became commonplace in resourced nations. An unintended consequence of many of these advances was that they resulted in immune impairment. Similarly, HIV/AIDS, which emerged in the late 1970’s also produced profound immune impairment. Unexpectedly, the prevailing view that microbes were the sole perpetrators of virulence was untenable. Microbes that were rarely if ever associated with disease emerged as major causes of disease in people with impaired immunity. This phenomenon revealed that available explanations for microbial infectiveness and virulence were flawed. In this review, we discuss the question ‘what is infectiveness’ based on the tenets of the Damage-response framework.
Malaria remains a major worldwide public health problem with ~207 million cases and ~627,000 deaths per year, mainly affecting children under five years of age in Africa. Recent efforts at elaborating a genetic architecture of malaria have focused on severe malaria, leading to the identification of two new genes and confirmation of previously known variants in HBB, ABO and G6PD, by exploring the whole human genome in genome-wide association (GWA) studies. Molecular pathways controlling phenotypes representing effectiveness of host immunity, notably parasitemia and IgG levels, are of particular interest given the current lack of an efficacious vaccine and the need for new treatment options.
We propose a global causal framework of malaria phenotypes implicating progression from the initial infection with Plasmodium spp. to the development of the infection through liver and blood-stage multiplication cycles (parasitemia as a quantitative trait), to clinical malaria attack, and finally to severe malaria. Genetic polymorphism may control any of these stages, such that preceding stages act as mediators of subsequent stages. A biomarker of humoral immunity, IgG levels, can also be integrated into the framework, potentially mediating the impact of polymorphism by limiting parasitemia levels. Current knowledge of the genetic basis of parasitemia levels and IgG levels is reviewed through key examples including the hemoglobinopathies, showing that the protective effect of HBB variants on malaria clinical phenotypes may partially be mediated through parasitemia and cytophilic IgG levels. Another example is the IgG receptor FcγRIIa, encoded by FCGR2A, such that H131 homozygotes displayed higher IgG2 levels and were protective against high parasitemia and onset of malaria symptoms as shown in a causal diagram.
We thus underline the value of parasitemia and IgG levels as phenotypes in the understanding of the human genetic architecture of malaria, and the need for applying GWA approaches to these phenotypes.
Malaria; Genome-wide association study; Parasitemia; Humoral immunity
Sepsis is a dynamic infectious disease syndrome characterized by dysregulated inflammatory responses.
Despite decades of research, improvements in the treatment of sepsis have been modest. These limited advances are likely due, in part, to multiple factors, including substantial heterogeneity in septic syndromes, significant knowledge gaps in our understanding of how immune cells function in sepsis, and limitations in animal models that accurately recapitulate the human septic milieu. The goal of this brief review is to describe current challenges in understanding immune cell functions during sepsis. We also provide a framework to guide scientists and clinicians in research and patient care as they strive to better understand dysregulated cell responses during sepsis.
Additional, well-designed translational studies in sepsis are critical for enhancing our understanding of the role of immune cells in sepsis.
Sepsis; Neutrophils; Dendritic cells; Infection; Inflammation; Immunity
Vaccination has been a major advance for health care, allowing eradication or reduction of incidence and mortality of various infectious diseases. However, there are major pathogens, such as Human Immunodeficiency Virus (HIV) or the causative agent of malaria, for which classical vaccination approaches have failed, therefore requiring new vaccination strategies. The development of new vaccine strategies relies on the ability to identify the challenges posed by these pathogens. Understanding the pathogenesis and correlates of protection for these diseases, our ability to accurately direct immune responses and to vaccinate specific populations are such examples of these roadblocks. In this respect, the use of a robust, cost-effective and predictive animal model that recapitulates features of both human infection and vaccination is currently a much-needed tool. We discuss here the major limitations faced by modern vaccinology and notably, the development of humanized mice for assessing the immune system, along with their potential as vaccine models.
Vaccination; Humanized mouse model; Correlates of protection; Pathogens; Immune response; Route of administration; Adjuvants