Calcitonin Gene-Related peptide receptor antagonist suppresses allergic asthma responses via downregulation of group 2 innate lymphoid cells in mice.

Allergic asthma is caused by chronic inflammation and hyper-responsiveness of the airway and is thought to be mediated by adaptive T helper type 2 (Th2)-driven immunity. However, recent studies have demonstrated that neuropeptide calcitonin gene-related peptide (CGRP)-mediated activation of group 2 innate lymphoid cells (ILC2s) may contribute to the development of asthma pathogenesis. Here, we investigated the therapeutic effects of the systemic administration of rimegepant, a CGRP receptor antagonist, on allergic asthma. Hyperplasia of CGRP-immunoreactive pulmonary neuroendocrine cells (PNECs) was observed in ovalbumin (OVA)-induced asthmatic mice. Concomitant with this, we observed an increase in the content of total lung CGRP. Upon antigen challenge, the concentration of plasma CGRP was transiently upregulated, whereas CGRP immunoreactivity within PNECs was intensively downregulated, suggesting that PNECs were the most likely source of CGRP. When rimegepant was administered according to CGRP kinetics, it suppressed asthma phenotypes, including airway hyper-responsiveness, infiltration of inflammatory cells in bronchoalveolar lavage fluid (BALF), hyperplasia of mucus-producing cells, and production of the Th2 cytokine IL-5. Moreover, we observed a decrease in the number of ILC2s and their capacity for IL-5 release in the presence of IL-33 in rimegepant-treated mice. In the allergic asthma model, rimegepant suppressed the activation of ILC2s mediated by PNEC-derived CGRP and subsequently impaired adaptive Th2-driven immunity, which ameliorated asthmatic phenotypes. Thus, an anti-CGRP signal strategy to target ILC2 will be a novel and attractive approach for treating allergic asthma that is refractory to other treatments.

T cell infiltration into the brain triggers pulmonary dysfunction in murine Cryptococcus-associated IRIS.

Cryptococcus-associated immune reconstitution inflammatory syndrome (C-IRIS) is a condition frequently occurring in immunocompromised patients receiving antiretroviral therapy. C-IRIS patients exhibit many critical symptoms, including pulmonary distress, potentially complicating the progression and recovery from this condition. Here, utilizing our previously established mouse model of unmasking C-IRIS (CnH99 preinfection and adoptive transfer of CD4+ T cells), we demonstrated that pulmonary dysfunction associated with the C-IRIS condition in mice could be attributed to the infiltration of CD4+ T cells into the brain via the CCL8-CCR5 axis, which triggers the nucleus tractus solitarius (NTS) neuronal damage and neuronal disconnection via upregulated ephrin B3 and semaphorin 6B in CD4+ T cells. Our findings provide unique insight into the mechanism behind pulmonary dysfunction in C-IRIS and nominate potential therapeutic targets for treatment.

IL-1ß Derived Th17 Immune Responses Are a Critical Factor for Neutrophilic-Eosinophilic Airway Inflammation on Psychological Stress-Induced Immune Tolerance Breakdown in Mice.

INTRODUCTION: Asthma is an inflammatory reaction mediated by type 2 helper T (Th2) cells and is known to increase eosinophil levels. Our previous study showed that stress-related asthma can cause neutrophilic and eosinophilic airway inflammation by suppressing immune tolerance. However, the mechanism of stress-induced neutrophilic and eosinophilic airway inflammation remains unclear. Therefore, to elucidate the cause of neutrophilic and eosinophilic inflammation, we investigated the immune response during the induction of airway inflammation. In addition, we focused on the relationship between immune response modulation immediately after stress exposure and the development of airway inflammation. METHODS: Asthmatic mice were induced by three phases using female BALB/c mice. During the first phase, the mice were made to inhale ovalbumin (OVA) to induce immune tolerance before sensitization. Some mice were exposed to restraint stress during the induction of immune tolerance. In the second phase, the mice were sensitized with OVA/alum intraperitoneal injections. In the final phase, onset of asthma was induced through OVA exposure. Asthma development was evaluated based on airway inflammation and T-cell differentiation. Microarray and qPCR analyses were used to enumerate candidate factors to investigate the starting point of immunological modification immediately after stress exposure. Furthermore, we focused on interleukin-1ß (IL-1ß), which initiates these immune modifications, and performed experiments using its receptor blocker interleukin-1 receptor antagonist (IL-1RA). RESULTS: Stress exposure during immune tolerance induction increased eosinophil and neutrophil airway infiltration. This inflammation was associated with decreased T regulatory cell levels and increased Th2 and Th17 levels in bronchial lymph node cells. Microarray and qPCR analyses showed that the initiation of Th17 differentiation might be triggered by stress exposure during tolerance induction. IL-1RA administration during stress exposure suppressed neutrophilic and eosinophilic airway inflammation via Th17 reduction and Treg increase. CONCLUSIONS: Our results show that psychological stress causes both eosinophilic and neutrophilic inflammatory responses due to the breakdown of immune tolerance. Furthermore, stress-induced inflammation can be abolished using IL-1RA.

Estrogen receptor alpha signaling in dendritic cells modulates autoimmune disease phenotype in mice.

Estrogen is a disease-modifying factor in multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) via estrogen receptor alpha (ERα). However, the mechanisms by which ERα signaling contributes to changes in disease pathogenesis have not been completely elucidated. Here, we demonstrate that ERα deletion in dendritic cells (DCs) of mice induces severe neurodegeneration in the central nervous system in a mouse EAE model and resistance to interferon beta (IFNß), a first-line MS treatment. Estrogen synthesized by extragonadal sources is crucial for controlling disease phenotypes. Mechanistically, activated ERα directly interacts with TRAF3, a TLR4 downstream signaling molecule, to degrade TRAF3 via ubiquitination, resulting in reduced IRF3 nuclear translocation and transcription of membrane lymphotoxin (mLT) and IFNß components. Diminished ERα signaling in DCs generates neurotoxic effector CD4+ T cells via mLT-lymphotoxin beta receptor (LTßR) signaling. Lymphotoxin beta receptor antagonist abolished EAE disease symptoms in the DC-specific ERα-deficient mice. These findings indicate that estrogen derived from extragonadal sources, such as lymph nodes, controls TRAF3-mediated cytokine production in DCs to modulate the EAE disease phenotype.

The A118G single-nucleotide polymorphism in OPRM1 is a risk factor for asthma severity.

BACKGROUND: Although population studies have implicated emotional burden in asthma severity, the underlying genetic risk factors are not completely understood. We aimed to evaluate the genetic influence of a functional single-nucleotide polymorphism (SNP) in the stress-related µ-opioid receptor gene (OPRM1; A118G SNP, rs1799971) on asthma severity. METHODS: We initially assessed disease severity in asthmatic outpatients carrying A118G. Using an ovalbumin-induced experimental asthma rodent model harboring the functionally equivalent SNP, we investigated the mechanism by which this SNP influences the allergic immune response. RESULTS: Among 292 outpatients, 168 underwent airway hyperresponsiveness (AHR) to methacholine testing. Compared with patients carrying the AA and AG genotypes, those carrying the GG genotype exhibited enhanced AHR. The stress levels were presumed to be moderate among patients and were comparable among genotypes. Compared with Oprm1 AA mice, GG mice demonstrated aggravated asthma-related features and increased pulmonary interleukin-4+CD4+ effector and effector memory T cells under everyday life stress conditions. Intraperitoneal naloxone methiodide injection reduced effector CD4+ T cell elevation associated with increased eosinophil numbers in bronchoalveolar lavage fluid of GG mice to the levels in AA mice, suggesting that elevated Th2 cell generation in the bronchial lymph node (BLN) of GG mice induces enhanced eosinophilic inflammation. CONCLUSIONS: Without forced stress exposure, patients with asthma carrying the OPRM1 GG genotype exhibit enhanced AHR, attributable to enhanced Th2 cell differentiation in the regional lymph node. Further research is necessary to elucidate the role of the OPRM1 A118G genotype in the Th2 cell differentiation pathway in the BLN.

Clinicopathologic Analysis of Primary Adrenal Diffuse Large B-Cell Lymphoma: A Reappraisal of 23 Japanese Patients Based on EBV Association and PD-L1 Expression in Tumor Cells.

Primary adrenal diffuse large B-cell lymphoma (PA-DLBCL) is rare. We investigate 23 Japanese patients with PA-DLBCL to understand the clinicopathologic features and biological behavior of this disease. The 17 males and 6 females had a median age of 74 years (range: 40 to 86 y). Tumor cells harbored Epstein-Barr virus-encoded small RNA (EBER) in 9 (39%) samples, including samples from the 2 patients with methotrexate-associated B-cell lymphoproliferative disorder. Programmed cell death ligand 1 (PD-L1) expression was detected in tumor cells of 6 (26%) samples, including 1 EBER+ and 5 EBER- samples. Four (17%) patients exhibited an intravascular proliferating pattern, and all 4 patient samples showed positive staining for PD-L1 in tumor cells. Among those patients, 3 showed intravascular proliferating pattern accompanied by a diffuse extravascular proliferation of tumor cells, and 1 patient was diagnosed with intravascular large B-cell lymphoma. We divided the 23 patients into 3 groups: EBER+ (n=9, 39%), EBER-PD-L1+ (n=5, 22%), and EBER-PD-L1- (n=9, 39%). A comparison of the outcomes among the 3 groups showed significant differences in overall survival (P=0.034). The EBER+ group had the worst prognosis, and the EBER-PD-L1- group had the best prognosis. We also compared the outcomes among the 3 groups that received rituximab-containing chemotherapies. Both the overall survival and progression-free survival were significantly different among these groups (P<0.001 and P=0.002, respectively). In conclusion, we evaluated 3 types of PA-DLBCL and found that each had unique clinical, pathologic, and prognostic features. Our results suggested that immune senescence, iatrogenic immunodeficiency, and immune evasion contribute to the development of PA-DLBCL.

Altered Immune Regulation of Dendritic Cells and Enhanced Cytokine Production of T Cells in the Pathogenesis of Eosinophilic Chronic Rhinosinusitis.

INTRODUCTION: Eosinophilic chronic rhinosinusitis (ECRS) is a refractory chronic disease defined by recurrent nasal polyps with severe eosinophilic infiltration. This is mainly due to enhanced type 2-dominant immune responses, but the underlying mechanism is still not fully understood. OBJECTIVE AND METHODS: In the present study, we aimed to determine the characteristics of dendritic cells (DCs) and cytokine profiles of T cells in the peripheral blood of individuals with ECRS and age- and sex-matched healthy controls (HC). RESULTS AND CONCLUSION: The ratios of myeloid (m)DC1s to DCs and PD-L1+ mDC1s to mDC1s were higher in ECRS patients than in HC. The proportions of plasmacytoid (p)DCs in DCs, and human leukocyte antigen-DR+ pDCs and ILT3+ pDCs in pDCs were lower in ECRS patients than in HC. In a characterization of T cells, IL-4+CD4+, IFN-γ+CD4+, IL-4+IFN-γ+CD4+, IL-4+Foxp3+CD4+, IFN-γ+Foxp3+CD4+, IFN-γ+IL-4-Foxp3-CD4+, IL-4+CD8+, IL-4+IFN-γ+CD8+, and IL-4+Foxp3+CD8+ T-cell populations were significantly higher in ECRS patients than in HC. These results suggest that the enhanced immune regulation of mDC1, diminished capacity of pDCs, and increased proportion of the T-cell phenotypes in peripheral blood might be factors in ECRS pathogenesis.

Expression of programmed cell death ligand-1 by immune cells in the microenvironment is a favorable prognostic factor for primary diffuse large B-cell lymphoma of the central nervous system.

Primary diffuse large B-cell lymphoma (DLBCL) of the central nervous system (PCNS-DLBCL) is rare. Thirty-nine patients consecutively diagnosed as having PCNS-DLBCL were analyzed to highlight the prognostic value of the expression of programmed cell death ligand-1 (PD-L1) by neoplastic cells and immune cells in the microenvironment. They were positive for CD20 in all (100%), CD5 in two (5%), CD10 in nine (23%), BCL-2 in 27 (69%), BCL-6 in 34 (87%), and MUM-1 in 37 (95%). Only one case was positive for neoplastic PD-L1, with an unexpectedly long clinical course of 92 months. The remaining 38 cases were further divided into three groups based on the percentage of PD-L1+ cells among microenvironmental immune cells. Cutoffs of < 5%, 5-40%, and ≥ 40% successfully stratified mean prognoses with three-year overall survival (OS) of 21%, 63%, and 100% (P = 0.009), respectively. Progression-free survival (PFS) and OS were different between the groups with and without methotrexate (MTX)-containing chemotherapy (P = 0.007 and P < 0.001, respectively). Multivariate analysis identified three independent adverse factors of OS: PD-L1 negativity (< 5%) on microenvironmental immune cells (P = 0.027), deep structure involvement (P = 0.034), and performance status (PS) 2-4 (P = 0.009). The study showed that PD-L1 expression on immune cells in the microenvironment was associated with prognosis among patients with PCNS-DLBCL.

Novel Toll-Like Receptor 9 Agonist Derived from Cryptococcus neoformans Attenuates Allergic Inflammation Leading to Asthma Onset in Mice.

INTRODUCTION: The enhanced type 2 helper (Th2) immune response is responsible for the pathogenesis of allergic asthma. To suppress the enhanced Th2 immune response, activation of the Th1 immune response has been an alternative strategy for anti-asthma therapy. In this context, effective Th1-inducing adjuvants that inhibit the development of allergic asthma but do not flare the side effects of the primary agent are required in clinical treatment and preventive medicine. OBJECTIVE: In this study, we aimed to determine the regulation of the Th2 type immune response in asthma by a novel immunostimulatory oligodeoxynucleotide (ODN) derived from Cryptococcus neoformans, termed ODN112, which contains a cytosine-guanine (CG) sequence but not canonical CpG motifs. METHODS: Using an ovalbumin-induced asthma mouse model, we assessed the effect of ODN112 on prototypical asthma-related features in the lung and on the Th1/Th2 profile in the lymph nodes and lung of mice treated with ODN112 during sensitization. RESULTS AND CONCLUSION: ODN112 treatment attenuated asthma features in mice. In the bronchial lymph nodes of the lungs and in the spleen, ODN112 increased interferon-γ production and attenuated Th2 recall responses. In dendritic cells (DCs) after allergen sensitization, ODN112 enhanced cluster of differentiation (CD) 40 and CD80 expression but did not alter CD86 expression. Interleukin-12p40 production from DCs was also increased in a Th2-polarizing condition. Our results suggest that ODN112 is a potential Th1-inducing adjuvant during Th2 cell differentiation in the sensitization phase.

Maternal Separation as Early-Life Stress Causes Enhanced Allergic Airway Responses by Inhibiting Respiratory Tolerance in Mice.

Epidemiologic studies indicate that exposure to psychosocial stress in early childhood is a risk factor of adult-onset asthma, but the mechanisms of this relationship are poorly understood. Therefore, we examined whether early-life stress increases susceptibility to adult-onset asthma by inhibiting the development of respiratory tolerance. Neonatal BALB/c female mice were aerosolized with ovalbumin (OVA) to induce immune tolerance prior to immune sensitization with an intraperitoneal injection of OVA and the adjuvant aluminum hydroxide. Maternal separation (MS) was applied as an early-life stressor during the induction phase of immune tolerance. The mice were challenged with OVA aerosol in adulthood, and allergic airway responses were evaluated, including airway hyper-responsiveness to inhaled methacholine, inflammatory cell infiltration, bronchoalveolar lavage fluid levels of interleukin (IL)-4, IL-5, and IL-13, and serum OVA-specific IgE. We then evaluated the effects of MS on the development of regulatory T (Treg) cells in bronchial lymph nodes (BLN) and on splenocyte proliferation and cytokine expression. In mice that underwent MS and OVA tolerization, the allergic airway responses and OVA-induced proliferation and IL-4 expression of splenocytes were significantly enhanced. Furthermore, exposure to MS was associated with a lower number of Treg cells in the BLN. These findings suggest that exposure to early-life stress prevents the acquisition of respiratory tolerance to inhaled antigen due to insufficient Treg cell development, resulting in Th2-biased sensitization and asthma onset. We provide the evidence for inhibitory effects of early-life stress on immune tolerance. The present findings may help to clarify the pathogenesis of adult-onset asthma.

Increased Susceptibility to Allergic Asthma with the Impairment of Respiratory Tolerance Caused by Psychological Stress.

BACKGROUND: Bronchial asthma is characterized by type 2 T helper (Th2) cell inflammation, essentially due to a breakdown of immune tolerance to harmless environmental allergens. Etiologically, experiences of psychological stress can be associated with a heightened prevalence of asthma. However, the mechanisms underlying stress-related asthma development are unclear. In this study, we examined whether psychological stress increases susceptibility to allergic asthma by downregulating immune tolerance. METHODS: Female BALB/c mice were sensitized with ovalbumin/alum, followed by ovalbumin inhalation. Ovalbumin inhalation induced immune tolerance before sensitization occurred. Some mice were exposed to restraint stress during tolerance induction or sensitization. Asthma development was evaluated by airway responsiveness, inflammation, cytokine expression, and IgE synthesis. Sensitization was evaluated by measuring proliferation and cytokine production by splenocytes. The effects of stress exposure on the numbers and functions of dendritic cells and regulatory T (Treg) cells in bronchial lymph nodes and spleens were evaluated. To investigate the role of endogenous glucocorticoid in inhibiting immune tolerance after stress exposure, we examined the effects of (i) a glucocorticoid-receptor antagonist administered prior to stress exposure, and (ii) exogenous gluco-corticoid (instead of stress exposure). RESULTS: Asthmatic responses and Th2-biased sensitization, which were suppressed in tolerized mice, re-emerged in tolerized mice stressed during tolerance induction in association with decreased tolerogenic dendritic and Treg cell numbers. The effects of stress exposure on tolerized mice were abolished by administering a glucocorticoid-receptor antagonist and reproduced by administering exogenous glucocorticoid without stress. CONCLUSIONS: Our findings suggested that psychological stress can potentially increase allergic asthma susceptibility by inhibiting immune tolerance.

The expression of 11 beta hydroxysteroid dehydrogenase in severe allergic rhinitis.

OBJECTIVE: To clarify the roles of 11 beta-HSD in resistance to glucocorticoid therapy for allergic rhinitis, a case series study was conducted. METHODS: The patient group consisted of 20 subjects with allergic rhinitis, aged from 21 to 46 years (mean age 26.5), who showed persistent GC resistance necessitating surgical removal of the inferior turbinate after 6 months' GC treatment. The patients with poor response to GC treatment for 6 months' were defined as GC resistance. The control group consisted of 10 subjects aged from 16 to 39 years (mean age 24.5) who underwent maxillofacial surgery, from whom nasal tissues were taken and who did not receive GC treatment. Nasal mucosal tissues from patients and cntorol subjects were examined immunohistochemically. The sections were washed with 0.01 M phosphate-buffered saline (PBS; pH 7.2) containing 0.15 M NaCl and 0.01% Triton X-100, and incubated for 2 h with rabbit polyclonal anti-11 beta HSD1 and 11 beta-HSD2 antibody (Santa Cruz Biotechnology, Inc., Santa Cruz, CA, USA), each diluted 1:200 in PBS containing 0.1% bovine serum albumin. Immunostained sections were assessed under an Olympus microscope with an eyepiece reticule at 200 X magnification. Cell counts are expressed as means per high-power field (0.202 mm2). Control group means (arithmetic mean ± SD) were compared with patient group means by Mann-Whitney U-test at P = 0.05. RESULTS: Although 11 beta-HSD1 was expressed to a similar extent in patients and controls, 11 beta-HSD2 was expressed significantly more in patients with severe allergic rhinitis, resulting in a increased HSD-1/HSD-2 ratio. The significantly increased expression of 11 beta-HSD2 in the nasal epithelium and submucosal inflammatory cells of patients with severe nasal allergy were observed in the present study. CONCLUSION: Our findings suggest that 11 beta-HSD2 plays an important role in resistance to glucocorticoid therapy for allergic rhinitis, and its expression might be used as an additional parameter indicating steroid resistance in allergic rhinitis.

Catfish rhamnose-binding lectin induces G0/1 cell cycle arrest in Burkitt's lymphoma cells via membrane surface Gb3.

Silurus asotus egg lectin (SAL), an α-galactoside-binding protein isolated from the eggs of catfish, is a member of the rhamnose-binding lectin family that binds to Gb3 glycan (Galα1-4Galß1-4Glc). We have previously demonstrated that SAL reduces the proliferation of Gb3-expressing Burkitt's lymphoma Raji cells and confirm here that it does not reduce their viability, indicating that unlike other lectins, it is not cytotoxic. The aim of this study was to determine the signal transduction mechanism(s) underlying this novel SAL/Gb3 binding-mediated effect profile. SAL/Gb3 interaction arrested the cell cycle through increasing the G0/1 phase population of Raji cells. SAL suppressed the transcription of cell cycle-related factors such as c-MYC, cyclin D3, and cyclin-dependent protein kinase (CDK)-4. Conversely, the CDK inhibitors p21 and p27 were elevated by treatment with SAL. In particular, the production of p27 in response to SAL treatment increased steadily, whereas p21 production was maximal at 12 h and lower at 24 h. Activation of Ras-MEK-ERK pathway led to an increase in expression of p21. Notably, treatment of Raji cells with anti-Gb3 mAb alone did not produce the above effects. Taken together, our findings suggest that Gb3 on the Raji cell surface interacts with SAL to trigger sequential GDP-Ras phosphorylation, Ras-MEK-ERK pathway activation, p21 production, and cell cycle arrest at the G0/1 phase.

The involvement of central nervous system histamine receptors in psychological stress-induced exacerbation of allergic airway inflammation in mice.

BACKGROUND: Psychological stress is one of the major risk factors for asthma exacerbation. Although histamine in the brain acts as an excitatory and inhibitory neurotransmitter associated with psychological stress, the contribution of brain histamine to psychological stress-induced exacerbation of asthma remains unclear. The objective of this study was to investigate the role of histamine receptors in the CNS on stress induced asthma aggravation. METHODS: We monitored the numbers of inflammatory cells and interleukin (IL)-13 levels in bronchoalveolar lavage fluid, airway responsiveness to inhaled methacholine, mucus secretion in airway epithelial cells, and antigen-specific IgE contents in sera in a murine model of stress-induced asthma treated with epinastine (an H1R antagonist), thioperamide (an H3/4R antagonist), or solvent. RESULTS: All indicators of stress-induced asthma exacerbation were significantly reduced in stressed mice treated with epinastine compared with those treated with solvent, whereas treatment with thioperamide did not reduce the numbers of inflammatory cells in the stressed mice. CONCLUSIONS: These results suggest that H1R, but not H3/4R, may be involved in stress-induced asthma exacerbations in the central nervous system.

CD8+ T Cells Mediate Female-Dominant IL-4 Production and Airway Inflammation in Allergic Asthma.

The prevalence and severity of bronchial asthma are higher in females than in males after puberty. Although antigen-specific CD8+ T cells play an important role in the development of asthma through their suppressive effect on cytokine production, the contribution of CD8+ T cells to sex differences in asthmatic responses remains unclear. In the present study, we investigated the sex-specific effect of CD8+ T cells in the suppression of asthma using an ovalbumin mouse model of asthma. The number of inflammatory cells in bronchoalveolar lavage (BAL) fluid, lung type 2 T-helper cytokine levels, and interleukin-4 (IL-4) production by bronchial lymph node cells were significantly higher in female wild-type (WT) mice compared with male mice, whereas no such sex differences were observed between male and female cd8α-disrupted mice. The adaptive transfer of male, but not female, CD8+ T cells reduced the number of inflammatory cells in the recovered BAL fluid of male recipient mice, while no such sex difference in the suppressive activity of CD8+ T cells was observed in female recipient mice. Male CD8+ T cells produced higher levels of IFN-γ than female CD8+ T cells did, and this trend was associated with reduced IL-4 production by male, but not female, CD4+ T cells. Interestingly, IFN-γ receptor expression on CD4+ T cells was significantly lower in female mice than in male mice. These results suggest that female-dominant asthmatic responses are orchestrated by the reduced production of IFN-γ by CD8+ T cells and the lower expression of IFN-γ receptor on CD4+ T cells in females compared with males.

Contribution of CD4+ T cells and dendritic cells to female-dominant antigen-induced T helper type 2 cytokine production by bronchial lymph node cells.

BACKGROUND: After puberty, asthma severity is higher in women than in men. The underlying mechanisms of this gender difference are not fully understood. In murine models of allergic asthma, more severe airway inflammation in female mice is associated with higher levels of T helper type 2 (Th2) cytokines. The aim of this study was to investigate the contributions of CD4(+) T cells and dendritic cells (DCs) to the differences in Th2 cytokine production between sexes. METHODS: Bronchial lymph node (BLN) cells from ovalbumin (OVA)-sensitized male and female C57BL/6 mice were stimulated with OVA and anti-CD3/CD28 antibodies. The CD4(+) T cells and DCs purified from BLN cells were cocultured with OVA in a sex-matched or mismatched fashion. The CD4(+) T cells were also stimulated with anti-CD3/CD28 antibodies. The concentrations of interleukin (IL)-5, IL-4, IL-13 and interferon (IFN)-γ in the culture supernatants were measured. RESULTS: The concentrations of IL-5, IL-4 and IL-13, but not IFN-γ, were significantly higher in female BLN cells stimulated with OVA than in male BLN cells. Sex differences were also observed in the CD4(+) T cells stimulated with anti-CD3/CD28 antibodies, whereas only IL-4 was significantly different in the BLN cells stimulated with antibodies. IL-5 production by OVA-stimulated male and female CD4(+) T cells, but not IL-4 or IL-13 production, was significantly increased in the coculture with female DCs when compared to the male DCs. CONCLUSIONS: The differences in Th2 cytokine production between sexes by the BLN cells may be attributable, at least in part, to the differing functions of CD4(+) T cells and DCs between sexes.

Higher sensitivity of male CD4+ T cells to suppressive effects of CD8+ T cells on IL-5 production compared to female CD4+ T cells.

BACKGROUND: Asthma prevalence and severity are higher in females than in males after puberty. The underlying mechanisms of this gender difference are not fully understood. More severe airway inflammation in female mice has been reported to be associated with higher levels of T helper type 2 (Th2) cytokines in asthma models. The aim of this study was to investigate sex differences in CD4+ and CD8+ T cell functions in Th2 cytokine production. METHODS: Splenocytes from naive mice were stimulated with anti-CD3/CD28 antibodies and the proportions of CD4+ and CD8+ T cells were analyzed. CD4+ T cells were stimulated in the presence of CD8+ T cells. The concentrations of interleukin (IL)-5, IL-10 and interferon (IFN)-γ in the cultures were measured. RESULTS: The concentration of IL-5, but not IFN-γ, was significantly higher in female splenocytes than in male splenocytes. There were no sex differences in the proportions of CD4+ and CD8+ T cells in the splenocytes. Although the IL-5 production levels in male and female CD4+ T cells were similar, IL-5 production in male CD4+ T cells, but not female CD4+ T cells, was suppressed by both male and female CD8+ T cells. While IL-5 and IL-10 were not detected in the cultures from both male and female CD8+ T cells, IFN-γ concentration in female CD8+ T cells was significantly higher than in male CD8+ T cells. CONCLUSIONS: The sex difference in the sensitivity of CD4+ T cells to CD8+ T cell suppression might contribute to the sex difference in IL-5 production by splenocytes.

MRP1 expressed on Burkitt's lymphoma cells was depleted by catfish egg lectin through Gb3-glycosphingolipid and enhanced cytotoxic effect of drugs.

A novel anticancer mechanism of catfish (Silurus asotus) egg lectin (SAL) was found to occur via the down-regulation of the membrane transopter protein, MRP1 (multidrug resistance associate protein-1) on Burkitt's lymphoma cells through Gb3(Galα1-4Galß1-4Glc)-glycosphingolipid. Although SAL did not influence the viability of the cells directly, only 10 and 100 ng/mL of vincristine and etoposide, respectively induced anticancer effects when the lectin was applied in conjunction with these drugs. These phenomena were specifically inhibited by the co-presence of the α-galactoside, melibiose, which is a strong haptenic sugar of SAL that mimicks Gb3. The degree of expression regulation of the transporter proteins on the cells surface was investigated through the examination of the binding between SAL and Gb3-glycosphingolipid by immunological and molecular biological procedures. PCR data showed that MRP1 was more highly expressed when compared to another ATP-binding cassette family, multi-drug resistant protein and the expression levels of MRP1 on the cells were specifically dose- and time-dependently depleted by the addition of SAL. These results were also evaluated by immunological procedures using FACS and western-blotting. Small interfering RNA coding a part of MRP1 was transfected to Raji cells to knock down the protein, and cell death was increased by 10% when vincristine was administered at a concentration as low as 10 ng/mL compared to non-transfected cells. These results indicated that SAL possesses the potential to enhance the anticancer activites of low-concentrations of vincristine by the down-regulating the MRP1 gene expression to inhibit the multidrug resistance by binding to the target ligand Gb3-glycosphingolipid on Burkitt's lymphoma cells.

T cell subsets related with a sex difference in IL-5 production.

BACKGROUND: Before puberty, the prevalence and severity of asthma are higher in boys than in girls, but this pattern is reversed after puberty. The underlying mechanisms of these gender differences in asthma are not fully understood. Using murine models of allergic asthma, a sex difference in Th2 cytokine production has been suggested to contribute to the gender differences in asthma. Therefore, we determined which subsets of T cells are involved in the sex difference in Th2 cytokine production. METHODS: Splenocytes from wild-type mice and CD4+ T cell-, CD8+ T cell-, and iNKT cell-deficient mice were stimulated with anti-CD3/CD28 antibodies for 3 days, and the concentrations of IL-4, IL-5, IL-13, and IFN-γ in the cultures were measured by ELISA. RESULTS: IL-5, but not IL-4 and IL-13, concentrations in culture derived from female wild-type mice were significantly higher than those in male wild-type mice. The sex difference in IL-5 concentrations was not observed in the cultures of splenocytes from CD4+ and CD8+ T cell-deficient mice. The disappearance of the sex differences in CD4+ and CD8+ T cell-deficient mice was attributable to a decrease in IL-5 concentration in female mice and an increase in IL-5 concentration in male mice. In iNKT cell-deficient mice, the sex difference was still observed. There was no significant difference between the sexes in any type of mice with respect to IFN-γ production. CONCLUSIONS: There was a sex difference in IL-5 production by splenocytes stimulated by TCR activation. The difference might be attributable to sex differences in CD4+ and CD8+ T cell functions.