B cell antigen presentation promotes Th2 responses and immunopathology during chronic allergic lung disease

Background

The role of B cells in allergic asthma remains undefined. One mechanism by which B cells clearly contribute to allergic disease is via the production of specific immunoglobulin, and especially IgE. Cognate interactions with specific T cells result in T cell help for B cells, resulting in differentiation and immunoglobulin secretion. Proximal to (and required for) T cell-dependent immunoglobulin production, however, is antigen presentation by B cells. While interaction with T cells clearly has implications for B cell function and differentiation, this study investigated the role that B cells have in shaping the T cell response during chronic allergic lung disease.

Methodology/Principal Findings

In these studies, we used a clinically relevant mouse model of chronic allergic lung disease to study the role of B cells and B cell antigen presentation in this disease. In these studies we present several novel findings: 1) Lung B cells from chronically allergen challenged mice up-regulated MHC II and costimulatory molecules CD40, CD80 and CD86. 2) Using in vitro studies, B cells from the lungs of allergen challenged mice could present antigen to T cells, as assessed by T cell proliferation and the preferential production of Th2 cytokines. 3) Following chronic allergen challenge, the levels of Th2 cytokines IL-4 and IL-5 in the lungs and airways were significantly attenuated in B cell −/− mice, relative to controls. 4) B cell driven Th2 responses and mucus hyper secretion in the lungs were dependent upon MHC II expression by B cells.

Conclusions/Significance

Collectively, these results provide evidence for antigen presentation as a novel mechanism by which B cells contribute to chronic allergic disease. These findings give new insight into the mechanisms by which B cells promote asthma and other chronic diseases.     

Th17 cells are involved in the local control of tumor progression in primary intraocular lymphoma

Background

Th17 cells play an important role in the pathogenesis of many autoimmune diseases, but despite some reports of their antitumor properties, too little is known about their presence and role in cancers. Specifically, knowledge is sparse about the relation of Th17 to lymphoma microenvironments and, more particularly, to the microenvironment of primary intraocular B-cell lymphoma (PIOL), an aggressive lymphoma with a poor prognosis.

Methods and Principal Findings

In this work, we investigated the presence of Th17 cells and their related cytokines in a syngeneic model of PIOL, a subtype of non-Hodgkin lymphoma. The very small number of lymphocytes trafficking in normal eyes, which represent a low background as compared to tumor-bearing eyes, allows us to develop the present model to characterize the different lymphocyte subsets present when a tumor is developing. IL-21 mRNA was expressed concomitantly with IL-17 mRNA in tumor-bearing eyes and intracellular expression of IL-17A and IL-21 in infiltrating CD4⁺ T lymphocytes. Interestingly, IL-17A production by T cells was negatively correlated with tumor burden. We also showed that IL-21 but not IL-17 inhibits tumor cell proliferation in vitro.

Conclusions

These data demonstrate that IL-17A and IL-21-producing CD4⁺ T cells, referred as Th17 cells, infiltrate this tumor locally and suggest that Th17-related cytokines may counteract tumor progression via IL-21 production. Thus, Th17 cells or their related cytokines could be considered to be a new therapeutic approach for non-Hodgkin B-cell lymphomas, particularly those with an ocular localization.     

Chronic Schistosoma japonicum Infection Reduces Immune Response to Vaccine against Hepatitis B in Mice

Background

Hepatitis B and schistosomiasis are most prevalent in Africa and Asia, and co-infections of both are frequent in these areas. The immunomodulation reported to be induced by schistosome infections might restrict immune control of hepatitis B virus (HBV) leading to more severe viral infection. Vaccination is the most effective measure to control and prevent HBV infection, but there is evidence for a reduced immune response to the vaccine in patients with chronic schistosomiasis japonica.

Methodology/Principal Findings

In this paper, we demonstrate in a mouse model that a chronic Schistosoma japonicum infection can inhibit the immune response to hepatitis B vaccine (HBV vaccine) and lead to lower production of anti-HBs antibodies, interferon-γ (IFN-γ) and interleukin-2 (IL-2). After deworming with Praziquantel (PZQ), the level of anti-HBs antibodies gradually increased and the Th2-biased profile slowly tapered. At 16 weeks after deworming, the levels of anti-HBs antibodies and Th1/Th2 cytokines returned to the normal levels.

Conclusions/Significance

The results suggest that the preexisting Th2-dominated immune profile in the host infected with the parasite may down–regulate levels of anti-HBs antibodies and Th1 cytokines. To improve the efficacy of HBV vaccination in schistosome infected humans it may be valuable to treat them with praziquantel (PZQ) some time prior to HBV vaccination.     

Th17 cytokines induce pro-fibrotic cytokines release from human eosinophils

Background

Subepithelial fibrosis is one of the most critical structural changes affecting bronchial airway function during asthma. Eosinophils have been shown to contribute to the production of pro-fibrotic cytokines, TGF-β and IL-11, however, the mechanism regulating this process is not fully understood.

Objective

In this report, we investigated whether cytokines associated with inflammation during asthma may induce eosinophils to produce pro-fibrotic cytokines.

Methods

Eosinophils were isolated from peripheral blood of 10 asthmatics and 10 normal control subjects. Eosinophils were stimulated with Th1, Th2 and Th17 cytokines and the production of TGF-β and IL-11 was determined using real time PCR and ELISA assays.

Results

The basal expression levels of eosinophil derived TGF-β and IL-11 cytokines were comparable between asthmatic and healthy individuals. Stimulating eosinophils with Th1 and Th2 cytokines did not induce expression of pro-fibrotic cytokines. However, stimulating eosinophils with Th17 cytokines resulted in the enhancement of TGF-β and IL-11 expression in asthmatic but not healthy individuals. This effect of IL-17 on eosinophils was dependent on p38 MAPK activation as inhibiting the phosphorylation of p38 MAPK, but not other kinases, inhibited IL-17 induced pro-fibrotic cytokine release.

Conclusions

Th17 cytokines might contribute to airway fibrosis during asthma by enhancing production of eosinophil derived pro-fibrotic cytokines. Preventing the release of pro-fibrotic cytokines by blocking the effect of Th17 cytokines on eosinophils may prove to be beneficial in controlling fibrosis for disorders with IL-17 driven inflammation such as allergic and autoimmune diseases.     

Restoration of regulatory and effector T cell balance and B cell homeostasis in systemic lupus erythematosus patients through vitamin D supplementation

Introduction

Systemic lupus erythematosus (SLE) is a T and B cell-dependent autoimmune disease characterized by the appearance of autoantibodies, a global regulatory T cells (Tregs) depletion and an increase in Th17 cells. Recent studies have shown the multifaceted immunomodulatory effects of vitamin D, notably the expansion of Tregs and the decrease of Th1 and Th17 cells. A significant correlation between higher disease activity and lower serum 25-hydroxyvitamin D levels [25(OH)D] was also shown.

Methods

In this prospective study, we evaluated the safety and the immunological effects of vitamin D supplementation (100 000 IU of cholecalciferol per week for 4 weeks, followed by 100 000 IU of cholecalciferol per month for 6 months.) in 20 SLE patients with hypovitaminosis D.

Results

Serum 25(OH)D levels dramatically increased under vitamin D supplementation from 18.7±6.7 at day 0 to 51.4±14.1 (p<0.001) at 2 months and 41.5±10.1 ng/mL (p<0.001) at 6 months. Vitamin D was well tolerated and induced a preferential increase of naïve CD4⁺ T cells, an increase of regulatory T cells and a decrease of effector Th1 and Th17 cells. Vitamin D also induced a decrease of memory B cells and anti-DNA antibodies. No modification of the prednisone dosage or initiation of new immunosuppressant agents was needed in all patients. We did not observe SLE flare during the 6 months follow-up period.

Conclusions

This preliminary study suggests the beneficial role of vitamin D in SLE patients and needs to be confirmed in randomized controlled trials.     

T Cell Activation and Proinflammatory Cytokine Production in Clinically Cured Tuberculosis Are Time-Dependent and Accompanied by Upregulation of IL-10

Background

Th1 cytokines are essential for the control of M. tuberculosis infection. The role of IL-10 in tuberculosis is controversial and there is an increasing body of evidence suggesting that the relationship between Th1 cytokines and IL-10 is not as antagonistic as it was first believed, and that these cytokines may complement each other in infectious diseases.

Methods

The present study evaluated the activating capacity of CD4+ and CD8+ T cell repertoire in response to antigen stimulation through the expression of CD69 using Flow Cytometry, as well as the functionality of PBMCs by determining the cytokine profile in patients with active tuberculosis and in clinically cured patients after in vitro stimulation using ELISA. Treated patients were subdivided according to time after clinical cure (<12 months or >12 months post-treatment).

Results

We observed that T cell activation was higher in TB-treated patients, especially CD8+ T cell activation in TB-Treated >1 year. Th1 cytokines were significantly higher in TB-Treated, and the levels of IFN-γ and TNF-α increased continuously after clinical cure. Moreover, IL-10 production was significantly higher in cured patients and it was also enhanced in cured patients over time after treatment. Th17, Th2 and Th22 cytokines showed no statistically significant differences between Healthy Donors, Active-TB and TB-Treated.

Conclusions

This study describes a scenario in which potentiation of CD4+ and CD8+ T cell activation and increased Th1 cytokine production are associated with the clinical cure of tuberculosis in the absence of significant changes in Th2 cytokine production and is accompanied by increased production of IL-10. In contrast to other infections with intracellular microorganisms, this response occurs later after the end of treatment.     

Active systemic lupus erythematosus is associated with a reduced cytokine production by B cells in response to TLR9 stimulation

Introduction

Systemic lupus erythematosus (SLE) is an autoimmune disease associated with a break in self-tolerance reflected by a production of antinuclear autoantibodies. Since autoantibody production can be activated via nucleic acid Toll-like receptor 9 (TLR9), the respective pathway has been implicated in the development of SLE and pathogenic B cell responses. However, the response of B cells from SLE patients to TLR9 stimulation remains incompletely characterized.

Methods

In the current study, the response of B cells from SLE patients and healthy donors upon TLR9 stimulation was analyzed in terms of proliferation and cytokine production and correlated with the lupus disease activity and anti-dsDNA titers.

Results

B cells from SLE patients showed a reduced response to TLR9 agonist compared to B cells from healthy donors in terms of proliferation and activation. B cells from SLE patients with higher disease activity produced less interleukin (IL)-6, IL-10, vascular endothelial growth factor, and IL-1ra than B cells from healthy donors. Further analyses revealed an inverse correlation of cytokines produced by TLR9-stimulated B cells with lupus disease activity and anti-dsDNA titer, respectively.

Conclusion

The capacity of B cells from lupus patients to produce cytokines upon TLR9 engagement becomes less efficient with increasing disease activity, suggesting that they either enter an exhausted state or become tolerant to TLR stimulation for cytokine production when disease worsens.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-014-0477-1) contains supplementary material, which is available to authorized users.     

Contact Sensitizers Induce Skin Inflammation via ROS Production and Hyaluronic Acid Degradation

Background

Allergic contact dermatitis (ACD) represents a severe health problem with increasing worldwide prevalence. It is a T cell-mediated skin disease induced by protein-reactive organic and inorganic chemicals. A key feature of contact allergens is their ability to trigger an innate immune response that leads to skin inflammation. Previous evidence from the mouse contact hypersensitivity (CHS) model suggests a role for endogenous activators of innate immune signaling. Here, we analyzed the role of contact sensitizer induced ROS production and concomitant changes in hyaluronic acid metabolism on CHS responses.

Methodology/Principal Findings

We analyzed in vitro and in vivo ROS production using fluorescent ROS detection reagents. HA fragmentation was determined by gel electrophoresis. The influence of blocking ROS production and HA degradation by antioxidants, hyaluronidase-inhibitor or p38 MAPK inhibitor was analyzed in the murine CHS model. Here, we demonstrate that organic contact sensitizers induce production of reactive oxygen species (ROS) and a concomitant breakdown of the extracellular matrix (ECM) component hyaluronic acid (HA) to pro-inflammatory low molecular weight fragments in the skin. Importantly, inhibition of either ROS-mediated or enzymatic HA breakdown prevents sensitization as well as elicitation of CHS.

Conclusions/Significance

These data identify an indirect mechanism of contact sensitizer induced innate inflammatory signaling involving the breakdown of the ECM and generation of endogenous danger signals. Our findings suggest a beneficial role for anti-oxidants and hyaluronidase inhibitors in prevention and treatment of ACD.     

Th17 cells and IL-17 in protective immunity to vaginal candidiasis

Background

Th17 cells play a major role in coordinating the host defence in oropharyngeal candidiasis. In this study we investigated the involvement of the Th17 response in an animal model of vulvovaginal candidiasis (VVC).

Methods

To monitor the course of infection we exploited a new in vivo imaging technique.

Results

i) The progression of VVC leads to a strong influx of neutrophils in the vagina soon after the challenge which persisted despite the resolution of infection; ii) IL-17, produced by vaginal cells, particularly CD4 T cells, was detected in the vaginal wash during the infection, reaching a maximum 14 days after the challenge; iii) The amount and kinetics of IL-23 in vaginal fluids were comparable to those in vaginal cells; iv) The inhibition of Th17 differentiation led to significant inhibition of IL-17 production with consequent exacerbation of infection; v) An increased production of βdefensin 2 was manifested in cells of infected mice. This production was strongly reduced when Th17 differentiation was inhibited and was increased by rIL-17 treatment.

Conclusions

These results imply that IL-17 and Th17, along with innate antimicrobial factors, have a role in the immune response to vaginal candidiasis.     

In Situ Immune Response in Human Chromoblastomycosis – A Possible Role for Regulatory and Th17 T Cells

Background

Chromoblastomycosis is a chronic fungal infection that affects skin and subcutaneous tissue. Lesions can be classified in tumorous, verrucous, cicatricial and plaque type. The cellular immune response in the severe form of the disease seems to correlate with a Th2 pattern of cytokines. The humoral immune response also seems to play a role. We intended to explore the populations of regulatory T cells and the Th17 pattern.

Methodology

Twenty-three biopsies of verrucous form were obtained from patients with clinical, culture and histopathological diagnostic of chromoblastomycosis, without treatment. It was performed an immunohistochemistry method to detect Foxp3, CD25, TGF-β, IL-6, IL-17 and IL-23.

Principal findings

IL-17 was the only cytokine with high expression in CBM when compared to normal skin. The expression of Treg cells, TGF- β, IL-6 and IL-23 were similar to normal skin.

Conclusions/Significance

The constitution of a local immune response with high expression of IL-17 and low expression of other cytokines could be at least in part, an attempt to help the immune system against fungal infection. On the other hand, high levels of local immune response mediated by Th17 profile could overcome the role of Treg cells. The inefficient immunomodulation as a consequence of the unbalance by Treg/Th17 cells seems to corroborate with the less effective immune response against fungi.     

Elevation of IL-6 in the allergic asthmatic airway is independent of inflammation but associates with loss of central airway function

Background

Asthma is a chronic inflammatory disease of the airway that is characterized by a Th2-type of immune response with increasing evidence for involvement of Th17 cells. The role of IL-6 in promoting effector T cell subsets suggest that IL-6 may play a functional role in asthma. Classically IL-6 has been viewed as an inflammatory marker, along with TNFα and IL-1β, rather than as regulatory cytokine.

Objective

To investigate the potential relationship between IL-6 and other proinflammatory cytokines, Th2/Th17 cytokines and lung function in allergic asthma, and thus evaluate the potential role of IL-6 in this disease.

Methods

Cytokine levels in induced sputum and lung function were measured in 16 healthy control and 18 mild-moderate allergic asthmatic subjects.

Results

The levels of the proinflammatory biomarkers TNFα and IL-1β were not different between the control and asthmatic group. In contrast, IL-6 levels were specifically elevated in asthmatic subjects compared with healthy controls (p < 0.01). Hierarchical regression analysis in the total study cohort indicates that the relationship between asthma and lung function could be mediated by IL-6. Among Th2 cytokines only IL-13 (p < 0.05) was also elevated in the asthmatic group, and positively correlated with IL-6 levels (r_S = 0.53, p < 0.05).

Conclusions

In mild-moderate asthma, IL-6 dissociates from other proinflammatory biomarkers, but correlates with IL-13 levels. Furthermore, IL-6 may contribute to impaired lung function in allergic asthma.     

Src Kinases Are Required for a Balanced Production of IL-12/IL-23 in Human Dendritic Cells Activated by Toll-Like Receptor Agonists

Background

Pathogen recognition by dendritic cells (DC) is crucial for the initiation of both innate and adaptive immune responses. Activation of Toll-like Receptors (TLRs) by microbial molecular patterns leads to the maturation of DC, which present the antigen and activate T cells in secondary lymphoid tissues. Cytokine production by DC is critical for shaping the adaptive immune response by regulating T helper cell differentiation. It was previously shown by our group that Src kinases play a key role in cytokines production during TLR4 activation in human DC.

Principal Findings

In this work we investigated the role of Src kinases during different TLRs triggering in human monocyte-derived DC (MoDC). We found that Src family kinases are important for a balanced production of inflammatory cytokines by human MoDC upon stimulation of TLR3 and 8 with their respective agonists. Disruption of this equilibrium through pharmacological inhibition of Src kinases alters the DC maturation pattern. In particular, while expression of IL-12 and other inflammatory cytokines depend on Src kinases, the induction of IL-23 and co-stimulatory molecules do not. Accordingly, DC treated with Src inhibitors are not compromised in their ability to induce CD4 T cell proliferation and to promote the Th17 subset survival but are less efficient in inducing Th1 differentiation.

Conclusions

We suggest that the pharmacological modulation of DC maturation has the potential to shape the quality of the adaptive immune response and could be exploited for the treatment of inflammation-related diseases.     

Imbalanced Frequencies of Th17 and Treg Cells in Acute Coronary Syndromes Are Mediated by IL-6-STAT3 Signaling

Aims

Extensive evidence suggests inflammatory components participate in the pathogenic processes of acute coronary syndromes (ACS). In this study, we aimed to elucidate the role and mechanism underlying the imbalance of Th17 and Treg cell peripheral populations in the pathogenesis of ACS.

Methods and Results

Using a flow cytometric analysis, we observed a significantly increased frequency of Th17 cells and a concurrently decreased CD4⁺CD25⁺Foxp3⁺ Treg cells in patients with ACS. To elucidate the mechanism of Th17/Treg imbalance in ACS, 22 inflammatory cytokines were measured using multiplexed immunobead-based assays. Of six elevated cytokines in ACS patients, only IL-6 was positively correlated with a higher Th17 cell level (r = 0.39, P<0.01). Relying on IL-6 stimulating and neutralizing studies, we demonstrated a direct role for IL-6 in sera from ACS patients with an increased frequency of Th17 cells. IL-6 induces the differentiation of Th17 cells from naïve CD4⁺ T cells through STAT3 activation and RORγt induction. However, we observed that high levels of TGF-β1 inhibited IL-6-dependent Th17 cell differentiation, indicating a complex interplay between the two cytokines in the control of Th17 and Treg cell populations.

Conclusions

Our results demonstrate the role of IL-6-STAT3 signaling in ACS through increased Th17 cell differentiation. These findings indicate that IL-6 neutralizing strategies could present novel therapeutic avenues in the treatment of ACS.     

Decreased ratio of Treg cells to Th17 cells correlates with HBV DNA suppression in chronic hepatitis B patients undergoing entecavir treatment

Background

Treatment with nucleotide analogs is known to be effective in inhibiting HBV replication; however, patients with chronic hepatitis B (CHB) often show a wide range of clinical responses to these drugs. Therefore, the identification of an early immunologic marker associated with the clinical outcomes in such cases is critical for the improved clinical management. In our study, we aimed to investigate whether the viral load in CHB patients affected the ratio of the number of regulatory T cells (Tregs) to the number of interleukin-17-producing helper (Th17) cells. Further, we evaluated the clinical implications of the alterations in this ratio.

Methodology/Principal Findings

Nine patients seropositive for hepatitis B e antigen received entecavir monotherapy for 12 months and the percentages of Tregs and Th17 cells as well as the HBV-specific IL-17 productions in these patients were longitudinally analyzed. The entecavir-induced suppression of HBV replication was accompanied by a rapid increase in the number of Th17 cells, together with a decrease in Treg cells, which lead to a significant reduction of Treg/Th17 ratios. In addition, peripheral blood mononuclear cells (PBMCs) exhibited a decreased IL-17 production upon stimulation with the HBV core antigen in vitro.

Conclusions

The inhibition of viral replication results in an increase in Th17 cells and concomitant decrease in Treg cells. This imbalance of Treg cells to Th17 cells might have an important role in HBV persistence during entecavir treatment.     

Expansion of Pathogen-Specific Mono- and Multifunctional Th1 and Th17 Cells in Multi-Focal Tuberculous Lymphadenitis

Background

Th1 and Th17 responses are known to play an important role in immunity to pulmonary tuberculosis (PTB), although little is known about their role in extrapulmonary forms of tuberculosis (TB).

Methods

To identify the role of Th1, Th17, and Th22 cells in multi-focal TB lymphadenitis (TBL), we examined mycobacteria–specific immune responses in the whole blood of individuals with PTB (n = 20) and compared them with those with TBL (n = 25).

Results

Elevated frequencies of CD4⁺ T cells expressing IFN- γ, TNF-α, and IL-2 were present in individuals with TBL compared with those with PTB at baseline and in response to ESAT-6 and CFP-10. Similarly, increased frequencies of CD4⁺ T cells expressing IL-17A, IL-17F, and IFN-γ were also present in individuals with TBL at baseline and following ESAT-6 and CFP-10 stimulation although no significant difference in frequency of Th22 cells was observed. Finally, frequencies of Th1 (but not Th17) cells exhibited a significantly negative correlation with natural regulatory T cell frequencies at baseline.

Conclusions

Multi-focal TB lymphadenitis is therefore characterized by elevated frequencies of Th1 and Th17 cells, indicating that Th1 and Th17 responses in TB disease are probably correlates of disease severity rather than of protective immunity.     

Differences in allergen-induced T cell activation between allergic asthma and rhinitis: Role of CD28, ICOS and CTLA-4

Background

Th2 cell activation and T regulatory cell (Treg) deficiency are key features of allergy. This applies for asthma and rhinitis. However with a same atopic background, some patients will develop rhinitis and asthma, whereas others will display rhinitis only. Co-receptors are pivotal in determining the type of T cell activation, but their role in allergic asthma and rhinitis has not been explored. Our objective was to assess whether allergen-induced T cell activation differs from allergic rhinitis to allergic rhinitis with asthma, and explore the role of ICOS, CD28 and CTLA-4.

Methods

T cell co-receptor and cytokine expressions were assessed by flow cytometry in PBMC from 18 house dust mite (HDM) allergic rhinitics (R), 18 HDM allergic rhinitics and asthmatics (AR), 13 non allergic asthmatics (A) and 20 controls, with or without anti-co-receptors antibodies.

Results

In asthmatics (A+AR), a constitutive decrease of CTLA-4+ and of CD4+CD25+Foxp3+ cells was found, with an increase of IFN-γ+ cells. In allergic subjects (R + AR), allergen stimulation induced CD28 together with IL-4 and IL-13, and decreased the proportion of CTLA-4+, IL-10+ and CD4+CD25+Foxp3+ cells. Anti-ICOS and anti-CD28 antibodies blocked allergen-induced IL-4 and IL-13. IL-13 production also involved CTLA-4.

Conclusions

T cell activation differs between allergic rhinitis and asthma. In asthma, a constitutive, co-receptor independent, Th1 activation and Treg deficiency is found. In allergic rhinitis, an allergen-induced Treg cell deficiency is seen, as well as an ICOS-, CD28- and CTLA-4-dependent Th2 activation. Allergic asthmatics display both characteristics.     

Immune Response to Lactobacillus plantarum Expressing Borrelia burgdorferi OspA Is Modulated by the Lipid Modification of the Antigen

Background

Over the past decade there has been increasing interest in the use of lactic acid bacteria as mucosal delivery vehicles for vaccine antigens, microbicides and therapeutics. We investigated the mechanism by which a mucosal vaccine based in recombinant lactic acid bacteria breaks the immunological tolerance of the gut in order to elicit a protective immune response.

Methodology/Principal Findings

We analyzed how the lipid modification of OspA affects the localization of the antigen in our delivery vehicle using a number of biochemistry techniques. Furthermore, we examined how OspA-expressing L. plantarum breaks the oral tolerance of the gut by stimulating human intestinal epithelial cells, peripheral blood mononuclear cells and monocyte derived dendritic cells and measuring cytokine production. We show that the leader peptide of OspA targets the protein to the cell envelope of L. plantarum, and it is responsible for protein export across the membrane. Mutation of the lipidation site in OspA redirects protein localization within the cell envelope. Further, we show that lipidated-OspA-expressing L. plantarum does not induce secretion of the pro-inflammatory cytokine IL-8 by intestinal epithelial cells. In addition, it breaks oral tolerance of the gut via Th1/Th2 cell mediated immunity, as shown by the production of pro- and anti-inflammatory cytokines by human dendritic cells, and by the production of IgG2a and IgG1 antibodies, respectively.

Conclusions/Significance

Lipid modification of OspA expressed in L. plantarum modulates the immune response to this antigen through a Th1/Th2 immune response.     

Airway epithelial cells initiate the allergen response through transglutaminase 2 by inducing IL-33 expression and a subsequent Th2 response

Background

Transglutaminase 2 (TG2) is a post-translational protein-modifying enzyme that catalyzes the transamidation reaction, producing crosslinked or polyaminated proteins. Increased TG2 expression and activity have been reported in various inflammatory conditions, such as rheumatoid arthritis, inflammation-associated pulmonary fibrosis, and autoimmune encephalitis. In particular, TG2 from epithelial cells is important during the initial inflammatory response in the lung. In this study, we evaluated the role of TG2 in the pathogenesis of allergic asthma, particularly whether TG2 affects initial activation signaling leading to Th2 differentiation against antigens.

Methods

We induced allergic asthma by ovalbumin sensitization and intranasal challenge in wild-type (WT) BALB/c and TG2-deficient mice. Broncheoalveolar lavage fluid cells and intracellular cytokine production were analyzed by flow cytometry. Interleukin (IL)-33 and TG2 expression in lung epithelial cells was detected by confocal microscopy.

Results

Airway responsiveness was attenuated in TG2-deficient mice compared to that in the WT control. In addition, recruitment of eosinophils and Th2 and Th17 differentiation decreased in TG2-deficient mice. Treatment with cysteamine, a transglutaminase inhibitor, also reduced airway hypersensitivity, inflammatory cell recruitment, and T helper cell differentiation. TG2-deficient mice showed reduced IL-33 expression following induction of allergic asthma compared to those in the WT control.

Conclusions

We found that pulmonary epithelial cells damaged by allergens triggered TG2-mediated IL-33 expression leading to type 2 responses by recruiting both innate and adaptive arms of the immune system.     

The presence of IL-17A and T helper 17 cells in experimental mouse brain tumors and human glioma

Background

Recently, CD4⁺IL-17A⁺ T helper 17 (Th17) cells were identified and reported in several diseased states, including autoimmunity, infection and various peripheral nervous system tumors. However, the presence of Th17 in glia-derived tumors of the central nervous system has not been studied.

Methodology/Principal Findings

In this report, we demonstrate that mRNA expression for the Th17 cell cytokine IL-17A, as well as Th17 cells, are present in human glioma. The mRNA expression for IL-17A in glioma was recapitulated in an immunocompetent mouse model of malignant glioma. Furthermore, the presence of Th17 cells was confirmed in both human and mouse glioma. Interestingly, some Th17 cells present in mouse glioma co-expressed the Th1 and Th2 lineage markers, IFN-γ and IL-4, respectively, but predominantly co-expressed the Treg lineage marker FoxP3.

Conclusions

These data confirm the presence of Th17 cells in glia-derived CNS tumors and provide the rationale for further investigation into the role of Th17 cells in malignant glioma.