IFN-gamma-inducible protein 10 (IP-10; CXCL10)-deficient mice reveal a role for IP-10 in effector T cell generation and trafficking

Depletion of plasmacytoid dendritic cells inhibits tumor growth and prevents bone metastasis of breast cancer cells

Elevated levels of plasmacytoid dendritic cells (pDC) have been reported in breast cancer patients, but the significance remains undefined. Using three immunocompetent mouse models of breast cancer bone metastasis, we identified a key role for pDC in facilitating tumor growth through immunosuppression and aggressive osteolysis. Following infiltration of macrophages upon breast cancer dissemination, there was a steady increase in pDC within the bone, which resulted in a sustained Th2 response along with elevated levels of regulatory T cells and myeloid-derived suppressor cells. Subsequently, pDC and CD4(+) T cells, producing osteolytic cytokines, increased with tumor burden, causing severe bone damage. Microcomputed tomography and histology analyses of bone showed destruction of femur and tibia. The therapeutic significance of this finding was confirmed by depletion of pDC, which resulted in decreased tumor burden and bone loss by activating tumor-specific cytolytic CD8(+) T cells and decreasing suppressor cell populations. Thus, pDC depletion may offer a novel adjuvant strategy to therapeutically influence breast cancer bone metastasis.

Pretreatment circulating serum cytokines associated with follicular and diffuse large B-cell lymphoma: a clinic-based case-control study

BACKGROUND

Abnormal immune function is a key factor in predisposition to non-Hodgkin lymphoma (NHL). We evaluated the association of 30 cytokines individually and as a profile with diffuse large B-cell (DLBCL) and follicular (FL) lymphomas.

METHODS

We used a multiplexed assay to measure 30 cytokine concentrations in pre-treatment serum in a case-control study of 234 FL, 188 DLBCL, and 400 control participants. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for age and sex, and polytomous regression was used to evaluate heterogeneity between FL and DLBCL. Principal components analysis (PCA) was used to assess cytokine profiles associated with FL and DLBCL.

RESULTS

In single cytokine modeling, we found that 12 of the 30 circulating serum cytokines were significantly (P<0.05) associated with FL and/or DLBCL after accounting for multiple testing (q<0.05). Soluble IL-2R (sIL-2R) had the strongest association with both FL (OR=6.0 for highest versus lowest tertile, 95% CI 3.8-9.5; p-trend=1.8 × 10(-21)) and DLBCL (OR=7.6, 95% CI 4.5-13.1; p-trend=7.2 × 10(-20)). IL1RA and IL-12p40 also showed similar associations for DLBCL and FL. In contrast, HGF, MIG, and MIP-1α had a stronger association with DLBCL compared to FL, and IL-6, IL-8, IL-10, IFN-γ, IP-10, and VEGF were only statistically significantly associated with DLBCL after accounting for multiple testing. However, in PCA modeling, a cytokine profile based on sIL-2R, IL-1RA, MIG, IP-10, IL-8, and IL-12p40 explained most of the variability between controls and both FL and DLBCL.

CONCLUSIONS

We identified some cytokines unique to DLBCL, but overall cytokine associations were more similar than distinct for DLBCL and FL. While these data are limited by concerns of reverse causality, they do suggest cytokines and cytokine profiles that can be prioritized in future studies.

Lactocepin secreted by Lactobacillus exerts anti-inflammatory effects by selectively degrading proinflammatory chemokines

The intestinal microbiota has been linked to inflammatory bowel diseases (IBD), and oral treatment with specific bacteria can ameliorate IBD. One bacterial mixture, VSL#3, containing Lactobacillus, Bifidobacterium, and Streptococcus, was clinically shown to reduce inflammation in IBD patients and normalize intestinal levels of IP-10, a lymphocyte-recruiting chemokine, in a murine colitis model. We identified Lactobacillus paracasei prtP-encoded lactocepin as a protease that selectively degrades secreted, cell-associated, and tissue-distributed IP-10, resulting in significantly reduced lymphocyte recruitment after intraperitoneal injection in an ileitis model. A human Lactobacillus casei isolate was also found to encode lactocepin and degrade IP-10. L. casei feeding studies in a murine colitis model (T cell transferred Rag2(-/-) mice) revealed that a prtP-disruption mutant was significantly less potent in reducing IP-10 levels, T cell infiltration and inflammation in cecal tissue compared to the isogenic wild-type strain. Thus, lactocepin-based therapies may be effective treatments for chemokine-mediated diseases like IBD.

Macrophages induce differentiation of plasma cells through CXCL10/IP-10

In tonsils, CD138(+) plasma cells (PCs) are surrounded by CD163(+) resident macrophages (Ms). We show here that human Ms (isolated from tonsils or generated from monocytes in vitro) drive activated B cells to differentiate into CD138(+)CD38(++) PCs through secreted CXCL10/IP-10 and VCAM-1 contact. IP-10 production by Ms is induced by B cell-derived IL-6 and depends on STAT3 phosphorylation. Furthermore, IP-10 amplifies the production of IL-6 by B cells, which sustains the STAT3 signals that lead to PC differentiation. IP-10-deficient mice challenged with NP-Ficoll show a decreased frequency of NP-specific PCs and lower titers of antibodies. Thus, our results reveal a novel dialog between Ms and B cells, in which IP-10 acts as a PC differentiation factor.

Update of immune events in the murine contact hypersensitivity model: toward the understanding of allergic contact dermatitis

Allergic contact dermatitis (ACD) is one of the most common skin diseases, consisting of sensitization and elicitation phases. With the advancement of technology and the discovery of new types of immune cells, our knowledge of the immunological mechanisms of contact hypersensitivity (CHS) as a murine model of ACD has expanded significantly in the past decade. For example, by introducing regulatory T cells, CD4(+) T-helper 17 cells, and Langerin-positive dermal dendritic cells, the initiation and termination mechanism of CHS has been revealed. In addition, the role of mast cells in CHS, long a matter of debate, has become apparent by developing conditional mast cell-deficient mice. Moreover, the role of the innate immunity system, such as that of Toll-like receptor signaling, has made a breakthrough in this field. In this review, we will integrate the recent advancement of immunological mechanisms of both the sensitization and elicitation phases of CHS into the classic view, and we will discuss updated mechanisms on its development and future directions.

Treatment with N-acetyl-seryl-aspartyl-lysyl-proline prevents experimental autoimmune myocarditis in rats

Myocarditis is commonly associated with cardiotropic infections and has been linked to development of autoimmunity. N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is a naturally occurring tetrapeptide that prevents inflammation and fibrosis in hypertension and other cardiovascular diseases; however, its effect on autoimmune-mediated cardiac diseases remains unknown. We studied the effects of Ac-SDKP in experimental autoimmune myocarditis (EAM), a model of T cell-mediated autoimmune disease. This study was conducted to test the hypothesis that Ac-SDKP prevents autoimmune myocardial injury by modulating the immune responses. Lewis rats were immunized with porcine cardiac myosin and treated with Ac-SDKP or vehicle. In EAM, Ac-SDKP prevented both systolic and diastolic cardiac dysfunction, remodeling as shown by hypertrophy and fibrosis, and cell-mediated immune responses without affecting myosin-specific autoantibodies or antigen-specific T cell responses. In addition, Ac-SDKP reduced cardiac infiltration by macrophages, dendritic cells, and T cells, pro-inflammatory cytokines [interleukin (IL)-1α, tumor necrosis factor-α, IL-2, IL-17] and chemokines (cytokine-induced neutrophil chemoattractant-1, interferon-γ-induced protein 10), cell adhesion molecules (intercellular adhesion molecule-1, L-selectin), and matrix metalloproteinases (MMP). Ac-SDKP prevents autoimmune cardiac dysfunction and remodeling without reducing the production of autoantibodies or T cell responses to cardiac myosin. The protective effects of Ac-SDKP in autoimmune myocardial injury are most likely mediated by inhibition of 1) innate and adaptive immune cell infiltration and 2) expression of proinflammatory mediators such as cytokines, chemokines, adhesion molecules, and MMPs.

NK cells regulate CD8+ T cell priming and dendritic cell migration during influenza A infection by IFN-γ and perforin-dependent mechanisms

An effective immune response against influenza A infection depends on the generation of virus-specific T cells. NK cells are one of the first-line defenses against influenza A infection. We set out to delineate the role of NK cells in T cell immunity using a murine model of influenza A infection with A/PR/8/34. We show that early T cell recruitment mainly occurs in the posterior mediastinal lymph node (pMLN). Depletion of NK cells significantly impaired both dendritic cell (DC) and T cell recruitment into the pMLN. A similar reduction of T cell recruitment was observed when migration was blocked by pertussis toxin, suggesting that migration of pulmonary NK cells and DCs regulates cell recruitment to the pMLN. T cell recruitment was dependent on IFN-γ, and transfer of IFN-γ-competent naive NK cells into IFN-γ-/- mice restored T cell recruitment, whereas IFN-γ-deficient NK cells failed to do so. In addition, NK cell depletion reduced the uptake and transport of influenza A virus by DCs, and significantly impaired the virus-specific T cell response. Both IFN-γ-/- and perforin-/- mice showed reduced viral Ag transport by DCs, suggesting that the ability of NK cells to influence virus transport depends on IFN-γ and perforin. In summary, our data suggest that NK cells play a critical role in the initiation and shaping of the T cell response after influenza A infection.

Cytokine and chemokine levels in patients with severe fever with thrombocytopenia syndrome virus

Background

Severe fever with thrombocytopenia syndrome virus (SFTSV), which can cause hemorrhagic fever–like illness, is a newly discovered bunyavirus in China. The pathogenesis of SFTSV infection is poorly understood. However, it has been suggested that immune mechanisms, including cytokines and chemokines, play an important role in disease pathogenesis. In the present study, we investigated host cytokine and chemokine profiles in serum samples of patients with SFTSV infection from Northeast China and explored a possible correlation between cytokine levels and disease severity.

Methods and Principal Findings

Acute phase serum samples from 40 patients, diagnosed with SFTSV infection were included. Patients were divided into two groups – severe or non-severe – based on disease severity. Levels of tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, interleukin-6, interferon (IFN)-γ, IFN- γ-induced protein (IP)-10 and RANTES were measured in the serum samples with commercial ELISAs. Statistical analysis showed that increases in TNF-α, IP-10 and IFN-γ were associated with disease severity.

Conclusions

We suggest that a cytokine-mediated inflammatory response, characterized by cytokine and chemokine production imbalance, might be in part responsible for the disease progression of patients with SFTSV infection.

Cigarette smoke modulates expression of human rhinovirus-induced airway epithelial host defense genes

Human rhinovirus (HRV) infections trigger acute exacerbations of chronic obstructive pulmonary disease (COPD) and asthma. The human airway epithelial cell is the primary site of HRV infection and responds to infection with altered expression of multiple genes, the products of which could regulate the outcome to infection. Cigarette smoking aggravates asthma symptoms, and is also the predominant risk factor for the development and progression of COPD. We, therefore, examined whether cigarette smoke extract (CSE) modulates viral responses by altering HRV-induced epithelial gene expression. Primary cultures of human bronchial epithelial cells were exposed to medium alone, CSE alone, purified HRV-16 alone or to HRV-16+ CSE. After 24 h, supernatants were collected and total cellular RNA was isolated. Gene array analysis was performed to examine mRNA expression. Additional experiments, using real-time RT-PCR, ELISA and/or western blotting, validated altered expression of selected gene products. CSE and HRV-16 each induced groups of genes that were largely independent of each other. When compared to gene expression in response to CSE alone, cells treated with HRV+CSE showed no obvious differences in CSE-induced gene expression. By contrast, compared to gene induction in response to HRV-16 alone, cells exposed to HRV+CSE showed marked suppression of expression of a number of HRV-induced genes associated with various functions, including antiviral defenses, inflammation, viral signaling and airway remodeling. These changes were not associated with altered expression of type I or type III interferons. Thus, CSE alters epithelial responses to HRV infection in a manner that may negatively impact antiviral and host defense outcomes.

HIV delays IFN-α production from human plasmacytoid dendritic cells and is associated with SYK phosphorylation

Plasmacytoid dendritic cells (pDC) are the major producers of type I interferons (IFNs) in humans and rapidly produce IFN-α in response to virus exposure. Although HIV infection is associated with pDC activation, it is unclear why the innate immune response is unable to effectively control viral replication. We systematically compared the effect of HIV, Influenza, Sendai, and HSV-2 at similar target cell multiplicity of infection (M.O.I.) on human pDC function. We found that Influenza, Sendai, HSV-2 and imiquimod are able to rapidly induce IFN-α production within 4 hours to maximal levels, whereas HIV had a delayed induction that was maximal only after 24 hours. In addition, maximal IFN-α induction by HIV was at least 10 fold less than that of the other viruses in the panel. HIV also induced less TNF-α and MIP-1β but similar levels of IP-10 compared to other viruses, which was also mirrored by delayed upregulation of pDC activation markers CD83 and CD86. BDCA-2 has been identified as an inhibitory receptor on pDC, signaling through a pathway that involves SYK phosphorylation. We find that compared to Influenza, HIV induces the activation of the SYK pathway. Thus, HIV delays pDC IFN-α production and pDC activation via SYK phosphorylation, allowing establishment of viral populations.

CD8+ T cells suppress viral replication in the cornea but contribute to VEGF-C-induced lymphatic vessel genesis

HSV-1 is the leading cause of infectious corneal blindness in the industrialized world. CD4(+) T cells are thought to be the major leukocyte population mediating immunity to HSV-1 in the cornea as well as the likely source of immunopathology that reduces visual acuity. However, the role of CD8(+) T cells in immune surveillance of the cornea is unclear. Thus, we sought to evaluate the role of CD8(+) T cells in ocular immunity using transgenic mice in which >98% of CD8(+) T cells are specific for the immunodominant HSV-1 epitope (gBT-I.1). We found a significant reduction in virus, elevation in HSV-specific CD8(+) T cell influx, and more CD8(+) T cells expressing CXCR3 in the cornea of transgenic mice compared with those in the cornea of wild-type controls yet similar acute corneal pathology. However, by day 30 postinfection, wild-type mice had drastically more blood and lymphatic vessel projections into the cornea compared with gBT-I.1 mice, in which only lymphatic vessel growth in response to VEGF-C could be appreciated. Taken together, these results show that CD8(+) T cells are required to eliminate virus more efficiently from the cornea but play a minimal role in immunopathology as a source of VEGF-C.

Cluster analysis of host cytokine responses to biodefense pathogens in a whole blood ex vivo exposure model (WEEM)

Background

Rapid detection and therapeutic intervention for infectious and emerging diseases is a major scientific goal in biodefense and public health. Toward this end, cytokine profiles in human blood were investigated using a human whole blood ex vivo exposure model, called WEEM.

Results

Samples of whole blood from healthy volunteers were incubated with seven pathogens including Yersinia pseudotuberculosis, Yersinia enterocolitica, Bacillus anthracis, and multiple strains of Yersinia pestis, and multiplexed protein expression profiling was conducted on supernatants of these cultures with an antibody array to detect 30 cytokines simultaneously. Levels of 8 cytokines, IL-1α, IL-1β, IL-6, IL-8, IL-10, IP-10, MCP-1 and TNFα, were significantly up-regulated in plasma after bacterial exposures of 4 hours. Statistical clustering was applied to group the pathogens based on the host response protein expression profiles. The nearest phylogenetic neighbors clustered more closely than the more distant pathogens, and all seven pathogens were clearly differentiated from the unexposed control. In addition, the Y. pestis and Yersinia near neighbors were differentiated from the B. anthracis strains.

Conclusions

Cluster analysis, based on host response cytokine profiles, indicates that distinct patterns of immunomodulatory proteins are induced by the different pathogen exposures and these patterns may enable further development into biomarkers for diagnosing pathogen exposure.

Recurrent herpetic stromal keratitis in mice: a model for studying human HSK

Herpes simplex virus 1 (HSV-1) infection of the cornea leads to a potentially blinding disease, termed herpetic stromal keratitis (HSK) that is characterized by lesions of an immunoinflammatory nature. In spite of the fact that HSK typically presents as a recurrent disease due to reactivation of virus which latently infects the trigeminal ganglia, most murine studies of HSK have employed a primary and not recurrent model of the disease. This report documents the several recurrent models of HSK that have been developed and how data generated from these models differs in some important aspects from data generated following primary infection of the cornea. Chief among these differences is the fact that recurrent HSK takes place in the context of an animal that has a preexisting anti-HSV immune response, while primary HSK occurs in an animal that is developing such a response. We will document both differences and similarities that derive from this fundamental difference in these models with an eye towards possible vaccines and therapies that demonstrate promise in treating HSK.

Prenatal stress causes alterations in the morphology of microglia and the inflammatory response of the hippocampus of adult female mice

BACKGROUND

Stress during fetal life increases the risk of affective and immune disorders later in life. The altered peripheral immune response caused by prenatal stress may impact on brain function by the modification of local inflammation. In this study we have explored whether prenatal stress results in alterations in the immune response in the hippocampus of female mice during adult life.

METHODS

Pregnant C57BL/6 mice were subjected three times/day during 45 minutes to restraint stress from gestational Day 12 to delivery. Control non-stressed pregnant mice remained undisturbed. At four months of age, non-stressed and prenatally stressed females were ovariectomized. Fifteen days after surgery, mice received an i.p. injection of vehicle or of 5 mg/kg of lipopolysaccharide (LPS). Mice were sacrificed 20 hours later by decapitation and the brains were removed. Levels of interleukin-1β (IL1β), interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), interferon γ-inducible protein 10 (IP10), and toll-like receptor 4 mRNA were assessed in the hippocampus by quantitative real-time polymerase chain reaction. Iba1 immunoreactivity was assessed by immunocytochemistry. Statistical significance was determined by one-way or two-way analysis of variance.

RESULTS

Prenatal stress, per se, increased IL1β mRNA levels in the hippocampus, increased the total number of Iba1-immunoreactive microglial cells and increased the proportion of microglial cells with large somas and retracted cellular processes. In addition, prenatally stressed and non-stressed animals showed different responses to peripheral inflammation induced by systemic administration of LPS. LPS induced a significant increase in mRNA levels of IL-6, TNF-α and IP10 in the hippocampus of prenatally stressed mice but not of non-stressed animals. In addition, after LPS treatment, prenatally stressed animals showed a higher proportion of Iba1-immunoreactive cells in the hippocampus with morphological characteristics of activated microglia compared to non-stressed animals. In contrast, LPS induced similar increases in expression of IL1β and toll-like receptor 4 in both prenatally stressed and non-stressed animals.

CONCLUSION

These findings indicate that prenatal stress induces long-lasting modifications in the inflammatory status of the hippocampus of female mice under basal conditions and alters the immune response of the hippocampus to peripheral inflammation.

CXCR2 signaling and host defense following coronavirus-induced encephalomyelitis

Inoculation of the neurotropic JHM strain of mouse hepatitis virus (JHMV) into the central nervous system (CNS) of susceptible strains of mice results in wide-spread replication within glial cells accompanied by infiltration of virus-specific T lymphocytes that control virus through cytokine secretion and cytolytic activity. Virus persists within white matter tracts of surviving mice resulting in demyelination that is amplified by inflammatory T cells and macrophages. In response to infection, numerous cytokines/chemokines are secreted by resident cells of the CNS and inflammatory leukocytes that participate in both host defense and disease. Among these are the ELR-positive chemokines that are able to signal through CXC chemokine receptors including CXCR2. Early following JHMV infection, ELR-positive chemokines contribute to host defense by attracting CXCR2-expressing cells including polymorphonuclear cells to the CNS that aid in host defense through increasing the permeability the blood-brain-barrier (BBB). During chronic disease, CXCR2 signaling on oligodendroglia protects these cells from apoptosis and restricts the severity of demyelination. This review covers aspects related to host defense and disease in response to JHMV infection and highlights the different roles of CXCR2 signaling in these processes.

Inflammatory effects of highly pathogenic H5N1 influenza virus infection in the CNS of mice

The A/VN/1203/04 strain of the H5N1 influenza virus is capable of infecting the CNS of mice and inducing a number of neurodegenerative pathologies. Here, we examined the effects of H5N1 on several pathological aspects affected in parkinsonism, including loss of the phenotype of dopaminergic neurons located in the substantia nigra pars compacta (SNpc), expression of monoamines and indolamines in brain, alterations in SNpc microglia number and morphology, and expression of cytokines, chemokines, and growth factors. We find that H5N1 induces a transient loss of the dopaminergic phenotype in SNpc and now report that this loss recovers by 90 d after infection. A similar pattern of loss and recovery was seen in monoamine levels of the basal ganglia. The inflammatory response in lung and different regions of the brain known to be targets of the H5N1 virus (brainstem, substantia nigra, striatum, and cortex) were examined at 3, 10, 21, 60, and 90 d after infection. In each of these brain regions, we found a significant increase in the number of activated microglia that lasted at least 90 d. We also quantified expression of IL-1α, IL-1β, IL-2, IL-6, IL-9, IL-10, IL-12(p70), IL-13, TNF-α, IFN-γ, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor, macrophage colony-stimulating factor, eotaxin, interferon-inducible protein 10, cytokine-induced neutrophil chemoattractant, monocyte chemotactic protein-1, macrophage inflammatory protein (MIP) 1α, MIP-1β, and VEGF, and found that the pattern and levels of expression are dependent on both brain region and time after infection. We conclude that H5N1 infection in mice induces a long-lasting inflammatory response in brain and may play a contributing factor in the development of pathologies in neurodegenerative disorders.

EBNA3B-deficient EBV promotes B cell lymphomagenesis in humanized mice and is found in human tumors

Epstein-Barr virus (EBV) persistently infects more than 90% of the human population and is etiologically linked to several B cell malignancies, including Burkitt lymphoma (BL), Hodgkin lymphoma (HL), and diffuse large B cell lymphoma (DLBCL). Despite its growth transforming properties, most immune-competent individuals control EBV infection throughout their lives. EBV encodes various oncogenes, and of the 6 latency-associated EBV-encoded nuclear antigens, only EBNA3B is completely dispensable for B cell transformation in vitro. Here, we report that infection with EBV lacking EBNA3B leads to aggressive, immune-evading monomorphic DLBCL-like tumors in NOD/SCID/γc-/- mice with reconstituted human immune system components. Infection with EBNA3B-knockout EBV (EBNA3BKO) induced expansion of EBV-specific T cells that failed to infiltrate the tumors. EBNA3BKO-infected B cells expanded more rapidly and secreted less T cell-chemoattractant CXCL10, reducing T cell recruitment in vitro and T cell-mediated killing in vivo. B cell lines from 2 EBV-positive human lymphomas encoding truncated EBNA3B exhibited gene expression profiles and phenotypic characteristics similar to those of tumor-derived lines from the humanized mice, including reduced CXCL10 secretion. Screening EBV-positive DLBCL, HL, and BL human samples identified additional EBNA3B mutations. Thus, EBNA3B is a virus-encoded tumor suppressor whose inactivation promotes immune evasion and virus-driven lymphomagenesis.

Transplantation of hypoxia preconditioned bone marrow mesenchymal stem cells enhances angiogenesis and neurogenesis after cerebral ischemia in rats

Hypoxic preconditioning of stem cells and neural progenitor cells has been tested for promoting cell survival after transplantation. The present investigation examined the hypothesis that hypoxic preconditioning of bone marrow mesenchymal stem cells (BMSCs) could not only enhance their survival but also reinforce regenerative properties of these cells. BMSCs from eGFP engineered rats or pre-labeled with BrdU were pre-treated with normoxia (20% O(2), N-BMSCs) or sub-lethal hypoxia (0.5% O(2). H-BMSCs). The hypoxia exposure up-regulated HIF-1α and trophic/growth factors in BMSCs, including brain-derived neurotrophic factor (BDNF), glial cell-derived neurotrophic factor (GDNF), vascular endothelial growth factor (VEGF) and its receptor FIK-1, erythropoietin (EPO) and its receptor EPOR, stromal derived factor-1 (SDF-1) and its CXC chemokine receptor 4 (CXCR4). Meanwhile, many pro-inflammatory cytokines/chemokines were down-regulated in H-BMSCs. N-BMSCs or H-BMSCs were intravenously injected into adult rats 24h after 90-min middle cerebral artery occlusion. Comparing to N-BMSCs, transplantation of H-BMSCs showed greater effect of suppressing microglia activity in the brain. Significantly more NeuN-positive and Glut1-positive cells were seen in the ischemic core and peri-infarct regions of the animals received H-BMSC transplantation than that received N-BMSCs. Some NeuN-positive and Glut-1-positive cells showed eGFP or BrdU immunoflourescent reactivity, suggesting differentiation from exogenous BMSCs into neuronal and vascular endothelial cells. In Rotarod test performed 15days after stroke, animals received H-BMSCs showed better locomotion recovery compared with stroke control and N-BMSC groups. We suggest that hypoxic preconditioning of transplanted cells is an effective means of promoting their regenerative capability and therapeutic potential for the treatment of ischemic stroke.

The role of BCL11B in regulating the proliferation of human naive T cells

The effect of the B-cell chronic lymphocytic leukemia/lymphoma 11B gene (BCL11B) on human T-cell regulation remains unclear. To characterize the functions of BCL11B, recombinant BCL11B and BCL11B siRNA were transfected into human naive T cells to overexpress or knock down BCL11B expression, respectively. After BCL11B overexpression, the proliferation ability and the T-helper (Th) subset were increased, whereas no significant alteration in the expression pattern and clonality of the T-cell receptor Vβ subfamilies was observed. After BCL11B knockdown, a similar distribution of Vβ subfamilies was detected in the naive T cells; however, the proliferation capacity substantially decreased. Global gene expression profiling revealed that the dysregulated genes were mainly involved in T-cell activation and proliferation. BCL11B could selectively promote Th-cell differentiation because of increased CXCL10 and CXCL11 expression. BCL11B suppression may inhibit proliferation and induce apoptosis, which may relate to changes in the expression of CFLAR-CASP8-CASP10 in the mitochondrial pathways. In conclusion, BCL11B is required for T-cell survival; its overexpression could effectively increase the T-cell activation and proliferation abilities and Th-cell differentiation as well.

Antigen presentation by endothelial cells: what role in the pathophysiology of malaria?

Disruption of the endothelial cell (EC) barrier leads to pathology via edema and inflammation. During infections, pathogens are known to invade the EC barrier and modulate vascular permeability. However, ECs are semi-professional antigen-presenting cells, triggering T-cell costimulation and specific immune-cell activation. This in turn leads to the release of inflammatory mediators and the destruction of infected cells by effectors such as CD8(+) T-cells. During malaria, transfer of parasite antigens to the EC surface is now established. At the same time, CD8 activation seems to play a major role in cerebral malaria. We summarize here some of the pathways leading to antigen presentation by ECs and address the involvement of these mechanisms in the pathophysiology of cerebral malaria.

CXCL10: a candidate biomarker in transplantation

Interferon (IFN) γ-induced protein 10 kDa (IP-10) or C-X-C motif chemokine 10 (CXCL10) is a small cytokine belonging to the CXC chemokine family. This family of signaling molecules is known to control several biological functions and to also play pivotal roles in disease initiation and progression. By binding to its specific cognate receptor CXCR3, CXCL10 critically regulates chemotaxis during several immune-inflammatory processes. In particular, this chemokine controls chemotaxis during the inflammatory response resulting from allograft rejection after transplantation. Interestingly, a strong association has been described between CXCL10 production, immune response and the fate of the graft following allotransplantation. Enhanced CXCL10 production has been observed in recipients of transplants of different organs. This enhanced production likely comes from either the graft or the immune cells and is correlated with an increase in the concentration of circulating CXCL10. Because CXCL10 can be easily measured in the serum and plasma from a patient, the detection and quantitation of circulating CXCL10 could be used to reveal a transplant recipient's immune status. The purpose of this review is to examine the critical role of CXCL10 in the pathogenesis of allograft rejection following organ transplantation. This important role highlights the potential utilization of CXCL10 not only as a therapeutic target but also as a biomarker to predict the severity of rejection, to monitor the inflammatory status of organ recipients and, hopefully, to fine-tune patient therapy in transplantation.

A TLR4 agonist synergizes with dendritic cell-directed lentiviral vectors for inducing antigen-specific immune responses

TLR4 agonists can be used as adjuvants to trigger innate immune responses of antigen-presenting cells (APCs) such as dendritic cells (DCs) to enhance vaccine-specific immunity. Adjuvant effects of TLR4 agonists are mediated by downstream signaling controlled by both MyD88 and TRIF adapter proteins. In this study, we investigated the adjuvanting capacity of glucopyranosyl lipid A (GLA), a chemically synthesized TLR4 agonist, to boost antigen-specific immunity elicited by DC-directed lentiviral vectors (DC-LV). We found that stimulation by this agonist in vitro can activate DCs in a TLR4-dependent manner. The agonist can significantly boost DC-LV-induced humoral and cellular immune responses, resulting in better antitumor reactions in response to tumor challenges. We observed that the adjuvant-mediated enhancement of cytotoxic CD8(+) T cell responses is CD4(+) T cell-dependent and determined that in vitro the agonist stimulation involves the participation of both MyD88 and TRIF pathways to activate DCs. In vivo immunization study however revealed that adjuvant effects depend more on the MyD88 signaling as TRIF(-/-) mice but not MyD88(-/-) mice were able to maintain the enhanced CD8(+) T cell responses upon DC-LV immunization. Thus, our study supports the use of this TLR4 agonist as a potent adjuvant candidate for boosting DC-LV immunization.

Inhibition of CXCL10 release by monomeric C3bi and C4b

Cellulose acetate (CA) beads are often used for leucocyte apheresis therapy against inflammatory bowel disease. In order to clarify the mechanism of the anti-inflammatory effects of CA, global analysis of the molecules generated in blood by the interaction with CA beads was performed in this study. An activated medium was collected from whole blood that had been preincubated with CA beads, and the effects of the CA-activated medium on leucocyte function were investigated. Fresh blood was stimulated with lipopolysaccharide (LPS) or interferon (IFN)-β in the presence of the activated medium, and levels of chemokines and cytokines, including CXCL10 (IFN-inducible protein-10), and phosphorylated STAT1 (signal transducer and activator of transcription 1), which is known to be essential for CXCL10 production in leucocytes, were measured. IFN-β- or LPS-induced CXCL10 production, expression of CXCL10 mRNA and phosphorylation of STAT1 were significantly reduced in the presence of the medium pretreated with CA beads compared with the control without the CA bead treatment. The factors inhibiting CXCL10 production were identified as the C3 and C4 fragments by mass spectrometry. The monomeric C3bi and C4b proteins were abundant in the medium pretreated with CA beads. Furthermore, purified C3bi and C4b were found to inhibit IFN-β-induced CXCL10 production and STAT1 phosphorylation. Thus, STAT1-mediated CXCL10 production induced by stimulation with LPS or IFN was potently inhibited by monomeric C3bi and C4b generated by the interaction of blood with CA beads. These mechanisms mediated by monomeric C3bi and C4b may be involved in the anti-inflammatory effects of CA.

Porcine colon explants in the study of innate immune response to Entamoeba histolytica

Human amebiasis is caused by the protozoan Entamoeba histolytica. This protozoan is responsible for muco-hemorrhagic diarrhoea and liver abscess in affected populations. E. histolytica can be asymptomatic commensally confined to the intestinal lumen or can result in invasion of the colonic mucosa leading to ulceration and/or liver abscesses. Recently, human colonic explants have been identified as valuable in the study of host-parasite interactions. Here we investigated the potential of porcine colonic explants as an alternative to human tissues which are far less available. Porcine colonic explants were cultured with two strains of E. histolytica, one virulent (HM1:IMSS) and one avirulent (Rahman). Results from histopathological and real-time PCR analysis showed that porcine explants cultured with virulent ameba trophozoites react similarly to their human counterparts with an invasion of the tissue by the trophozoites and the triggering of typical innate immune response against the parasite. On the contrary, explants cultured with avirulent ameba trophozoites were preserved. The study open the way to the use of porcine colonic explants in the study of the complex interactions between the parasite and the host.

Protumoral role of monocytes in human B-cell precursor acute lymphoblastic leukemia: involvement of the chemokine CXCL10

Myelomonocytic cells play a key role in the progression of many solid tumors. However, very little is known about their contribution to the progression of hematopoietic cancers. We investigated the role of monocytes in the progression of human B-cell precursor acute lymphoblastic leukemia (BCP-ALL). We demonstrated that coculturing human monocytes in vitro with CD19+ BCP-ALL blasts from patients “conditioned” them to an inflammatory phenotype characterized by significant up-regulation of the chemokine, CXCL10. This phenotype was also observable ex vivo in monocytes isolated from BCP-ALL patients, which show elevated CXCL10 production compared with monocytes from healthy donors. Functionally, the “conditioned” monocytes promoted migration and invasive capacity of BCP-ALL cells. Increased invasion was mediated by matrix metalloproteinase 9 expression and activity in the BCP-ALL cells induced by the monocyte-derived CXCL10. However, neither the “conditioned” monocytes nor the CXCL10 produced by these cells had any effect on the proliferation/viability of BCP-ALL cells and angiogenesis. Collectively, our results strongly suggest a protumoral role for human monocytes in BCP-ALL, orchestrated by CXCL10 and its effect on tumor cell migration and invasion. These observations highlight the importance of the CXCL10/CXCR3 chemokine circuit in BCP-ALL progression.

Chemokines as markers of local inflammation and angiogenesis in patients with chronic subdural hematoma: a prospective study

OBJECTIVE

The goal of this study was to investigate the chemokines CCL2, CXCL8, CXCL9 and CXCL10 as markers of the inflammatory responses in chronic subdural hematoma (CSDH).

METHODS

Samples of peripheral venous blood and CSDH fluid (obtained during surgery) in 76 adult patients were prospectively analyzed. Chemokine values were assessed by a Multiplex antibody bead kit.

RESULTS

We found significantly higher levels of chemokines CCL2, CXCL8, CXCL9 and CXCL10 in hematoma fluid compared with serum.

CONCLUSIONS

Chemokines are elevated in the hematoma cavity of patients with CSDH. It is likely that these signaling modulators play an important role in promoting local inflammation. Furthermore, biological activity of CCL2 and CXCL8 may promote neovascularization within the outer CSDH membrane, and a compensatory angiostatic activity of CXCL9 and CXCL10 may contribute to repairing this disorder. This phenomenon was restricted to the hematoma site, and the systemic chemokine levels might not reflect local immune responses.

Long-term exposure of chemokine CXCL10 causes bronchiolitis-like inflammation

Chemokines and chemokine receptors have been implicated in the pathogenesis of bronchiolitis. CXCR3 ligands (CXCL10, CXCL9, and CXCL11) were elevated in patients with bronchiolitis obliterans syndrome (BOS) and chronic allorejection. Studies also suggested that blockage of CXCR3 or its ligands changed the outcome of T-cell recruitment and airway obliteration. We wanted to determine the role of the chemokine CXCL10 in the pathogenesis of bronchiolitis and BOS. In this study, we found that CXCL10 mRNA levels were significantly increased in patients with BOS. We generated transgenic mice expressing a mouse CXCL10 cDNA under control of the rat CC10 promoter. Six-month-old CC10-CXCL10 transgenic mice developed bronchiolitis characterized by airway epithelial hyperplasia and developed peribronchiolar and perivascular lymphocyte infiltration. The airway hyperplasia and T-cell inflammation were dependent on the presence of CXCR3. Therefore, long-term exposure of the chemokine CXCL10 in the lung causes bronchiolitis-like inflammation in mice.

Validation of urinary CXCL10 as a marker of borderline, subclinical, and clinical tubulitis

BACKGROUND

Renal allograft injury secondary to subclinical and clinical tubulitis remains an important cause of allograft fibrosis and loss despite modern immunosuppression. The goal of this study was to validate the previously reported use of urinary CXCL10 (interferon-γ-induced protein of 10 kDa) as a noninvasive marker of tubulitis in an independent clinical cohort.

METHODS

Urine samples (n=102) from 91 patients with protocol or indication biopsies were assayed for urinary CXCL10 using ELISA. The groups analyzed were as follows: normal histology (n=22); interstitial fibrosis and tubular atrophy (IFTA) (n=20); IFTA and borderline tubulitis (n=13); borderline (n=13), subclinical (n=17); and clinical tubulitis (n=17) without IFTA.

RESULTS

The ratio of urinary CXCL10 to creatinine (CXCL10: Cr) was found to distinguish borderline, subclinical and clinical tubulitis from normal histology, and IFTA. The area under the curve receiver operating characteristic curve to distinguish normal versus borderline and subclinical tubulitis was 0.845 (OR 1.407, P=0.0184); normal versus borderline, subclinical and clinical tubulitis was 0.835 (OR 1.400, P=0.0127). CXCL10: Cr demonstrated a sensitivity of 73.3% and specificity of 72.7% for normal versus borderline and subclinical tubulitis at a cut-off of 1.97 ng CXCL10/mmol Cr.

CONCLUSION

This study validates urinary CXCL10 as a noninvasive, sensitive, and specific marker for tubulitis in an independent cohort. The straightforward urine processing is accessible to clinical laboratories. We propose that CXCL10 may be useful as a supplementary noninvasive screening test for tubulitis in renal transplant patients, with a level more than 1.97 ng CXCL10/mmol Cr being a threshold to consider biopsy.

Ribavirin enhances IFN-α signalling and MxA expression: a novel immune modulation mechanism during treatment of HCV

The nucleoside analogue Ribavirin significantly increases patient response to IFN-α treatment of HCV, by directly inhibiting viral replication. Recent studies indicate that Ribavirin also regulates immunity and we propose that Ribavirin enhances specific interferon sensitive gene (ISG) expression by amplifying the IFN-α-JAK/STAT pathway. We found that IFN-α-induced STAT1 and STAT3 phosphorylation was increased in hepatocytes co-treated with Ribavirin and IFN-α, compared to IFN-α alone. Ribavirin specifically enhanced IFN-α induced mRNA and protein of the anti-viral mediator MxA, which co-localised with HCV core protein. These novel findings indicate for the first time that Ribavirin, in addition to its viral incorporation, also enhances IFN-α-JAK/STAT signalling, leading to a novel MxA-mediated immuno-modulatory mechanism that may enhance IFN-α anti-viral activity against HCV.

CXCL10 enhances radiotherapy effects in HeLa cells through cell cycle redistribution

Radiotherapy is a crucial treatment for cervical cancer, the second most common type of cancer in women worldwide. In this study, we investigated the effects of CXC chemokine ligand 10 (CXCL10) gene therapy combined with radiotherapy on cervical cancer using HeLa cells. TUNEL assay revealed that the apoptotic rate in the combined treatment of CXCL10 gene therapy and radiotherapy was greatly increased compared with that of CXCL10 or radiotherapy alone. Flow cytometry showed that CXCL10 overexpression in HeLa cells resulted in a prolonged G1 phase and shortened S phase at 72 h post-transfection. Western blot analysis revealed that p27(Kip1) was up-regulated in CXCL10-treated HeLa cells; however, cyclin E was down-regulated. These results indicate that the combination of CXCL10 gene therapy and radiotherapy is an effective strategy for the growth suppression of HeLa cells, and that CXCL10 enhances the radiotherapy effects through cell cycle redistribution. Our data provide new insight into the treatment of cervical carcinoma, involving an effective combination of gene therapy and radiotherapy against tumors.

Catechols in caffeic acid phenethyl ester are essential for inhibition of TNF-mediated IP-10 expression through NF-κB-dependent but HO-1- and p38-independent mechanisms in mouse intestinal epithelial cells

SCOPE

Caffeic acid phenethyl ester (CAPE) is an active constituent of honeybee propolis inhibiting nuclear factor (NF)-κB. The aims of our study were to provide new data on the functional relevance and mechanisms underlying the role of CAPE in regulating inflammatory processes at the epithelial interface in the gut and to determine the structure/activity relationship of CAPE.

METHODS AND RESULTS

CAPE significantly inhibited TNF-induced IP-10 expression in intestinal epithelial cells. Using various analogues, we demonstrated that substitution of catechol hydroxyl groups and addition of one extra hydroxyl group on ring B reversed the functional activity of CAPE to inhibit IP-10 production. The anti-inflammatory potential of CAPE was confirmed in ileal tissue explants and embryonic fibroblasts derived from TNF(ΔARE/+) mice. Interestingly, CAPE inhibited both TNF- and LPS-induced IP-10 production in a dose-dependent manner, independently of p38 MAPK, HO-1 and Nrf2 signaling pathways. We found that CAPE did not inhibit TNF-induced IκB phosphorylation/degradation or nuclear translocation of RelA/p65, but targeted downstream signaling events at the level of transcription factor recruitment to the gene promoter.

CONCLUSION

This study reveals the structure-activity effects and anti-inflammatory potential of CAPE in the intestinal epithelium.

Hepatitis D virus-specific cytokine responses in patients with chronic hepatitis delta before and during interferon alfa-treatment

BACKGROUND

Hepatitis delta is caused by infection with the hepatitis D virus (HDV) and is considered the most severe form of viral hepatitis. Treatment options for hepatitis delta are limited, with only 25% of patients responding to interferon (IFN)-alfa-based therapies. The role of the adaptive immune system in controlling HDV infection during spontaneous or treatment-induced viral clearance is not well understood.

METHODS

We studied HDV-specific cytokine production of peripheral blood mononuclear cells stimulated with HDV peptide pools as well as serum cytokine levels in well-characterized patients with chronic HDV infection before and during pegylated-interferon-alfa±adefovir therapy.

RESULTS

Hepatitis D virus-specific interleukin (IL)-2, IFN-γ-, interferon-inducible protein-10 and IL-10-responses were detectable in 53%, 35%, 65% and 6% of hepatitis delta patients. HDV-specific IFN-γ responses tended to be more common in patients with low HDV viral loads. HDV-specific cytokine responses declined during pegylated (PEG)-IFNa therapy and patterns of changes were associated with the treatment response. Serum cytokine levels also showed distinct changes during PEG-IFNa treatment.

CONCLUSION

We suggest that cellular HDV-specific immune responses contribute to the control of HDV infection and that cytokine responses may indicate response to type-I-IFN-based antiviral therapy of hepatitis delta.

Mast cells play a critical role in the systemic inflammatory response and end-organ injury resulting from trauma

BACKGROUND

Much of the morbidity after trauma results from excessive activation of the innate immune system. This is manifested as a systemic inflammatory response and associated end-organ damage. Although mast cells are known to be important in many immune responses, their role in the systemic response to severe trauma is unknown.

STUDY DESIGN

C57BL/6J-KitW-sh/BsmJ (mast cell deficient) and wild type mice were subjected to 1.5 hours of hemorrhagic shock plus bilateral femur fracture and soft tissue injury (HS/T), followed by resuscitation at 4.5 hours. Blood withdrawal volumes, mean arterial pressures, circulating cytokine, chemokine, high mobility group box-1 (HMGB-1), double strain DNA (dsDNA), transaminase levels, and histology in liver and lung were compared between groups.

RESULTS

Mast cell deficient mice exhibited greater hemodynamic stability than wild type mice. At baseline, the mast cell deficient mice exhibited no difference in any of the organ injury or inflammatory markers measured. As expected, wild type mice subjected to HS/T exhibited end-organ damage manifested by marked increases in circulating alanine transaminase, aspartate aminotransferase, and dsDNA levels, as well as histologic evidence of tissue necrosis. In clear contrast, mast cell deficient mice exhibited almost no tissue damage. Similarly, the magnitude of increased circulating cytokine and chemokine induced by HS/T was much less in the mast cell deficient mice than in the wild type group.

CONCLUSIONS

Mast cell deficiency resulted in a damped systemic inflammatory response, greatly attenuated multiple organ injury, and more stable hemodynamics in HS/T. So mast cells appear to be a critical component of the initial host response to severe injury.

Heparan sulfate binding by natural eastern equine encephalitis viruses promotes neurovirulence

The Alphavirus genus of the family Togaviridae contains mosquito-vectored viruses that primarily cause either arthritogenic disease or acute encephalitis. North American eastern equine encephalitis virus (NA-EEEV) is uniquely neurovirulent among encephalitic alphaviruses, causing mortality in a majority of symptomatic cases and neurological sequelae in many survivors. Unlike many alphaviruses, NA-EEEV infection of mice yields limited signs of febrile illness typically associated with lymphoid tissue replication. Rather, signs of brain infection, including seizures, are prominent. Use of heparan sulfate (HS) as an attachment receptor increases the neurovirulence of cell culture-adapted strains of Sindbis virus, an arthritogenic alphavirus. However, this receptor is not known to be used by naturally circulating alphaviruses. We demonstrate that wild-type NA-EEEV strain FL91-4679 uses HS as an attachment receptor and that the amino acid sequence of its E2 attachment protein is identical to those of natural isolates sequenced by RT-PCR amplification of field samples. This finding unequivocally confirms the use of HS receptors by naturally circulating NA-EEEV strains. Inactivation of the major HS binding domain in NA-EEEV E2 demonstrated that the HS binding increased brain replication and neurologic disease but reduced lymphoid tissue replication, febrile illness signs, and cytokine/chemokine induction in mice. We propose that HS binding by natural NA-EEEV strains alters tropism in vivo to antagonize/evade immune responses, and the extreme neurovirulence of wild-type NA-EEEV may be a consequence. Therefore, reinvestigation of HS binding by this and other arboviruses is warranted.

Claudin-1 expression in airway smooth muscle exacerbates airway remodeling in asthmatic subjects

BACKGROUND

Increased airway smooth muscle (ASM) mass is an essential component of airway remodeling and asthma development, and there is no medication specifically against it. Tight junction (TJ) proteins, which are expressed in endothelial and epithelial cells and affect tissue integrity, might exist in other types of cells and display additional functions in the asthmatic lung.

OBJECTIVE

The aim of this study was to investigate the existence, regulation, and function of TJ proteins in ASM in asthmatic patients.

METHODS

The expression and function of TJ proteins in primary ASM cell lines, human bronchial biopsy specimens, and a murine model of asthma were analyzed by means of RT-PCR, multispectral imaging flow cytometry, immunohistochemistry, Western blotting, 5-(and-6)-carboxyfluorescein diacetate succinimidyl ester staining, tritiated thymidine incorporation, wound-healing assay, and luminometric bead array.

RESULTS

Increased claudin-1 expression was observed in ASM of asthmatic patients, as well as in a murine model of asthma-like airway inflammation. Whereas IL-1β and TNF-α upregulated claudin-1 expression, it was downregulated by the T(H)2 cytokines IL-4 and IL-13 in primary human ASM cells. Claudin-1 was localized to the nucleus and cytoplasm but not to the cell surface in ASM cells. Claudin-1 played a central role in ASM cell proliferation, as demonstrated by increased ASM cell proliferation seen with overexpression and decreased proliferation seen with small interfering RNA knockdown of claudin-1. Overexpression of claudin-1 induced vascular endothelial growth factor and downregulated IL-6, IL-8, and IFN-γ-induced protein 10 production by ASM cells. Claudin-1 upregulation by IL-1β or TNF-α was suppressed by dexamethasone but not by rapamycin, FK506, or salbutamol.

CONCLUSION

These results demonstrate that claudin-1 might play a role in airway remodeling in asthmatic patients by means of regulation of ASM cell proliferation, angiogenesis, and inflammation.

Vesicular stomatitis virus expressing tumor suppressor p53 is a highly attenuated, potent oncolytic agent

Vesicular stomatitis virus (VSV), a negative-strand RNA rhabdovirus, preferentially replicates in and eradicates transformed versus nontransformed cells and is thus being considered for use as a potential anticancer treatment. The genetic malleability of VSV also affords an opportunity to develop more potent agents that exhibit increased therapeutic activity. The tumor suppressor p53 has been shown to exert potent antitumor properties, which may in part involve stimulating host innate immune responses to malignancies. To evaluate whether VSV expressing p53 exhibited enhanced oncolytic action, the murine p53 (mp53) gene was incorporated into recombinant VSVs with or without a functional viral M gene-encoded protein that could either block (VSV-mp53) or enable [VSV-M(mut)-mp53] host mRNA export following infection of susceptible cells. Our results indicated that VSV-mp53 and VSV-M(mut)-mp53 expressed high levels of functional p53 and retained the ability to lyse transformed versus normal cells. In addition, we observed that VSV-ΔM-mp53 was extremely attenuated in vivo due to p53 activating innate immune genes, such as type I interferon (IFN). Significantly, immunocompetent animals with metastatic mammary adenocarcinoma exhibited increased survival following treatment with a single inoculation of VSV-ΔM-mp53, the mechanisms of which involved enhanced CD49b+ NK and tumor-specific CD8+ T cell responses. Our data indicate that VSV incorporating p53 could provide a safe, effective strategy for the design of VSV oncolytic therapeutics and VSV-based vaccines.

Live attenuated influenza vaccine (LAIV) impacts innate and adaptive immune responses

Influenza A infection induces a massive inflammatory response in the lungs that leads to significant illness and increases the susceptibility to secondary bacterial pneumonia. The most efficient way to prevent influenza infection is through vaccination. While inactivated vaccines induce protective levels of serum antibodies to influenza hemaglutinin (HA) and neuraminidase (NA) surface proteins, these are strain specific and offer little protection against heterosubtypic influenza viruses. In contrast, live attenuated influenza vaccines (LAIVs) induce a T cell response in addition to antibody responses against HA and NA surface proteins. Importantly, LAIV vaccination induces a response in a mouse model that protects against illness due to heterosubtypic influenza strains. While it is not completely clear what is the mechanism of action of LAIV heterosubtypic protection in humans, it has been shown that LAIV induces heterosubtypic protection in mice that is dependent upon a Type 1 immune response and requires CD8 T cells. In this study, we show that LAIV-induced immunity leads to significantly reduced viral titers and inflammatory responses in the lungs of mice following heterosubtypic infection. Not only are viral titers reduced in LAIV vaccinated mice, the amounts of inflammatory cytokines and chemokines in lung tissue are significantly lower. Additionally, we show that LAIV vaccination of healthy adults also induces a robust Type 1 memory response including the production of chemokines and cytokines involved in T cell activation and recruitment. Thus, our results indicate that LAIV vaccination functions by inducing immune memory which can act to modulate the immune response to subsequent heterosubtypic challenge by influencing both innate and adaptive responses.

Chemokine receptor CXCR3 facilitates CD8(+) T cell differentiation into short-lived effector cells leading to memory degeneration

Strength of inflammatory stimuli during the early expansion phase plays a crucial role in the effector versus memory cell fate decision of CD8(+) T cells. But it is not known how early lymphocyte distribution after infection has an impact on this process. We demonstrate that the chemokine receptor CXCR3 is involved in promoting CD8(+) T cell commitment to an effector fate rather than a memory fate by regulating T cell recruitment to an antigen/inflammation site. After systemic viral or bacterial infection, the contraction of CXCR3(-/-) antigen-specific CD8(+) T cells is significantly attenuated, resulting in massive accumulation of fully functional memory CD8(+) T cells. Early after infection, CXCR3(-/-) antigen-specific CD8(+) T cells fail to cluster at the marginal zone in the spleen where inflammatory cytokines such as IL-12 and IFN-α are abundant, thus receiving relatively weak inflammatory stimuli. Consequently, CXCR3(-/-) CD8(+) T cells exhibit transient expression of CD25 and preferentially differentiate into memory precursor effector cells as compared with wild-type CD8(+) T cells. This series of events has important implications for development of vaccination strategies to generate increased numbers of antigen-specific memory CD8(+) T cells via inhibition of CXCR3-mediated T cell migration to inflamed microenvironments.

Sex differences in the inflammatory response of primary astrocytes to lipopolysaccharide

Background

Numerous neurological and psychiatric disorders show sex differences in incidence, age of onset, symptomatology or outcome. Astrocytes, one of the glial cell types of the brain, show sex differences in number, differentiation and function. Since astrocytes are involved in the response of neural tissue to injury and inflammation, these cells may participate in the generation of sex differences in the response of the brain to pathological insults. To explore this hypothesis, we have examined whether male and female astrocytes show a different response to an inflammatory challenge and whether perinatal testosterone influences this response.

Methods

Cortical astrocyte cultures were prepared from postnatal day 1 (one day after birth) male or female CD1 mice pups. In addition, cortical astrocyte cultures were also prepared from female pups that were injected at birth with 100 μg of testosterone propionate or vehicle. Cultures were treated for 5 hours with medium containing lipopolysaccharide (LPS) or with control medium. The mRNA levels of IL6, interferon-inducible protein 10 (IP10), TNFα, IL1β, Toll-like receptor 4 (TLR4), steroidogenic acute regulatory protein and translocator protein were assessed by quantitative real-time polymerase chain reaction. Statistical significance was assessed by unpaired t-test or by one-way analysis of variance followed by the Tukey post hoc test.

Results

The mRNA levels of IL6, TNFα and IL1β after LPS treatment were significantly higher in astrocytes derived from male or androgenized females compared to astrocytes derived from control or vehicle-injected females. In contrast, IP10 mRNA levels after LPS treatment were higher in astrocytes derived from control or vehicle-injected females than in those obtained from males or androgenized females. The different response of male and female astrocytes to LPS was due neither to differences in the basal expression of the inflammatory molecules nor to differences in the expression of the LPS receptor TLR4. In contrast, the different inflammatory response was associated with increased mRNA levels of translocator protein, a key steroidogenic regulator, in female astrocytes that were treated with LPS.

Conclusions

Male and female cortical astrocytes respond differentially to an inflammatory challenge and this may be predetermined by perinatal testosterone exposure.

A protective role of complement component 3 in T cell-mediated skin inflammation

Keratinocytes synthesize complement component 3 (C3) constitutively, and increased expression of C3 has been described during skin inflammation. In this study, we investigated the role of C3 in T cell-mediated allergic contact dermatitis, which is a clinical manifestation of contact sensitivity (CS). C3-deficient mice (C3KO) showed substantial higher CS responses to haptens, inducing a Th1 cytokine-mediated skin inflammation (2,4-dinitrofluorobenzene and dinitrochlorobenzene), and to haptens known to induce a Th2-polarized inflammatory response (fluoro-isothiocynate and toluene-2,4-diisocyanate) as compared to their wild-type (WT) controls. There was a higher influx of GR-1(+) , CD4(+) , and CD8(+) cells into the skin of hapten-treated C3KO mice compared with WT mice. Activated splenocytes from C3KO mice immunized with DNCB secreted higher amounts of IFN-γ compared with WT controls but not of Th2 (IL-4, IL-5, and IL-10) cytokines or IL-17. A higher secretion of IL-12 from splenocytes of C3KO mice as compared with WT mice was observed after TLR-4 ligand (LPS) or TLR-2 ligand (peptidoglycan) stimulation. Thus, an increased expression of IL-12 and of IFN-γ may be responsible for the increased hapten-induced inflammation in C3 deficiency. Finally, we demonstrated that C3KO mice developed oral tolerance to haptens to a lower degree than WT mice. Our findings provide a new insight into a novel anti-inflammatory role of C3 in skin inflammation.

Systemic DNA damage related to cancer

The importance of bystander effects is becoming more appreciated, as studies show they may affect the course of cancer and other chronic diseases. The term "bystander effects" refers to changes in naïve cells sharing the same milieu with cells that have been damaged. Bystander cells may be in contact with, or distant from, damaged cells. In addition, it has been shown in culture that not only physically damaged cells, but also cells that have become abnormal (i.e., cancerous or senescent) may induce bystander effects. Recently, we have shown a similar effect in animals. Mice harboring subcutaneous tumors exhibited elevated levels of DNA damage in distant organs. In contrast to cell culture, immune cells seemed to be involved in tumor-induced bystander effects in animals because CCL2-null tumor-bearing mice did not exhibit increased distant DNA damage. Here, we discuss some of the implications of these observations.

Cytokine profiling of pancreatic fluid using the ePFT collection method in tandem with a multiplexed microarray assay

Cytokines are secreted immunomodulating proteins involved in pancreatic stellate cell activation and propagation of fibrosis in chronic pancreatitis. We aim to show that cytokines can be identified from pancreatic fluid by (1) collecting pancreatic fluid with the ePFT method, (2) processing the fluid for cytokine-targeted microarray analysis, and (3) comparing cytokine profiles in pancreatic fluid of chronic pancreatitis (CP) patients and of chronic abdominal pain (CAP) controls. We endoscopically collected pancreatic fluid from patients with CP and those with CAP using the ePFT method. This fluid was subjected directly to a multiplexed cytokine protein microarray assay. Six patients (3 CP, 3 CAP) underwent a secretin-stimulated ePFT. The mean peak bicarbonate concentrations [meq/L] of the CP and CAP patients were 43 and 97, respectively. Statistically significant decreases in the cytokine concentrations of EGF, IP-10, eotaxin, IL-3, MIP-1a, IL-15, PDGF-AB/BB, and IL-1a were observed in the CP specimens (p<0.05). We have successfully identified differences in the abundance of cytokines in ePFT-collected pancreatic fluid with a multiplexed microarray assay comparing CP and CAP controls. Further targeted investigation of cytokines in ePFT-collected fluid will broaden our knowledge of pancreatic immune response and pathogenesis in chronic pancreatitis.

Transcriptomic analysis of milk somatic cells in mastitis resistant and susceptible sheep upon challenge with Staphylococcus epidermidis and Staphylococcus aureus

Background

The existence of a genetic basis for host responses to bacterial intramammary infections has been widely documented, but the underlying mechanisms and the genes are still largely unknown. Previously, two divergent lines of sheep selected for high/low milk somatic cell scores have been shown to be respectively susceptible and resistant to intramammary infections by Staphylococcus spp. Transcriptional profiling with an 15K ovine-specific microarray of the milk somatic cells of susceptible and resistant sheep infected successively by S. epidermidis and S. aureus was performed in order to enhance our understanding of the molecular and cellular events associated with mastitis resistance.

Results

The bacteriological titre was lower in the resistant than in the susceptible animals in the 48 hours following inoculation, although milk somatic cell concentration was similar. Gene expression was analysed in milk somatic cells, mainly represented by neutrophils, collected 12 hours post-challenge. A high number of differentially expressed genes between the two challenges indicated that more T cells are recruited upon inoculation by S. aureus than S. epidermidis. A total of 52 genes were significantly differentially expressed between the resistant and susceptible animals. Further Gene Ontology analysis indicated that differentially expressed genes were associated with immune and inflammatory responses, leukocyte adhesion, cell migration, and signal transduction. Close biological relationships could be established between most genes using gene network analysis. Furthermore, gene expression suggests that the cell turn-over, as a consequence of apoptosis/granulopoiesis, may be enhanced in the resistant line when compared to the susceptible line.

Conclusions

Gene profiling in resistant and susceptible lines has provided good candidates for mapping the biological pathways and genes underlying genetically determined resistance and susceptibility towards Staphylococcus infections, and opens new fields for further investigation.

Indications of Th1 and Th17 responses in cerebrospinal fluid from patients with Lyme neuroborreliosis: a large retrospective study

Background

Previous studies indicate that successful resolution of Lyme neuroborreliosis (NB) is associated with a strong T helper (Th) 1-type cytokine response in the cerebrospinal fluid (CSF) followed by a down-regulating Th2 response, whereas the role of the recently discovered Th17 cytokine response is unknown.

Methods

To investigate the relative contribution of different Th associated cytokine/chemokine responses, we used a multiple bead array to measure the levels of CXCL10 (Th1 marker), CCL22 (Th2 marker), IL-17 (Th17 marker) and CXCL8 (general inflammation marker), in serum and in CSF from untreated patients with confirmed NB (n = 133), and non-NB patients (n = 96), and related the findings to clinical data. Samples from patients with possible early NB (n = 15) and possible late NB (n = 19) were also analysed, as well as samples from an additional control group with orthopaedic patients (n = 17), where CSF was obtained at spinal anaesthesia.

Results

The most prominent differences across groups were found in the CSF. IL-17 was elevated in CSF in 49% of the patients with confirmed NB, but was not detectable in the other groups. Patients with confirmed NB and possible early NB had significantly higher CSF levels of CXCL10, CCL22 and CXCL8 compared to both the non-NB group and the control group (p < 0.0001 for all comparisons). Patients in the early NB group, showing a short duration of symptoms, had lower CCL22 levels in CSF than did the confirmed NB group (p < 0.0001). Furthermore, patients within the confirmed NB group showing a duration of symptoms <2 weeks, tended to have lower CCL22 levels in CSF than did those with longer symptom duration (p = 0.023). Cytokine/chemokine levels were not correlated with clinical parameters or to levels of anti-Borrelia-antibodies.

Conclusion

Our results support the notion that early NB is dominated by a Th1-type response, eventually accompanied by a Th2 response. Interestingly, IL-17 was increased exclusively in CSF from patients with confirmed NB, suggesting a hitherto unknown role for Th17 in NB. However, for conclusive evidence, future prospective studies are needed.

CXCL10 expressing hematopoietic-derived cells are requisite in defense against HSV-1 infection in the nervous system of CXCL10 deficient mice

The chemokine CXCL10 is crucial for the control of viral replication through the regulation of mobilization of antigen-specific T cells to sites of infection. CXCL10 is highly expressed both at sites of inflammation as well as constitutively within lymphoid organs by both bone marrow (BM)-derived and non-BM-derived cells. However, the relative immunologic importance of CXCL10 expressed by these divergent sources relative to HSV-1 infection is unknown. Using mouse chimeras reconstituted with either wild type or CXCL10 deficient mouse BM, we show BM-derived, radiation-sensitive cells from wild type mice were solely responsible for resistance to HSV-1 in the trigeminal ganglia and brain stem. The resistance was not reflected by a deficiency in the recruitment of effector cells to sites of inflammation or expression of chemokines or IFN-gamma and likely results from additional, yet-to-be-determined factors emanating from wild type, BM-derived cells.

Plasma IP-10 as a predictor of serious bacterial infection in infants less than 4 months of age

BACKGROUND

Early diagnosis of serious bacterial infection (SBI) in young infants is a difficult problem by clinical symptoms and signs. The goal of this study is to evaluate the predictive value of plasma IP-10 levels for early diagnosis of SBI in young infants <4 months of age.

METHODS

We enrolled pediatric patients who were <4 months of age with a clinical suspicion to have SBI admitted in neonatal intensive care unit or complete nursing unit of Pediatric Department of Kaohsiung Medical University Hospital. Blood was drawn for measurement of complete blood counts, C-reactive protein (CRP) and plasma IP-10 levels and microbiological cultures were obtained at the time of admission.

RESULTS

There were 60 patients enrolled in this study. The SBI group (n = 21) have higher plasma IP-10 levels than those infants without SBI (n = 39) [median 104.8 (range 0-1457.1) versus 0 (range 0-129.3) pg ml(-1), P = 0.0161 after adjusting age]. A plasma IP-10 level >48.2 pg ml(-1) had the best diagnostic accuracy for indicating SBI {sensitivity 81.0% [95% confidence interval (CI) 71.1-90.1%]; specificity 94.9% [95% CI 65.4-87.0%]; positive likelihood ratio 15.9, negative likelihood ratio 0.2}.

CONCLUSION

In infants who were <4 months of age with suspicion of SBI, IP-10 assay might be a good predictor. Key words: chemokine, IP-10, serious bacterial infection, young infant, C-reactive protein.