CD38+ B cells affect immunotherapy for allergic rhinitis.

BACKGROUND: Allergen-specific immunotherapy (AIT) is the mainstay in the treatment of allergic diseases, but the therapeutic effects of AIT need to be improved. CD38+ B cells are an immune cell fraction involved in the pathogenesis of allergic diseases as well as in immune regulation. OBJECTIVE: We sought to elucidate the role of antigen-specific CD38+ B cells in AIT. METHODS: An analysis was carried out on AIT results of 48 patients with perennial allergic rhinitis (AR), among which peripheral blood immune cells were analyzed by flow cytometry; serum cytokine levels were determined by ELISA. An AR murine model was developed to test the role of CD38+ B cells in AIT. RESULTS: A fraction of antigen-specific CD38+ B cell was detected in AR patients. CD38+ B-cell frequency was negatively correlated with the therapeutic effects of AIT. A negative correlation was detected between the CD38+ B-cell frequency and regulatory T-cell frequency in AR patients treated with AIT. Exposure to specific antigens induced CD38+ B cells to produce IL-6, that converted Treg cells to TH17 cells. Coadministration of anti-CD38 antibody significantly promoted the therapeutic effects of AIT. CONCLUSIONS: Antigen-specific CD38+ B cells compromise AIT effects by producing IL-6 to convert regulatory T cells to TH17 cells. Inhibition of CD38+ B cells promotes the effects of AIT.

Propionic acid regulates immune tolerant properties in B Cells.

Interleukin 10 (IL-10)-producing B cells (B10 cells) are a canonical cell fraction for regulating other activities of immune cells. Posttranscriptional modification of IL-10 in B10 cells is not yet fully understood. Short-chain fatty acids play an important role to regulate the functions of immune cells. This study aims to clarify the role of propionic acid (PA), a short-chain fatty acid, in regulating the expression of IL-10 in B10 cells. Blood samples were collected from patients with food allergy (FA) and healthy subjects. Serum and cellular components were prepared with the samples, and analysed by enzyme-linked immunosorbent assay and flow cytometry, respectively. The results showed that serum PA levels were lower in FA patients. PA concentrations were negatively correlated with serum cytokine Th2 concentrations, specific IgE concentrations in serum and skin prick test results. The peripheral frequency of B10 cells and the production of IL-10 in B cells were also associated with serum PA concentrations. Activation of B cells by CpG induced the production of IL-10 and tristetretrprolin (TTP), in which TTP caused the spontaneous decay of IL-10 mRNA. PA was necessary to stabilize the IL-10 mRNA in B cells by inducing the production of granzyme B, which resulted in the degradation of the IL-10 mRNA. Administration of PA attenuated FA response in mice by maintaining homeostasis of B10 cells. In conclusion, PA is needed to stabilize the expression of IL-10 in B10 cells. PA administration can mitigate experimental FA by maintaining B10 cell functions.

Dust-mite-derived protein disulfide isomerase suppresses airway allergy by inducing tolerogenic dendritic cells.

House dust mites (HDMs) are a potent allergen source that are commonly found in human living environments. While HDMs are known to induce allergic diseases in humans, such as asthma, its other biological activities related to human health are less understood. Our laboratory recently purified the HDM protein PDI (protein disulfide isomerase). In this study, we assess the role of PDI in contributing to immune regulation. Using mass spectrometry, we analyzed the complexes of DEC205 and HDM extracts, and the role of PDI in the induction of tolerogenic dendritic cells (DCs) was assessed in human cell culture experiments and verified in a murine model. We found that more than 20 HDM-derived proteins, including PDI, bound to DCs by forming complexes with DEC205. Additionally, DEC205-mediated the endocytosis of PDI. HDM-derived PDI (HDM-PDI) promoted Foxp3 expression in DCs. HDM-PDI-primed DCs also showed tolerogenic properties that induced regulatory T cell development, indicating that the primed DCs were tolerogenic DCs. Our results suggested that the PDI/DEC205/TIEG1/Foxp3 signal pathway activation was involved in the HDM-PDI-induced Foxp3 expression in DCs. Finally, we found that HDM-PDI competitively counteracted the Th2 cytokines to restore DC's tolerogenicity, and administration of HDM-PDI could suppress experimental asthma. In conclusion, our data suggest that HDM-PDI contributes to immune regulation by inducing tolerogenic DC development. Administration of HDM-PDI can alleviate experimental asthma. These findings demonstrate that HDM-PDI has translational potential to be used in the treatment of immune disorders such as asthma.

FcγRI plays a critical role in patients with ulcerative colitis relapse.

Ulcerative colitis (UC) is a disease that frequently relapses and affects more than 0.1% general population; the underlying mechanism is poorly understood. Published data show that polymorphonuclear neutrophils (PMN) contribute to the pathogenesis of UC. This study aims to identify antigen (Ag)-specific PMNs and investigate their role in UC relapse. In this study, the correlation between PMN activities and UC relapse was assessed in a group of UC patients. A UC mouse model was developed to expand the findings of UC patient study. The results showed that a positive correlation was detected between the high PMN activities and the food Ag-specific IgG amounts in colon biopsies of UC patients. UC patient-derived Ag-specific PMNs could be activated upon exposure to food specific Ag. The Ag/FcγRI complexes were detected on the surface of PMNs in UC patients. Re-exposure of sensitized PMNs to specific Ag triggered PMN activation and induced UC-like inflammation in the mouse colon. We conclude that FcγRI plays a critical role in UC relapse. Inhibition of FcγRI can efficiently inhibits experimental UC.

Modulating oxidative stress counteracts specific antigen-induced regulatory T-cell apoptosis in mice.

Treg are known to have a central role in orchestrating immune responses, but less is known about the destiny of Treg after being activated by specific Ags. This study aimed to investigate the role of superoxide dismutase, an active molecule in the regulation of oxidative stress in the body, in the prevention of Treg apoptosis induced by specific Ags. Ag-specific Tregs were isolated from the DO11.10 mouse intestine. A food allergy mouse model was developed with ovalbumin as the specific Ag and here, we observed that exposure to specific Ag induced Treg apoptosis through converting the precursor of TGF-ß to its mature form inside the Tregs. Oxidative stress was induced in Tregs upon exposure to specific Ags, in which Smad3 bound the latency-associated peptide to induce its degradation, converting the TGF-ß precursor to its mature form, TGF-ß. Suppressing oxidative stress in Tregs alleviated the specific Ag-induced Treg apoptosis in in vitro experiments and suppressed experimental food allergy by preventing the specific Ag-induced Treg apoptosis in the intestine. In conclusion, exposure to specific Ags induces Treg apoptosis and it can be prevented by upregulating superoxide dismutase or suppressing reactive oxidative species in Tregs.

Characterization of allergic inflammation in chronic uterine cervicitis.

Female genital tract chronic inflammation is common in clinics; the pathogenesis is not fully understood yet. House dust mite (HDM) involves the pathogenesis of many chronic diseases in human. This study aims to identify HDM-specific allergic response in the cervix of patients with cervical inflammation. Patients (n = 80) with chronic cervicitis (CC) and non-CC control (NC) subjects (n = 80) were recruited into this study. Vaginal lavage fluids (VLF) were collected from CC patients and NC subjects. Cellular components and fluid part of VLF were separated by centrifugation, and analyzed by flow cytometry and enzyme-linked immunosorbent assay. We found that a portion (52 out of 80) of CC patients responded to HDM, manifesting positive skin prick test, and HDM-specific IgE and IgG was detected in the VLF (designated CCp patients). VLF of CCp patients showed a Th2-dominant profile. HDM-specific Th2 cells were detected in VLF in CCp patients. Exposure to HDM in the culture induced proinflammatory cytokine release from CCp VLF CD4+ T cells. Exposure to CCp VLF CD4+ T cell-conditioned medium induced de novo Th2 response. Direct exposure to HDM induced allergic response in the cervix of CCp patients. In summary, a portion of CC patients respond to HDM challenge in the cervix. Exposure to HDM induces an allergy-like response in the cervix of CCp patients.

Flagellin maintains eosinophils in the intestine.

Eosinophils (Eos) are the major effector cells in allergic response. The regulation of Eo is not fully understood yet. Flagellin (FGN) has immune regulatory functions. This study aims to elucidate the role of FGN in maintaining Eo at the static status in the intestinal tissues. A mouse food allergy (FA) model was developed. Eo mediator levels in the serum or culture supernatant or intestinal lavage fluids were assessed and used as an indicator of Eo activation. The results showed that less FGN amounts were detected in the FA mouse intestinal tissues, that were negatively correlated with the Eo activation. Mast cell-derived chymase bound FGN to induce FGN degradation. FGN formed complexes with FcγRI on Eos to prevent specific antigens from binding FcγRI, and thus, to prevent Eo activation. Administration of FGN efficiently alleviated experimental FA. In conclusion, FGN plays a critical role in maintaining Eos at static status in the intestine. Administration of FGN can alleviate experimental FA. FGN may be a novel drug candidate to be used in the treatment of Eo-related diseases.

Single-Cell RNA Sequencing to Dissect the Immunological Network of Autoimmune Myocarditis.

BACKGROUND: Myocarditis can develop into dilated cardiomyopathy, which may require heart transplantation. The immunological network of myocarditis phases remains unknown. This study aimed to investigate the immunological network during the transition from myocarditis to cardiomyopathy and to identify the genes contributing to the inflammatory response to myocarditis. METHODS: Mice were treated with myosin heavy chain-α peptides to generate an experimental autoimmune myocarditis (EAM) model. We performed single-cell RNA sequencing analysis of Cd45+ cells extracted from mouse hearts during different EAM phases, including normal control, acute inflammatory, subacute inflammatory, and myopathy phases. Human heart tissues were collected from the surgically removed hearts of patients who had undergone heart transplantation. RESULTS: We identified 26 cell subtypes among 34 665 cells. Macrophages constituted the main immune cell population at all disease phases (>60%), and an inflammation-associated macrophage cluster was identified in which the expression of Hif1a-regulated genes was upregulated. The neutrophil population was increased after the induction of EAM, and neutrophils then released Il-1 to participate in the EAM process. T cells were observed at the highest percentage at the subacute inflammatory phase. T-helper 17 cells, in which the expression of Hif1a-regulated genes was upregulated, constituted the main T-cell population detected at the acute inflammatory phase, whereas regulatory T cells were the main T-cell population detected at the subacute inflammatory phase, and γδ T cells releasing Il-17 were the main T-cell population observed at the myopathy phase. Moreover, the Hif1a expression level correlated with the extent of inflammation. In addition, PX-478 could alleviate the inflammatory responses of the different EAM phases. Last, HIF1A was expressed at higher levels in patients with acute autoimmune myocarditis than in patients with dilated cardiomyopathy and healthy control subjects. CONCLUSIONS: We present here a comprehensive single-cell landscape of the cardiac immune cells in different EAM phases. In addition, we elucidate the contribution of Hif1a to the inflammatory response through the regulation of immune cell activity, particularly of macrophage cluster 2 and T-helper 17 cells. Moreover, an Hif1a inhibitor alleviated inflammatory cell infiltration of the EAM model and may serve as a potential therapeutic target in the clinic.

Epithelial cell-derived CD83 restores immune tolerance in the airway mucosa by inducing regulatory T-cell differentiation.

The mechanism of generation of regulatory T cells (Treg) remains incompletely understood. Recent studies show that CD83 has immune regulatory functions. This study aims to investigate the role of epithelial cell-derived CD83 in the restoration of immune tolerance in the airway mucosa by inducing the Treg differentiation. In this study, CD83 and ovalbumin (OVA)-carrying exosomes were generated from airway epithelial cells. An airway allergy mouse model was developed to test the role of CD83/OVA-carrying exosomes in the suppression of airway allergy by inducing Treg generation. We observed that mouse airway epithelial cells expressed CD83 that could be up-regulated by CD40 ligand. The CD83 deficiency in epithelial cells retarded the Treg generation in the airway mucosa. CD83 up-regulated transforming growth factor-ß-inducible early gene 1 expression in CD4+ T cells to promote Foxp3 expression. Exposure of primed CD4+ T cells to CD83/OVA-carrying exosomes promoted antigen-specific Treg generation. Administration of CD83/OVA-carrying exosomes inhibited experimental airway allergic response. In summary, airway epithelial cells express CD83 that is required in the Treg differentiation in the airway mucosa. Administration of CD83/OVA-carrying exosomes can inhibit airway allergy that has the translation potential in the treatment of airway allergic disorders.

Interaction between Ras and Bcl2L12 in B cells suppresses IL-10 expression.

The pathogenesis of recurrent tonsillitis is to be further investigated. B cell-derived interleukin (IL)-10 plays a critical role in immune regulation. Ras activation plays an important role in cancer and many immune disorders. This study aims to investigate the role of Ras activation in down regulating IL-10 expression in tonsillar B cells. Surgically removed tonsil tissues were collected from patients with recurrent acute tonsillar inflammation; B cells were isolated from the tonsillar tissues by flow cytometry sorting to be analyzed by the Ras-specific enzyme-linked immunosorbent assay and pertinent immunological approaches. We found that, compared to peripheral B cells (pBC), B cells isolated from the tonsillar tissues with recurrent inflammation (tBC) showed higher Ras activation, lower IL-10 expression and higher Bcl2L12 expression. Bcl2L12 formed a complex with GAP (GTPase activating protein) to prevent Ras from deactivating. The Ras activation triggered the MAPK/Sp1 pathway to promote the Bcl2L12 expression in B cells. Bcl2L12 prevented the IL-10 expression in tBCs, that was counteracted by inhibition of Ras or the Ras signal transduction pathway. In conclusion, Bcl2L12 interacts with Ras activation to compromise immune tolerance in the tonsils by inhibiting the IL-10 expression in tBCs. Inhibition of Bcl2L12 can restore the IL-10 expression in tBCs.

Retinoblastoma cell-derived Twist protein promotes regulatory T cell development.

BACKGROUND: The development of tumor tissue-infiltrating regulatory T cell (Treg) is incompletely understood. This study investigates the role of retinoblastoma cell (Rbc)-derived Twist­related protein 1 (Twist) in the Treg development. METHODS: The surgically removed Rb tissues were collected. Rbcs were cultured with CD4+ T cells to assess the role of Rbc-derived Twist in the Treg generation. RESULTS: We found that more than 90% Rbcs expressed Twist. Foxp3+ Tregs were detected in the Rb tissues that were positively correlated with the Twist expression in Rbcs, negatively associated with Rb patient survival and sight survival. Treating Rbcs with hypoxia promoted the Twist expression that could be detected in the cytoplasm, nuclei and on the cell surface. Twist activated CD4+ T cells by binding the TLR4/myeloid differentiation factor 2 complex and promoted the transforming growth factor-ß-inducible early gene 1 product and Foxp3 expression. These Rbc-induced Foxp3+ Tregs showed immune-suppressive function on CD8+ T cell proliferation. CONCLUSIONS: Rbcs express Twist, that induces IL-4+ Foxp3+ Tregs; the latter can inhibit CD8+ cytotoxic T cell activities. Therefore, Twist may play an important role in the pathogenesis of Rb.

Cross-reactive antibodies against dust mite-derived enolase induce neutrophilic airway inflammation.

BACKGROUND AND AIMS: Neutrophilic inflammation is a hallmark of some specific asthma phenotypes; its aetiology is not yet fully understood. House dust mite (HDM) is the most common factor in the pathogenesis of airway inflammation. This study aims to elucidate the role of cross-antibodies against HDM-derived factors in the development of neutrophilic inflammation in the airway. METHODS: Blood samples were collected from asthma patients with chronic neutrophilic asthma for analysis of HDM-specific cross-reactive antibodies. The role of an antibody against HDM-derived enolase (EnoAb) in the impairment of airway epithelial barrier function and induction of airway inflammation was assessed in a cell culture model and an animal model. RESULTS: High similarity (72%) of the enolase gene sequences was identified between HDM and human. Serum EnoAb was detected in patients with chronic neutrophilic asthma. The EnoAb bound to airway epithelial cells to form complexes with enolase, which activated complement, impaired airway epithelial barrier functions and induced neutrophilic inflammation in the airway tissues. CONCLUSIONS: HDM-derived enolase can induce specific cross-antibodies in humans, which induce neutrophilic inflammation in the airway.

T cell activator-carrying extracellular vesicles induce antigen-specific regulatory T cells.

The mechanism of antigen-specific regulatory T cell (Treg ) induction is not yet fully understood. Curcumin has an immune regulatory function. This study aims to induce antigen-specific Tregs by employing extracellular vesicles (EVs) that carry two types of T cell activators. Two types of T cell activators, ovalbumin (OVA)/major histocompatibility complex-II (MHC-II) and tetramethylcurcumin (FLLL31) (a curcumin analog) were carried by dendritic cell-derived extracellular vesicles, designated OFexo. A murine model of allergic rhinitis (AR) was developed with OVA as the specific antigen. AR mice were treated with a nasal instillation containing OFexo. We observed that OFexo recognized antigen-specific T cell receptors (TCR) on CD4+ T cells and enhanced Il10 gene transcription in CD4+ T cells. Administration of the OFexo-containing nasal instillation induced antigen-specific type 1 Tregs (Tr1 cells) in the mouse airway tissues. OFexo-induced Tr1 cells showed immune suppressive functions on CD4+ T cell proliferation. Administration of OFexo efficiently alleviated experimental AR in mice. In conclusion, OFexo can induce antigen-specific Tr1 cells that can efficiently alleviate experimental AR. The results suggest that OFexo has the translational potential to be employed for the treatment of AR or other allergic disorders.

Twist1 sustains the apoptosis resistance in eosinophils in nasal mucosa of allergic rhinitis.

Eosinophils (Eos) are the canonical effector cells in allergic rhinitis (AR) and many inflammatory diseases. The mechanism of eosinophilia occurring in the lesion sites is not fully understood yet. Twist1 protein (Twist, in short) is an apoptosis inhibitor that also has immune regulatory functions. This study aims to investigate the role of Twist in the pathogenesis of eosinophilia in AR. In this study, surgically removed human nasal mucosal samples were obtained from patients with chronic sinusitis and nasal polyps with AR (the AR group) or without AR (the nAR group). Eos were isolated from the samples by flow cytometry. We found that abundant Eos were obtained from the surgically removed nasal mucosa tissues of both nAR and AR groups. Significantly higher Ras activation was detected in AR Eos than that in nAR Eos. Ras activation was associated with the apoptosis resistance in AR Eos. The Twist (an apoptosis inhibitor) expression was higher in AR Eos, which was positively correlated with the Ras activation status. The sensitization to IgG induced Twist expression in Eos, in which Ras activated the MAPK-HIF-1α pathway, the latter promoted the Twist gene transcription. Twist bound Rac GTPase activating protein-1 to sustain the Ras activation in Eos. Ras activation sustained the apoptosis resistance in Eos. In conclusion, high Ras activation was detected in the AR nasal mucosal tissue-isolated Eos. IgG-sensitization induced Ras activation and Twist expression in Eos, that conferred Eos the apoptosis resistance.

Specific antigen-guiding exosomes inhibit food allergies by inducing regulatory T cells.

The therapies for food allergy (FA) need to be improved. The generation of inducible regulatory T cells (Tregs) can support immune tolerance in the body. This study aims to suppress experimental FA by inducing Tregs through the employment of modified exosomes (mExosomes). In this study, mExosomes were prepared by incubating dendritic cells with interleukin (IL)-2 and ovalbumin (OVA, used as a specific antigen) in the culture. Exosomes were purified from culture supernatant and used as the mExosomes. A murine FA model was developed to test the effects of mExosomes on the generation of Tregs in the mouse intestinal tissues and inhibiting FA. The results showed that mExosomes, which carried IL-2 and a complex of OVA peptide-major histocompatibility complex class II on the surface of exosomes, bound to OVA-specific CD4+ T cells and induced CD4+ T cells to differentiate into Tregs. In the FA mouse intestinal tissues, we found low IL-2 levels that were positively correlated with the number of Tregs. Depletion of IL-2 in mice prevented the generation of Tregs. The levels of peroxisome proliferator-activated receptor-γ were increased in the FA intestinal tissues with inhibited IL-2 production. Administration of mExosomes induced Tregs in the intestinal tissues and efficiently suppressed FA in mice. We conclude that the mExosomes can suppress FA in mice through inducing Tregs. The data suggest that the mExosomes have translational potential in the treatment of FA and other allergic disorders.

Chimeric specific antigen epitope-carrying dendritic cells induce interleukin-17(+) regulatory T cells to suppress food allergy.

BACKGROUND: The on-purpose-modulated dendritic cells (DCs) have shown charming effects on restoring immune regulatory functions in subjects with immune diseases. OBJECTIVE: This study aims to construct DCs carrying chimerical antigen (Ag) peptides (CAP-DCs) to induce interleukin (IL)-17+ inducible Tregs (iTregs) to alleviate food allergy (FA) in a murine model. METHODS: In this study, we constructed CAP-DCs. The CAP is a fusion protein, consisting of a segment of recombinant scFv of anti-DEC205 antibody and an ovalbumin (OVA) epitope (IC). A murine OVA-FA model was developed to test the effects of CAP-DCs on suppressing the allergic response in the intestine. RESULTS: The CAP-DCs are characterized as that a complex of scFv-IC is presented on the surface of the cells, moderately express CD80 and CD86 as well as IL-6, IL-23, transforming growth factor (TGF)-ß and CCR9. After being passively transferred with CAP-DCs or injection of scFv-IC, Ag-specific IL-17+ Foxp3+ iTregs were induced in the intestinal lamina propria of FA mice. The iTregs showed immune suppressive effects on Ag-specific Th2 response. FA mice were adoptively transferred with the CAP-DCs or scFv-IC injection, which resulted in a significant decrease in the number of Ag-specific Th2 cells and suppression of FA response in an Ag-specific manner. CONCLUSIONS AND CLINICAL RELEVANCE: CAP-DCs can ameliorate FA response by inducing Ag-specific IL-17+ Foxp3+ iTregs and suppressing Ag-specific Th2 response. To generate CAP-DCs has the translational potential in the treatment of FA.

Cold stress promotes IL-33 expression in intestinal epithelial cells to facilitate food allergy development.

BACKGROUND: The causative factors and pathogenesis of food allergy (FA) is not fully understood yet. Cold stress (CS) occurs frequently in human life that influences physiological activities in the body. In this study, we aimed to investigate the chronic CS (CS) effects on promoting the expression of IL-33 in intestinal epithelial cells. METHODS: CS was carried out by placing mice at 4 °C for 1 h daily for 7 consecutive days. We developed a mouse model used to test the effects of CS on the FA development. RESULTS: We found that, similar to conventional FA mouse model, CS induced the core body temperature to drop markedly in mice, increased intestinal epithelial barrier permeability and facilitated FA development. CS promoted interleukin (IL)-33 expression in intestinal epithelial cells through the adrenocorticotropic hormone (ACTH)/cortisol axis and via inducing the Il33 promoter methylation. CS facilitated the FA development in mice, that could be blocked by depletion of IL-33 expression in intestinal epithelial cells. CONCLUSIONS: CS induces IL-33 expression in intestinal epithelial cells to promote Th2 polarization in the intestinal tissues and facilitates FA development.

Exosomes carry IL-10 and antigen/MHC II complexes to induce antigen-specific oral tolerance.

BACKGROUND: It is known that the immune tolerance can be naturally established in the intestine, while the mechanism by which the immune tolerance development in the intestine is not fully understood yet. Vasoactive intestinal peptides (VIP) has the immune regulatory functions. This study aims to investigate the role of VIP in the immune tolerance development in the intestine. METHODS: Intestinal epithelial cell (IEC)-derived exosomes were prepared. The exosomes carried IL-10 and antigen/MHC II complexes. VIP-deficient (VIPd) mice and wild type mice were employed to test the role of VIP in the development of immune tolerance in the intestine. RESULTS: VIPd mice failed to induce type 1 regulatory T cells (Tr1 cells) in the intestine and retarded the establishment of antigen (Ag)-specific immune tolerance. Exposure to VIP in the culture induced IL-10 expression in intestinal epithelial cells (IECs). Exosomes derived from ovalbumin (OVA, used as a specific Ag)/VIP-primed IECs carried IL-10 and OVA/MHC II complexes; these exosomes were designated IL10CARs (IL-10/chimeric antigen receptor-carrying exosomes). IL10CARs could recognize OVA-specific CD4+ T cells and converted OVA-specific CD4± T cells to OVA-specific Tr1 cells. Administration of IL10CARs suppressed experimental food allergy. CONCLUSIONS: The data show that IL10CARs are capable of suppressing experimental FA by inducing antigen-specific Tr1 cells, which has the translation potential for FA treatment.

CARsomes inhibit airway allergic inflammation in mice by inducing antigen-specific Th2 cell apoptosis.

BACKGROUND: Skewed T helper (Th)2 response plays a crucial role in the pathogenesis of allergic diseases. The therapeutic efficacy for allergic diseases is unsatisfactory currently. This study aims to regulate the skewed Th2 response with CARsomes. METHODS: The CARsome consisted of an epitope of Dermatophagoides farina-1 (Derf1), a segment of the anti-DEC205 antibody, the scFv, and an open reading frame of perforin. This fusion protein binds to DEC205 molecule on the surface of exosomes derived from dendritic cells (DC). The effects of CARsome on inducing antigen (Ag)-specific Th2 cell apoptosis were assessed both in vivo and in vitro. RESULTS: Exposure to CARsomes in the culture induced Ag-specific Th2 cell apoptosis. Injection of CARsomes through the vein puncture also induced Ag-specific Th2 cell apoptosis in the lungs of sensitized mice. CARsomes could induce Ag-specific regulatory T cells. Administration of CARsomes efficiently inhibited experimental allergic airway inflammation. CONCLUSIONS: The CARsomes can inhibit allergic airway inflammation by inducing Ag-specific Th2 cell apoptosis and induce Ag-specific regulatory T cells. The data suggest that CARsomes have the translational potential to be used to treat allergic airway inflammation.

Bcl2L12 Contributes to Th2-Biased Inflammation in the Intestinal Mucosa by Regulating CD4+ T Cell Activities.

The Th2-biased inflammation and immune deregulation play a critical role in the pathogenesis of ulcerative colitis (UC). Recent studies indicate that the Bcl2-like protein 12 (Bcl2L12) is associated with immune deregulation of UC. This study aims to investigate the role of Bcl2L12 in the induction of aberrant Th2-biased inflammation. In this study, peripheral blood samples were collected from patients with inflammatory bowel disease. The Th2 cell activities were analyzed by flow cytometry, real-time quantitative RT-PCR, and Western blotting. Mice with Bcl2L12-knockout CD4+ T cells were used in the experiments. The results showed that the expression of Bcl2L12 was detected in peripheral CD4+ T cells, which was significantly higher in UC patients than in healthy subjects. A positive correlation between the expression of Bcl2L12 and Th2 cytokines was detected in CD4+ T cells from UC patients. Naive CD4+ T cells with Bcl2L12 overexpression were prone to differentiate into Th2 cells. Mice with Bcl2L12 deficiency failed to induce the Th2-biased inflammation in the intestine. Bcl2L12 bound GATA3 to form a complex to enhance the binding between GATA3 and the Il4 promoter to enhance the expression of IL-4 in CD4+ T cells. CD4+ T cells with Bcl2L12 overexpression were resistant to apoptosis. In conclusion, the Bcl2L12 is a critical factor in the induction of aberrant Th2 polarization by upregulating Th2 responses and downregulating Th2 cell apoptosis. Bcl2L12 may be a novel therapeutic target in the management of the disorders with Th2-biased inflammation.