IL-6 Expression In Cells Research Articles

Isotretinoin-Delonix polymeric nanoparticles: Potentials for skin follicular targeting in acne treatment

In acne management, oral isotretinoin (IST) is associated with various untoward systemic effects, while its topical formulation has irritation side effects. Delonix (DLX) is a natural galactomannan derived from Delonix regia seed that can fabricate nanoparticles for topical skin delivery. This study aims to develop IST-DLX nanoparticles and assess their prospects for acne treatment. Fluorescent-DLX nanoparticles (made with a lipophilic BODIPY dye) or IST-DLX nanoparticles were prepared and characterized. BODIPY-DLX nanoparticles’ skin distribution and IST-DLX nanoparticles’ in-vitro targeting were assessed in pig ear skin, inflammatory modulation was assessed in AMJ-2 macrophage cells, while skin penetration and irritation were assessed in Wistar rats. IST-DLX nanoparticles had ≈230 nm, negative zeta potential, and ≈30% encapsulation efficiency. Confocal showed BODIPY in DLX nanoparticles accumulated in hair follicles as compared to BODIPY solution. IST-DLX nanoparticles released ≈37% IST over 48 h and increased IST 3-fold in hair follicles compared to IST solution. IST-DLX nanoparticles suppressed IL-6 expression in cells and reduced photo-irritation in Wistar rats compared to IST solution. In conclusion, IST-DLX nanoparticles may target and deliver adequate IST to skin layers associated with acne, avoid systemic penetration, modulate inflammatory pathogenic acne stage and prevent IST topical photo-irritation.

Malat1 Suppresses Immunity to Infection through Promoting Expression of Maf and IL-10 in Th Cells.

Despite extensive mapping of long noncoding RNAs in immune cells, their function in vivo remains poorly understood. In this study, we identify over 100 long noncoding RNAs that are differentially expressed within 24 h of Th1 cell activation. Among those, we show that suppression of Malat1 is a hallmark of CD4+ T cell activation, but its complete deletion results in more potent immune responses to infection. This is because Malat1-/- Th1 and Th2 cells express lower levels of the immunosuppressive cytokine IL-10. In vivo, the reduced CD4+ T cell IL-10 expression in Malat1-/- mice underpins enhanced immunity and pathogen clearance in experimental visceral leishmaniasis (Leishmania donovani) but more severe disease in a model of malaria (Plasmodium chabaudi chabaudi AS). Mechanistically, Malat1 regulates IL-10 through enhancing expression of Maf, a key transcriptional regulator of IL-10 Maf expression correlates with Malat1 in single Ag-specific Th cells from P. chabaudi chabaudi AS-infected mice and is downregulated in Malat1-/- Th1 and Th2 cells. The Malat1 RNA is responsible for these effects, as antisense oligonucleotide-mediated inhibition of Malat1 also suppresses Maf and IL-10 levels. Our results reveal that through promoting expression of the Maf/IL-10 axis in effector Th cells, Malat1 is a nonredundant regulator of mammalian immunity.

An Ayurvedic herbal extract inhibits oral epithelial cell IL-8 responses to host and bacterial agonists

BackgroundNatural products constitute a promising class of therapeutics for the treatment of gingivitis and periodontitis as well as the maintenance of oral health. However, the limited understanding behind their potential mechanisms and modes of action have hampered their incorporation into popular western therapeutics. This in vitro study characterizes an Ayurvedic herbal extract mixture, which has been clinically shown to promote gingival health and homeostasis.MethodsTelomerase immortalized gingival keratinocytes (TIGK) were infected with either Fusobacterium nucleatum cell wall, live F. nucleatum, IL-1β or TNF-α for 4 hours with and without the herbal extract. The immunomodulatory effects of the extract on host IL-8 production was measured by ELISA.ResultsIt was found that the Ayurvedic herbal extract mixture inhibited gingival epithelial cell IL-8 expression in response to both bacterial and host cytokine agonists. The herbal extract inhibited IL-8 stimulated by F. nucleatum cell wall, live F. nucleatum, IL-1β, and TNF-α in a dose-dependent manner that was not a result of host cell death. Furthermore, the extract showed significantly different ID50 doses demonstrating the differential ability to modulate both stimulated and basal IL-8 levels.ConclusionsIn vitro investigation of this herbal extract mixture revealed that it has the ability to modulate gingival epithelial cell IL-8 expression in response to stimulation by bacterial components and host pro-inflammatory signals. This data demonstrates that the reduction in the gingival epithelial cell IL-8 response may in part be responsible for the previously reported ability of the Ayurvedic herbal extract mixture to reduce gingivitis in two separate human clinical studies.

Intermediate Monocytes in Acute Alcoholic Hepatitis Are Functionally Activated and Induce IL-17 Expression in CD4+ T Cells.

In humans, the three main circulating monocyte subsets are defined by their relative cell surface expression of CD14 and CD16. They are all challenging to study because their characteristics are strongly context specific, and this has led to a range of conflicting reports about their function, which is especially so for CD14++CD16+ (intermediate) monocytes. Ex vivo cultures are also often confounded by the concomitant use of immunosuppressive drugs. We therefore sought to characterize the phenotype and function of intermediate monocytes in the setting of acute inflammation prior to treatment in a cohort of 41 patients with acute alcoholic hepatitis (AH). Circulating intermediate monocytes were enriched in patients with AH and had an activated phenotype with enhanced expression of CCR2 and CD206 compared with healthy controls. Proinflammatory cytokine expression, including IL-1β and IL-23, was also higher than in healthy controls, but both classical (CD14++CD16-) and intermediate monocytes in AH were refractory to TLR stimulation. Compared with healthy controls, both AH monocyte subsets had greater phagocytic capacity, enhanced ability to drive memory T cell proliferation in coculture, and skewed CD4+ T cells to express an increased ratio of IL-17/IFN-γ. Furthermore, liver tissue from AH patients demonstrated an enrichment of monocytes including the intermediate subset compared with controls. These data demonstrate that intermediate monocytes are expanded, functionally activated, induce CD4+ T cell IL-17 expression, and are enriched in the liver of patients with AH.

LncRNA CASC2 is up-regulated in osteoarthritis and participates in the regulation of IL-17 expression and chondrocyte proliferation and apoptosis

Long non-coding RNAs (lncRNA) CASC2 is a key player in cancer biology. Our new findings showed that both lncRNA CASC2 and IL-17 were up-regulated in plasma of osteoarthritis patients. Plasma levels of lncRNA CASC2 and IL-17 were significantly and positive correlated only in osteoarthritis patients. Overexpression of lncRNA CASC2 led to up-regulated expression of IL-17 in cells of human chondrocyte cell line CHON-001 (ATCC® CRL-2846™). In addition, overexpression of lncRNA CASC2 inhibited the proliferation, and promoted the apoptosis of chondrocyte. Therefore, lncRNA CASC2 is up-regulated in osteoarthritis and participates in the regulation of IL-17 expression and chondrocyte proliferation and apoptosis.

Activation of Human CD11b+ B1 B-Cells by Trypanosoma cruzi-Derived Proteins Is Associated With Protective Immune Response in Human Chagas Disease.

B-cells mediate humoral adaptive immune response via the production of antibodies and cytokines, and by inducing T-cell activation. These functions can be attributed to distinct B-cell subpopulations. Infection with Trypanosoma cruzi, the causative agent of Chagas disease, induces a polyclonal B-cell activation and lytic antibody production, critical for controlling parasitemia. Individuals within the chronic phase of Chagas disease may remain in an asymptomatic form (indeterminate), or develop severe cardiomyopathy (cardiac form) that can lead to death. Currently, there is no effective vaccine to prevent Chagas disease, and no treatment to halt the development of the cardiomyopathy once it is installed. The pathology associated with cardiac Chagas disease is a result of an inflammatory reaction. Thus, discovering characteristics of the host's immune response that favor the maintenance of favorable heart function may unveil important immunotherapeutic targets. Given the importance of B cells in antibody production and parasite control, we investigated T. cruzi-derived antigenic fractions responsible for B-cell activation and whether frequencies and functional characteristics of B-cell subpopulations are associated with different clinical outcomes of human Chagas disease. We stimulated cells from indeterminate (I) and cardiac (C) Chagas patients, as well as non-infected individuals (NI), with T. cruzi-derived protein- (PRO), glycolipid- (GCL) and lipid (LIP)-enriched fractions and determined functional characteristics of B-cell subpopulations. Our results showed that the frequency of B-cells was similar amongst groups. PRO, but not GCL nor LIP, led to an increased frequency of B1 B-cells in I, but not C nor NI. Although stimulation with PRO induced higher TNF expression by B1 B-cells from C and I, as compared to NI, it induced expression of IL-10 in cells from I, but not C. Stimulation with PRO induced an increased frequency of the CD11b+ B1 B-cell subpopulation, which was associated with better cardiac function. Chagas patients displayed increased IgM production, and activation of gamma-delta T-cells, which have been associated with B1 B-cell function. Our data showed that PRO activates CD11b+ B1 B-cells, and that this activation is associated with a beneficial clinical status. These findings may have implications in designing new strategies focusing on B-cell activation to prevent Chagas disease cardiomyopathy.

MiR-21 silencing ameliorates experimental autoimmune encephalomyelitis by promoting the differentiation of IL-10-producing B cells.

IL-10-producing regulatory B (IL-10+ Breg) cells promote tolerance in autoimmune diseases and transplantation. However, it remains unclear whether microRNAs are involved in the development of IL-10+ Breg cells. Here, we found that microRNA-21 (miR-21) acts as an upstream regulator of IL-10 by targeting the 3' untranslated region of IL-10 mRNA. We also demonstrated that IL-10+ Breg cells exhibit lower miR-21 expression than non-Breg cells and that miR-21 acts as a potent negative regulator of the differentiation of IL-10+ Breg cells. Accordingly, specific inhibition of miR-21 using antisense oligonucleotides markedly promoted B cell IL-10 expression. Thus, IL-10 is a direct target of miR-21. Moreover, silencing of miR-21 significantly alleviated the severity of experimental autoimmune encephalomyelitis (EAE), and this change was associated with an increase in the number of IL-10+ Breg cells. Finally, we demonstrated that miR-21-silenced B cells exert their suppressive activity through effector T cells in an IL-10-dependent manner.Thus, we characterized a B cell-intrinsic microRNA pathway that inhibits the differentiation of IL-10+ Breg cells and promotes autoimmunity. miR-21 silencing therefore represents a new therapeutic strategy for the treatment of autoimmune diseases.

Dimethyl Fumarate Treatment Mediates an Anti-Inflammatory Shift in B Cell Subsets of Patients with Multiple Sclerosis.

The therapeutic mode of action of dimethyl fumarate (DMF), approved for treating patients with relapsing-remitting multiple sclerosis, is not fully understood. Recently, we and others demonstrated that Ab-independent functions of distinct B cell subsets are important in mediating multiple sclerosis (MS) relapsing disease activity. Our objective was to test whether and how DMF influences both the phenotype and functional responses of disease-implicated B cell subsets in patients with MS. High-quality PBMC were obtained from relapsing-remitting MS patients prior to and serially after initiation of DMF treatment. Multiparametric flow cytometry was used to monitor the phenotype and functional response-profiles of distinct B cell subsets. Total B cell counts decreased following DMF treatment, largely reflecting losses of circulating mature/differentiated (but not of immature transitional) B cells. Within the mature B cell pool, DMF had a greater impact on memory than naive B cells. In keeping with these in vivo effects, DMF treatment in vitro remarkably diminished mature (but not transitional B cell) survival, mediated by inducing apoptotic cell death. Although DMF treatment (both in vivo and in vitro) minimally impacted B cell IL-10 expression, it strongly reduced B cell expression of GM-CSF, IL-6, and TNF-α, resulting in a significant anti-inflammatory shift of B cell response profiles. The DMF-mediated decrease in B cell proinflammatory cytokine responses was further associated with reduced phosphorylation of STAT5/6 and NF-κB in surviving B cells. Together, these data implicate novel mechanisms by which DMF may modulate MS disease activity through shifting the balance between pro- and anti-inflammatory B cell responses.

Functions of IL-4 and Control of Its Expression.

IL-4 has been called the "prototypic immunoregulatory cytokine." Like many cytokines, it can affect a variety of target cells in multiple ways. IL-4 has an important role in regulating antibody production, hematopoiesis and inflammation, and the development of effector T-cell responses. It is produced only by a subset of activated hematopoietic cells, including T cells and FcεRl+ mast cells and basophils. Based on the different tissue distribution and access to distinct target cells, IL-4 derived from T and FcεRl+ cells may have quite different effects on these immunological processes. In view of this, as well as the clear correlation of aberrant expression with disease, it is of interest to understand the signals that regulate IL-4 expression in a cell-specific manner. Recently, progress has been made in defining the T-cell- and FcεRl-receptor-mediated signals that stimulate IL-4 gene expression. These studies have demonstrated that there are common and cell-specific signaling pathways that regulate production of this cytokine. In this review, we summarize the activities of IL-4 defined both in vitro and in vivo and compare the signals leading to IL-4 expression in cells of both T- and mast-cell lineage.

CD14++CD16+ Monocytes Are Enriched by Glucocorticoid Treatment and Are Functionally Attenuated in Driving Effector T Cell Responses.

Human peripheral monocytes have been categorized into three subsets based on differential expression levels of CD14 and CD16. However, the factors that influence the distribution of monocyte subsets and the roles that each subset plays in autoimmunity are not well studied. In this study, we show that circulating monocytes from patients with autoimmune uveitis exhibit a skewed phenotype toward intermediate CD14(++)CD16(+) cells, and that this is associated with glucocorticoid therapy. We further demonstrate that CD14(++)CD16(+) monocytes from patients and healthy control donors share a similar cell-surface marker and gene expression profile. Comparison of the effects of intermediate CD14(++)CD16(+) monocytes with classical CD14(++)CD16(-) and nonclassical CD14(+)CD16(++) monocytes revealed that the intermediate CD14(++)CD16(+) subset had an attenuated capacity to promote both naive CD4(+) T cell proliferation and polarization into a Th1 phenotype, and memory CD4(+) T cell proliferation and IL-17 expression. Furthermore, CD14(++)CD16(+) cells inhibit CD4(+) T cell proliferation induced by other monocyte subsets and enhance CD4(+) T regulatory cell IL-10 expression. These data demonstrate the impact of glucocorticoids on monocyte phenotype in the context of autoimmune disease and the differential effects of monocyte subsets on effector T cell responses.

Platelet factor 4 limits Th17 differentiation and ischaemia-reperfusion injury after liver transplantation in mice.

Liver ischaemia/reperfusion injury (IRI) is a serious pathologic process encountered in a number of clinical syndromes including liver transplantation, liver resection, trauma and haemorrhagic shock. Platelet factor 4 (PF4) was the first discovered CXC chemokine and is found in platelet granules at very high concentration. In this study, we provide strong evidence that PF4 is involved directly in liver innate immune response against IRI by regulating Th17 differentiation. PF4 deficiency aggravates liver IRI, as shown by higher serum alanine aminotransferase (ALT) levels and Suzuki scores. PF4 deficiency promotes Th17 response with higher levels of IL-23, IL-6 and IL-17, which aggravates liver IRI. Furthermore, PF4 deficiency limits suppressor of cytokine signalling 3 (SOCS3) expressions, and PF4 fails to suppress expression of IL-17 in cells transfected with SOCS3 SiRNA. In conclusion, PF4 limits liver IRI through IL-17 inhibition via upregulation of SOCS3.

Proliferation conditions promote intrinsic changes in NK cells for an IL-10 response.

Constitutively found at high frequencies, the role for NK cell proliferation remains unclear. In this study, a shift in NK cell function from predominantly producing IFN-γ, a cytokine with proinflammatory and antimicrobial functions, to producing the immunoregulatory cytokine IL-10 was defined during extended murine CMV infection. The response occurred at times subsequent to IL-12 production, but the NK cells elicited acquired responsiveness to IL-12 and IL-21 for IL-10 production. Because neither IL-12 nor IL-21 was required in vivo, however, additional pathways appeared to be available to promote NK cell IL-10 expression. In vitro studies with IL-2 to support proliferation and in vivo adoptive transfers into murine CMV-infected mice demonstrated that NK cell proliferation and further division enhanced the change. In contrast to the sustained open profile of the IFN-γ gene, NK cells responding to infection acquired histone modifications in the IL-10 gene indicative of changing from a closed to an open state. The IL-10 response to IL-12 was proliferation dependent ex vivo if the NK cells had not yet expanded in vivo but independent if they had. Thus, a novel role for proliferation in supporting changing innate cell function is reported.

In Allogeneic Transplant Recipients Th17 Cells Originate From Donor Stem Cells and Reside In Target Organs of Chronic Graft-Versus-Host Disease

Graft-vs-host disease (GVHD) remains a major complication of allogeneic hematopoietic cell transplantation (HCT). Acute GVHD results from activated donor T cells that infiltrate and damage target organs, producing an inflammatory state. In contrast, the pathophysiology of chronic graft-vs-host disease (cGVHD) remains poorly understood. cGVHD can follow acute GVHD or emerge de novo (>d+100). The clinical picture varies and manifestations can resemble autoimmune disorders. Because IL-17 has emerged as a principal cytokine involved in autoimmunity, Th17 cells have attracted much attention in the transplant community. While IFNg-producing Th1 cells appear to drive acute GVHD, the role of Th17 cells in the pathophysiology of GVHD has not been fully clarified.Here, we used an established minor-antigen disparate mouse model of acute and chronic GVHD to examine the emergence of IL-17+CD4+ Th17 cells post-HCT. Lethally irradiated BALB.B mice received pure hematopoietic stem cells (HSC; cKIT+Thy1.1loSca1+Lin-) or HSC plus splenic T cells from C57BL/6 donors (HSC: GFP; TC: CD45.1+). At several time points lymphoid and GVHD target organs were analyzed for donor T cell infiltration and T cell IL-17 expression. In this model recipients of HSC + T cells developed acute GVHD with intestinal involvement (diarrhea, weight loss) and a mortality of ∼30%, while mice given pure HSC remained healthy. Survivors stabilized around d45, but developed clinically evident chronic GVHD after 6-12 mo manifested by sclerodermatous skin excoriations and liver fibrosis/cirrhosis. Donor T cell infiltration of tissues (spleen, lymph nodes (LN), liver, intestines) was high at 2 and 4 wks post-HCT, but there was no detectable IL-17 production by CD4 cells during acute GVHD. The degree of donor T cell infiltration decreased (as acute GVHD improved) in these tissues. However, at 2 mo post-HCT higher percentages CD4+IL-17+ cells were observed, first in intestines and mesenteric LN, followed by liver and skin. At all time points post-HCT proportions of Th17 cells were higher in HCT recipients (of HSC +/- T cells) as compared to normal wild-type (WT) tissues. To summarize, our key findings are: (i) In our model acute GVHD was driven by adoptively transferred mature (CD4+) T cells that acquired a Th1 phenotype, whereas IL-17 producing donor cells were not detectable during this period. IFNg and T-bet are negative regulators of RORgT, the master regulator of Th17. Thus, this observation is consistent with the idea that in the presence of donor Th1 cells the development of Th17 cells is suppressed. (ii) The effect of Th1-related suppression of Th17 persisted beyond the acute phase: recipients of T-cell replete grafts that survived acute GVHD but later developed chronic GVHD did not demonstrate increased CD4+IL-17+ cells. In these mice, organ-infiltrating donor T cells were primarily adoptively transferred T cells, supporting the postulation that no plasticity exists between committed Th1 and Th17 cells. (iii) Signs of chronic GVHD were observed in animals that had not suffered from severe acute GVHD. In particular, in groups without acute GVHD we observed CD4+IL-17+ cells starting at 2 mo, peaking around 6 mo and which stabilized >1 yr post-HCT. In spleen and peripheral LN of these mice only low levels of CD4+IL-17+ cells were detectable, but their proportion was high in GVHD target organs (liver, intestines, skin). The susceptibility of organs appeared to change post-HCT with high proportions of CD4+IL-17+ cells in the intestines at 2 mo post-HCT that decreased over time. In contrast, CD4+IL-17+ cells in the liver increased later in the time course (Figures). (iv) A centrally important observation was that CD4+IL-17+ cells primarily originated from donor HSC, even in recipients of mature donor T cells. Likewise, recipients of pure HSC showed increasing proportions of Th17 cells over time, and could also manifest signs of cGVHD.From our model we conclude that IL-17 does not contribute to acute inflammatory GVHD. However, IL-17 can be involved in an alternative pathophysiologic mode of chronic GVHD development in the absence of acute inflammation. Since CD4+IL-17+ cells derive from donor HSC and undergo maturation in the host this form of GVHD is delayed, and the emergence and activity of these cells appears to constitute a true autoimmune phenomenon. Our novel hypothesis may explain parts of the complex and obscure pathophysiology of chronic GVHD. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

S21 Type-2 Innate lymphoid cells induce CD4 T helper cell type-2 immune functions

IntroductionType-2 innate lymphoid cells (ILC2) are a novel subset of immune cells characterised by their responsiveness to interleukin (IL)-33 and their production of type-2 cytokines (including IL-5, IL-9, IL-13). ILC2...

A critical role of dendritic cells in CD8 T cell IL-10 expression during inflammatory response triggered by CD40-activated B cells (159.16)

Abstract CD40LBTg mice, expressing a CD40 ligand (CD40L) transgene on B cells, represent a model for human diseases where B cells aberrantly express CD40L or receive excess CD40/CD40L signaling under inflammatory conditions. Here, we show that B cells expressing transgenic CD40L are capable of priming CD8 T cells and generate strong antigen-specific cytotoxicity. Adoptively transferred SIINFEKL peptide-loaded B cells from CD40LBTg but not wild type mice were able to activate self-reactive OT-I CD8 T cells upon immunization with OVA plus alum and trigger diabetes in RIP-OVA mice by enhancing the help of endogenous self-reactive CD4 T cells. CD40L expressing B cells also trigger spontaneous activation of splenic CD8 T cells, which rapidly up-regulate PD-1, Blimp-1 and LAG-3 and lose cytotoxicity along with IL-10 expression via interaction with PDL-1hi CD11c+ dendritic cells in T cell zones. Thus, CD11c+ dendritic cells from CD40LBTg mice exhibit regulatory phenotype, which block granzyme B expression and preferentially induce IL-10 expression in activated CD8 T cells. These results demonstrate that constitutive CD40 signaling on B cells under inflammation increases the risk of breaking peripheral CD8 T cell tolerance. However, the presence of CD40-activated B cells results in PDL-1hi CD11c+ dendritic cells, which exhibit a regulatory role to dampen harmful self-reactive cytotoxicity by promoting IL-10 expression in CD8 T cells.

Enhanced IL‐6 transcriptional response to adenosine receptor ligands in horses with lower airway inflammation

Accumulation of extracellular adenosine has been closely associated with human asthmatic responses. However, the relevance of adenosine signalling in equine airways has not previously been investigated. To determine the expression of adenosine receptors (AR) in bronchoalveolar lavage (BAL) cells and assess the reactivity of these cells to AR ligands ex vivo, employing IL-6 as readout of adenosinergic inflammatory signalling. Eight horses with varying degrees of lower airway inflammation and 10 healthy controls were analysed. Expression of AR-subtypes in each BAL sample was determined by quantitative RT-PCR and compared to that in 13 other tissues. Bronchoalveolar lavage cells were stimulated either with the adenosine analogue NECA, CGS-21680 (A(2A) AR selective agonist) or with a combination of NECA and SCH-58261 (A(2A) AR antagonist) and IL-6 expression assessed. Bronchoalveolar lavage cells predominantly expressed A(2B) AR, with lower A(2A) AR levels and marginal A(3) AR expression; A(1) AR was not detected. This pattern was similar to that of PBMCs but different from the other tissues tested. No significant differences in AR expression in BAL cells from both groups were detected, although a trend for decreased A(2B) AR in airway-compromised horses was observed. Treatment of BAL cells with the nonselective agonist NECA upregulated IL-6 expression in cells from airway-compromised horses, but levels remained unchanged in control animals. Furthermore, blockage of A(2A) AR with SCH-58261 enhanced IL-6 mRNA induction by NECA in both groups, with higher levels in airway-compromised horses; the amplitude of this response correlated with neutrophil count. These results demonstrate the presence of an adenosine/IL-6 inflammatory axis in the bronchoalveolar milieu of airway-compromised horses. While A(2B) AR is the predominant proinflammatory AR subtype expressed, A(2A) AR appears to modulate inflammatory signalling (IL-6 expression) by adenosine. This study supports selective AR targeting as a potential therapeutic approach for the modulation of inflammation in the equine lower respiratory tract.

Induction of glucocorticoid receptor‐β expression in epithelial cells of asthmatic airways by T‐helper type 17 cytokines

Corticosteroid insensitivity in asthmatics is associated with an increased expression of glucocorticoid receptor-beta (GR-beta) in many cell types. T-helper type 17 (Th17) cytokine (IL-17A and F) expressions increase in mild and in difficult-to-treat asthma. We hypothesize that IL-17A and F cytokines alone or in combination, induce the expression of GR-beta in bronchial epithelial cells. To confirm the expression of the GR-beta and IL-17 cytokines in the airways of normal subjects and mild asthmatics and to examine the effect of cytokines IL-17A and F on the expression of GR-beta in bronchial epithelial cells obtained from normal subjects and asthmatic patients. The expression of IL-17A and F, GR-alpha and GR-beta was analysed in bronchial biopsies from mild asthmatics and normal subjects by Q-RT-PCR. Immunohistochemistry for IL-17 and GR-beta was performed in bronchial biopsies from normal and asthmatic subjects. The expression of IL-6 in response to IL-17A and F and dexamethasone was determined by Q-RT-PCR using primary airway epithelial cells from normal and asthmatic subjects. We detected significantly higher levels of IL-17A mRNA expression in the bronchial biopsies from mild asthmatics, compared with normal. GR-alpha expression was significantly lower in the biopsies from asthmatics compared with controls. The expression of IL-17F and GR-beta in biopsies from asthmatics was not significantly different from that of controls. Using primary epithelial cells isolated from normal subjects and asthmatics, we found an increased expression of GR-beta in response to IL-17A and F in the cells from asthmatics (P< or =0.05). This effect was only partially significant in the normal cells. Dexamethasone significantly decreased the IL-17-induced IL-6 expression in cells from normal individuals but not in those from asthmatics (P< or =0.05). Evidence of an increased GR-beta expression in epithelial cells following IL-17 stimulation suggests a possible role for Th17-associated cytokines in the mechanism of steroid hypo-responsiveness in asthmatic subjects.

Splenic and lung response to nonlethal systemicAspergillus fumigatusinfection in C57BL/6 mice

In this study, we investigated splenic and lung cell responses to nonlethal systemic Aspergillus fumigatus infection in mice. Apart from basic indices of spleen and lung cell activity, IL-17 expression by cells from both tissues was determined and compared to the expression of IFN-gamma and IL-4. Progressive decrease in tissue fungal burden correlated with increased spleen and lung cell activity. Increased IL-17 message was noted in spleen cells at all time points (3, 7 and 15 days post-infection; p.i.), while a modest increase in IFN-gamma mRNA expression was noted at day 3 p.i. Increased cytokine production at days 3 and 7 (IL-17) and throughout the experimental period (IFN-gamma) was found. In contrast, spleen cell IL-4 expression was considerably lower during infection, resulting in high IFN-gamma/IL-4 and IL-17/IL-4 ratios in the spleen. Pro-inflammatory cytokine response was observed in the lungs as well, but primarily as the result of increased production of IFN-gamma by lung cells in response to challenge with conidia and the absence of change in IL-4 response. Increased activity of cells from both tissues, as well as the pattern of cytokine production, created an optimal pro-inflammatory milieu for fungal eradication.

Cathelin-Related Antimicrobial Peptide (CRAMP) regulates B cell IgG1 production (84.13)

Abstract CRAMP belongs to the cathelicidin gene family, which has direct antimicrobial activity against a broad spectrum of microorganisms. Previous studies have shown that CRAMP also modifies the local inflammatory response and regulates cellular and adaptive immunity. However, a possible direct effect of CRAMP on B cells has not been studied. Using CRAMP-deficient mice, we investigated whether B cells express and respond to CRAMP. We show that all mouse B cell subsets tested, including marginal zone, follicular, B1a, and B1b cells, produced CRAMP mRNA directly ex vivo and up-regulate CRAMP upon activation. Purified CRAMP-deficient B cells produced less IgG1 in response to CD40L or LPS plus IL-4 when compared to WT B cells, and the addition of exogenous CRAMP restored the level of IgG1. CRAMP-deficiency had no effect on proliferation, survival, or class switch recombination, but resulted in a decrease in the amount of mature IgG1 mRNA and single cell IgG1 production. Surprisingly, immunization with TNP-OVA with alum resulted in an enhanced TNP-specific IgG1 memory response in CRAMP-deficient mice compared to WT B6 mice. ELISpot and PCR analysis revealed increased numbers of TNP-specific IgG1-secreting B cells and increased CD4+ T cell IL-4 expression in CRAMP-deficient mice. Taken together these results show that B cells express and respond to CRAMP positively in vitro while in vivo CRAMP appears to also indirectly alter B cells through modulation of T cell cytokine production.

A novel sphingomyelinase‐like enzyme in Ixodes scapularis tick saliva drives host CD4+ T cells to express IL‐4

Tick feeding modulates host immune responses. Tick-induced skewing of host CD4(+) T cells towards a Th2 cytokine profile facilitates transmission of tick-borne pathogens that would otherwise be neutralized by Th1 cytokines. Tick-derived factors that drive this Th2 response have not previously been characterized. In the current study, we examined an I. scapularis cDNA library prepared at 18-24 h of feeding and identified and expressed a tick gene with homology to Loxosceles spider venom proteins with sphingomyelinase activity. This I. scapularis sphingomyelinase-like (IsSMase) protein is a Mg(2+)-dependent, neutral (pH 7.4) form of sphingomyelinase. Significantly, in an in vivo TCR transgenic adoptive transfer assay IsSMase programmed host CD4(+) T cells to express the hallmark Th2 effector cytokine IL-4. IsSMase appears to directly programme host CD4 T cell IL-4 expression (as opposed to its metabolic by-products) because induced IL-4 expression was not altered when enzymatic activity was neutralized. TCR transgenic CD4 T cell proliferation (CFSE-dilution) was also significantly increased by IsSMase. Furthermore, a Th2 response is superimposed onto a virally primed Th1 response by IsSMase. Thus, IsSMase is the first identified tick molecule capable of programming host CD4(+) T cells to express IL-4.