anti-TSLP Antibody Research Articles

Development of a novel humanized anti-TSLP monoclonal antibody, QX008N, and exploration of combination therapy of anti-TSLP antibody and anti-IL-4R antibody

BackgroundSevere asthma is a complex and chronic respiratory disease, and current conventional treatments are not effective in controlling the patients’ condition. Thymic stromal lymphopoietin (TSLP) is a key regulatory factor in the initiation and maintenance of asthma. Thus, blocking TSLP during allergic inflammation emerges as a promising therapeutic approach; however, novel anti-TSLP therapies remain to be developed. Furthermore, the importance of other signaling molecules, such as IL-4 and IL-13, should be considered. Moreover, to the best of our knowledge, the inhibitory effect of binding upstream and downstream signaling molecules has not been assessed. PurposeThis study aimed to develop a novel, humanized anti-TSLP antibody and explore the enhancement in its efficacy when combined with anti-IL-4R antibodies to treat asthma. ResultsQX008N, derived from a rabbit antibody platform, exhibits a high affinity for TSLP and superior efficacy in blocking TSLP-induced signaling pathways and inflammation in vitro compared with Tezepelumab. In a cynomolgus monkey asthma model, QX008N ameliorated lung function and reduced the levels of eosinophils and IgE. Moreover, the coadministration of QX008N with anti-IL-4R antibodies enhanced the inhibition of inflammatory mediator production triggered via costimulation in vitro. In mouse asthma models, the simultaneous blockade of TSLP and IL-4R using anti-TL4R and anti-TSLP surrogates surpassed the efficacy of monotherapy. To the best of our knowledge, the therapeutic effect of a combination of anti-TSLP and IL-4R antibodies in an asthma model has not yet been reported. ConclusionThese results furnish comprehensive preclinical evidence for QX008N as an innovative anti-TSLP therapeutic agent and provide a preliminary rationale for the development of combination therapies that simultaneously target the TSLP and IL-4R signaling pathways.

TRPV4-β-catenin axis is a novel therapeutic target for dry skin-induced chronic itch

Dry skin induced chronic pruritus is an increasingly common and debilitating problem, especially in the elderly. Although keratinocytes play important roles in innate and adaptive immunity and keratinocyte proliferation is a key feature of dry skin induced chronic pruritus, the exact contribution of keratinocytes to the pathogenesis of dry skin induced chronic pruritus is poorly understood. In this study, we generated the acetone-ether-water induced dry skin model in mice and found that epidermal hyperplasia induced by this model is partly dependent on the β-catenin signaling pathway. XAV939, an antagonist of β-catenin signaling pathway, inhibited epidermal hyperplasia in dry skin model mice. Importantly, dry skin induced chronic pruritus also dramatically reduced in XAV939 treated mice. Moreover, acetone-ether-water treatment-induced epidermal hyperplasia and chronic itch were decreased in Trpv4−/− mice. In vitro, XAV939 inhibited hypo-osmotic stress induced proliferation of HaCaT cells, and hypo-osmotic stress induced proliferation of in HaCaT cells and primary cultured keratinocytes were also significantly reduced by blocking TRPV4 function. Finally, thymic stromal lymphopoietin release was examined both in vivo and in vitro, which was significantly inhibited by XAV939 treatment and Trpv4 deficiency, and anti-TSLP antibody treatment significantly decreased AEW-induced scratching behavior. Overall, our study revealed a unique ability of TRPV4 expressing keratinocytes in the skin, which critically mediated dry skin induced epidermal hyperplasia and chronic pruritus, thus provided novel insights into the development of therapies for chronic pruritus in the elderly.

Phase 1 Safety and Pharmacokinetics Study of TAVO101, an Anti-Human Thymic Stromal Lymphopoietin Antibody for the Treatment of Allergic Inflammatory Conditions.

TAVO101 is a humanized anti-human thymic stromal lymphopoietin (TSLP) monoclonal antibody under clinical development for the treatment of atopic dermatitis (AD) and other allergic inflammatory conditions. The crystallizable fragment region of the antibody was engineered for half-life extension and attenuated effector functions. This Phase 1, double-blinded, randomized, placebo-controlled study assessed the safety, tolerability, pharmacokinetics, and immunogenicity of TAVO101 in healthy adult subjects in seven ascending dose cohorts. Subjects received a single intravenous administration of TAVO101 or placebo with a 195-day follow-up. TAVO101 was safe and well tolerated. The incidences and severities of treatment-emergent adverse events were mostly mild and comparable between the active and placebo groups, with no trends of dose relationship. There were no severe adverse events, deaths, or treatment-related withdrawals. TAVO101 exhibited a linear pharmacokinetic profile, low clearance, and a median elimination half-life of 67 days in healthy subjects. All TAVO101-treated subjects tested negative for anti-drug antibodies. To support development in AD, TAVO101 was studied in an oxazolone-induced AD model in hTSLP transgenic mice and demonstrated efficacy. This long-acting anti-TSLP antibody has the potential for stronger and sustained allergic inflammatory disease control. The results from this study warranted further clinical development of TAVO101 in patients.

Exploring the therapeutic potential of monoclonal antibodies targeting TSLP and IgE in asthma management.

In recent years, there has been a growing interest in the utilization of biologic therapies for the management of asthma. Both TSLP and IgE are important immune molecules in the development of asthma, and they are involved in the occurrence and regulation of inflammatory response. A comprehensive search of PubMed and Web of Science was conducted to gather information on anti-TSLP antibody and anti-IgE antibody. This investigation elucidates the distinct mechanistic roles of Thymic Stromal Lymphopoietin (TSLP) and Immunoglobulin E (IgE) in the pathogenesis of asthma, with a particular emphasis on delineating the therapeutic mechanisms and pharmacological properties of monoclonal antibodies targeting IgE and TSLP. Through a meticulous examination of clinical trials involving paradigmatic agents such as omalizumab and tezepelumab, we offer valuable insights into the potential treatment modalities for diseases with shared immunopathogenic pathways involving IgE and TSLP. The overarching objective of this comprehensive study is to delve into the latest advancements in asthma therapeutics and to provide guidance for future investigations in this domain.

Development of a novel humanized anti-TSLP monoclonal antibody HZ-1127 with anti-allergic diseases and cancer potential.

Thymic stromal lymphopoietin (TSLP) is a member of the IL-2 cytokine family and has been widely recognized as a master regulator of type 2 inflammatory responses at barrier surfaces. Recent studies found dysregulation of the TSLP-TSLP receptor (TSLPR) pathway is associated with the pathogenesis of not only allergic diseases but also a wide variety of cancers including both solid tumors and hematological tumors. Thus, the blockade of TSLP represents an attractive therapeutic strategy for allergic diseases and cancer. In this study, we report the development of a novel humanized anti-TSLP monoclonal antibody (mAb) HZ-1127. Binding affinity, specificity, and ability of HZ-1127 in inhibiting TSLP were tested. HZ-1127 selectively binds to the TSLP cytokine with high affinity and specificity. Furthermore, HZ-1127 dramatically inhibits TSLP-dependent STAT5 activation and is more potent than Tezepelumab, which is an FDA-approved humanized mAb against TSLP for severe asthma treatment in inhibiting TSLP-induced CCL17 and CCL22 chemokines secretion in human peripheral blood mononuclear cells. Our pre-clinical study demonstrates that HZ-1127 may serve as a potential therapeutic agent for allergic diseases and cancer.

The last step to achieve barrier damage control.

Heterogeneity characterises inflammatory diseases and different phenotypes and endotypes have been identified. Both innate and adaptive immunity contribute to the immunopathological mechanism of these diseases and barrier damage plays a prominent role triggering type 2 inflammation through the alarmins system, such as anti-Thymic Stromal Lymphopoietin (TSLP). Treatment with anti-TSLP monoclonal antibodies showed efficacy in severe asthma and clinical trials for other eosinophilic diseases are ongoing. The aim of this perspective review is to analyse current advances and future applications of TSLP inhibition to control barrier damage.

Anti-thymic stromal lymphopoietin monoclonal antibody in patients with chronic rhinosinusitis with nasal polyps (DUBHE): Rationale and design of a multicenter, randomized, double-blind, placebo-controlled study.

Chronic rhinosinusitis with nasal polyps (CRSwNP) has a complex pathogenesis and is difficult to treat, which brings a huge economic burden to society. Despite all the progress in the treatment of CRSwNP, some patients with CRSwNP still experience recurrence. Therefore, there is an urgent need to develop novel drugs and treatments for CRSwNP. Thymic stromal lymphopoietin (TSLP) is produced by epithelial cells and mediates type 2 and nontype 2 inflammation through various downstream cellular immune and inflammatory pathways. Anti-TSLP treatment with tezepelumab has been proven to be effective in treating patients with uncontrolled asthma, regardless of their peripheral blood eosinophil levels being low or high. However, there is no relevant research on the usage of anti-TSLP monoclonal antibodies for the treatment of uncontrolled CRSwNP. This is the first phase Ib/IIa study for subjects with uncontrolled CRSwNP, aiming to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, immunogenicity, and preliminary efficacy of multiple ascending doses (MAD) of anti-TSLP monoclonal antibody. The DUBHE is a multicenter, randomized, double-blind, placebo-controlled, phase Ib/IIa clinical study. The study will be composed of 3 periods: a screening/run-in period of 4 weeks, a treatment period of 52 weeks (16 weeks of double-blind treatment period +36 weeks of open-label treatment period), and a safety follow-up period of 12 weeks. No more than 113 subjects with uncontrolled CRSwNP will be divided into 4 groups to receive different doses of CM326 or placebo treatments (55 mg every two weeks [Q2W] group, 110 mg Q2W group, 220 mg Q2W group, and 220 mg every four weeks [Q4W] group). Enrolled patients will be stratified by tissue eosinophil count (TEC). The safety of the monoclonal antibody that targets TSLP in uncontrolled CRSwNP and its preliminary efficacy at 16 weeks of treatment. In this study, for the first time, the safety and preliminary efficacy of MAD of CM326 will be verified. The efficacy of CM326 in patients with eosinophilic CRSwNP (TEC ≥55/high power field [HPF]), as well as noneosinophilic CRSwNP (TEC <55/HPF) will be testified. NCT05324137.

Thymic stromal lymphopoietin contributes to ozone-induced exacerbations of eosinophilic airway inflammation via granulocyte colony-stimulating factor in mice

BackgroundOzone is one of the triggers of asthma, but its impact on the pathophysiology of asthma, such as via airway inflammation and airway hyperresponsiveness (AHR), is not fully understood. Thymic stromal lymphopoietin (TSLP) is increasingly seen as a crucial molecule associated with asthma severity, such as corticosteroid resistance. MethodsFemale BALB/c mice sensitized and challenged with house dust mite (HDM) were exposed to ozone at 2 ppm for 3 h. Airway inflammation was assessed by the presence of inflammatory cells in bronchoalveolar lavage fluid and concentrations of cytokines including TSLP in lung. Anti-TSLP antibody was administered to mice to block the signal. Survival and adhesion of bone marrow-derived eosinophils in response to granulocyte colony-stimulating factor (G-CSF) were evaluated. ResultsOzone exposure increased eosinophilic airway inflammation and AHR in mice sensitized and challenged with HDM. In addition, TSLP, but not IL-33 and IL-25, was increased in lung by ozone exposure. To confirm whether TSLP signaling is associated with airway responses to ozone, an anti-TSLP antibody was administered, and it significantly attenuated eosinophilic airway inflammation, but not AHR. Interestingly, G-CSF, but not type 2 cytokines such as IL-4, IL-5, and IL-13, was regulated by TSLP signaling associated with eosinophilic airway inflammation, and G-CSF prolonged survival and activated eosinophil adhesion. ConclusionsThe present data show that TSLP contributes to ozone-induced exacerbations of eosinophilic airway inflammation and provide greater understanding of ozone-induced severity mechanisms in the pathophysiology of asthma related to TSLP and G-CSF.

Antibody targeting TSLP suppresses DSS-induced colitis and activation of the JAK2/STAT5 pathway in mice.

There is currently no safe or effective treatment for inflammatory bowel disease (IBD), which is defined as recurrent and persistent intestinal inflammation. Thymic stromal lymphopoietin (TSLP) has been shown to be associated with the pathogenesis of IBD, and the JAK2/STAT5 signalling pathway has demonstrated much promise as a novel therapeutic target for IBD. In this study, we first evaluated levels of TSLP in dextran sodium sulphate (DSS)-induced IBD mice. Second, we applied tezepelumab, an anti-TSLP monoclonal antibody (20μg per mouse, intraperitoneally), to DSS-induced IBD mice and quantified the signs of histopathological change, intestinal inflammation, and integrity of the mucosal barrier. In addition, the effect of DSS and/or tezepelumab on the phosphorylation of the JAK/STAT pathway was investigated. TSLP expression levels were elevated in DSS-induced IBD mice, whereas TSLP antibody treatment suppressed the pathological features associated with IBD and alleviated intestinal inflammation and mucosal barrier disruption. Moreover, level of phosphorylated JAK2/STAT5 were increased in DSS-induced IBD mice, but were strongly decreased in the presence of tezepelumab. Our findings suggest that targeting TSLP via the JAK2/STAT5 signalling pathway may be an effective approach for the treatment of IBD.

Chronic spontaneous urticaria—status quo and future

AbstractChronic spontaneous urticaria (CsU) is a chronic inflammatory dermatosis whose etiology is not yet fully understood. In affected patients, it is often associated with a high limitation of health-related quality of life, which necessitates effective therapeutic management. Different immune cell populations such as mast cells, eosinophilic and basophilic granulocytes, and T cells are involved in the pathogenesis of CsU, whereby mast cells playing a key role. In addition, type I autoallergic reactions with auto IgE antibodies or type IIb autoimmune reactions with auto IgG antibodies have been identified in a proportion of patients. The current international guideline initially recommends the use of second-generation H1 antihistamines, first in standard, then in off-label quadruple dosing. Subsequently, the anti-IgE antibody omalizumab should be added. However, this therapy algorithm does not lead to freedom from manifestations in all patients. Therefore, various targeted therapies are currently being evaluated for their efficacy in CsU, such as off-label use of the anti-interleukin receptor alpha (IL4Rα) antibody dupilumab, the anti-IL-17A antibody secukinumab, or interleukin‑5 blockade using mepolizumab, reslizumab, or benralizumab. In addition, new promising compounds such as the Bruton tyrosine kinase (BTK) inhibitors remibrutinib and fenebrutinib, the anti-cKIT antibody barzolvolimab, the anti-SIGLEC8 antibody lirentelimab, the anti-TSLP antibody tezepelumab, the anti-C5aR1 antibody advoralimab, or the topical application of Syk kinase inhibitors are being tested, which were developed according to new insights into the pathogenesis of CsU. The BTK inhibitor fenebrutinib is currently not being pursued due to a less favorable side effect profile compared to remibrutinib, as well as the anti-IgE antibody ligelizumab, which was inferior to omalizumab therapy in a phase 3 study. Overall, there is a high need for new therapeutic strategies to better treat CsU both symptomatically and curatively. This requires a more comprehensive understanding of pathogenesis of the disease in order to develop new targeted therapies.

Local targeting of TSLP: feat or defeat

The physiological role of airway smooth muscle remains highly elusive given the poor overall understanding of the regulatory elements and their influence in healthy humans [1]. Paradoxically, the pathophysiological contribution of airway smooth muscle contraction to asthma is better understood than the physiological role of this contraction in non-asthmatics: early and late asthmatic responses highlight immediate-immune cell-free and delayed-immune cell-dependent bronchoconstriction, respectively [2]. Reducing the late asthmatic response with the inhaled anti-TSLP antibody ecleralimab raises more questions than providing answers <https://bit.ly/3vOkEIN> We thank David Manley for revising the English in this editorial.

Inhaled anti-TSLP antibody fragment, ecleralimab, blocks responses to allergen in mild asthma.

Thymic stromal lymphopoietin (TSLP) is a key upstream regulator driving allergic inflammatory responses. We evaluated the efficacy and safety of ecleralimab, a potent inhaled neutralising antibody fragment against human TSLP, using allergen inhalation challenge (AIC) in subjects with mild atopic asthma. This was a 12-week, randomised, double-blind, placebo-controlled, parallel-design, multicentre allergen bronchoprovocation study conducted at 10 centres across Canada and Germany. Subjects aged 18-60 years with stable mild atopic asthma were randomised (1:1) to receive 4 mg once-daily inhaled ecleralimab or placebo. Primary end-points were the allergen-induced change in forced expiratory volume in 1 s (FEV1) during the late asthmatic response (LAR) measured by area under the curve (AUC3-7h) and maximum percentage decrease (LAR%) on day 84, and the safety of ecleralimab. Allergen-induced early asthmatic response (EAR), sputum eosinophils and fractional exhaled nitric oxide (F ENO) were secondary and exploratory end-points. 28 subjects were randomised to ecleralimab (n=15) or placebo (n=13). On day 84, ecleralimab significantly attenuated LAR AUC3-7h by 64% (p=0.008), LAR% by 48% (p=0.029), and allergen-induced sputum eosinophils by 64% at 7 h (p=0.011) and by 52% at 24 h (p=0.047) post-challenge. Ecleralimab also numerically reduced EAR AUC0-2h (p=0.097) and EAR% (p=0.105). F ENO levels were significantly reduced from baseline throughout the study (p<0.05), except at 24 h post-allergen (day 43 and day 85). Overall, ecleralimab was safe and well tolerated. Ecleralimab significantly attenuated allergen-induced bronchoconstriction and airway inflammation, and was safe in subjects with mild atopic asthma.

Targeting interleukin-33 and thymic stromal lymphopoietin pathways for novel pulmonary therapeutics in asthma and COPD.

Interleukin-33 (IL-33) and thymic stromal lymphopoietin (TSLP) are alarmins that are released upon airway epithelial injury from insults such as viruses and cigarette smoke, and play critical roles in the activation of immune cell populations such as mast cells, eosinophils and group 2 innate lymphoid cells. Both cytokines were previously understood to primarily drive type 2 (T2) inflammation, but there is emerging evidence for a role for these alarmins to additionally mediate non-T2 inflammation, with recent clinical trial data in asthma and COPD cohorts with non-T2 inflammation providing support. Currently available treatments for both COPD and asthma provide symptomatic relief with disease control, improving lung function and reducing exacerbation rates; however, there still remains an unmet need for further improving lung function and reducing exacerbations, particularly for those not responsive to currently available treatments. The epithelial cytokines/alarmins are involved in exacerbations; biologics targeting TSLP and IL-33 have been shown to reduce exacerbations in moderate-to-severe asthma, either in a broad population or in specific subgroups, respectively. For COPD, while there is clinical evidence for IL-33 blockade impacting exacerbations in COPD, clinical data from anti-TSLP therapies is awaited. Clinical data to date support an acceptable safety profile for patients with airway diseases for both anti-IL-33 and anti-TSLP antibodies in development. We examine the roles of IL-33 and TSLP, their potential use as drug targets, and the evidence for target patient populations for COPD and asthma, together with ongoing and future trials focused on these targets.

Targeting thymic stromal lymphopoietin for the treatment of severe eosinophilic asthma

Asthma is a heterogenous chronic inflammatory airway disease comprising of four phenotypes classified based on sputum cytology, which differ in immunopathophysiology, disease severity, and response to pharmacological therapy. The phenotypes of asthma include eosinophilic, neutrophilic, paucigranulocytic, and mixed cellularity. Eosinophilic asthma affects about 40-60% of all asthma cases. It is associated with atopy, eczema, allergic rhinitis, aspirin exacerbated respiratory disease, and chronic rhinosinusitis with nasal polyps. The airway epithelium plays an important role in initiating eosinophilic inflammation, and in the pathogenesis of eosinophilic asthma. Injured or damaged airway epithelium release three cytokines, such as interleukin-25 (IL-25, IL-33, and thymic stromal lymphopoietin (TSLP). Epithelial cytokines also known as alarmins act in concert and synergistically in promoting eosinophilic inflammation, airway hyperresponsiveness, and remodeling. Targeted inhibition of epithelial cytokines is an attractive and precise approach to treat eosinophilic asthma. There are no approved biologics targeting IL-25, and IL-33 for the treatment of eosinophilic asthma. Tezepelumab an anti-TSLP monoclonal antibody is the only anti-alarmin biologic approved for the treatment of severe asthma irrespective of the phenotype. It is effective in reducing the exacerbation rates, and improves lung function, and health related quality of life.

Sounding the alarmins-The role of alarmin cytokines in asthma.

The alarmin cytokines thymic stromal lymphopoietin (TSLP), interleukin (IL)-33, and IL-25 are epithelial cell-derived mediators that contribute to the pathobiology and pathophysiology of asthma. Released from airway epithelial cells exposed to environmental triggers, the alarmins drive airway inflammation through the release of predominantly T2 cytokines from multiple effector cells. The upstream positioning of the alarmins is an attractive pharmacological target to block multiple T2 pathways important in asthma. Blocking the function of TSLP inhibits allergen-induced responses including bronchoconstriction, airway hyperresponsiveness, and inflammation, and subsequent clinical trials of an anti-TSLP monoclonal antibody, tezepelumab, in asthma patients demonstrated improvements in lung function, airway responsiveness, inflammation, and importantly, a reduction in the rate of exacerbations. Notably, these improvements were observed in patients with T2-high and with T2-low asthma. Clinical trials blocking IL-33 and its receptor ST2 have also shown improvements in lung function and exacerbation rates; however, the impact of blocking the IL-33/ST2 axis in T2-high versus T2-low asthma is unclear. To date, there is no evidence that IL-25 blockade is beneficial in asthma. Despite the considerable overlap in the cellular functions of IL-25, IL-33, and TSLP, they appear to have distinct roles in the immunopathology of asthma.

TSLP activates the production of IFN-γ via CD8-positive T cells in recurrent tonsillitis

The role of thymic stromal lymphopoietin (TSLP) in chronic infection is not well understood. We report an increased number of cluster of differentiation 8 (CD8+ T) cells and higher expression of TSLP in the tonsil tissues of patients with recurrent tonsillitis as compared to that in the tonsil tissues of patients with tonsillar hypertrophy. Stimulation of tonsil CD8+ T cells with TSLP in the recurrent tonsillitis group resulted in higher production of interferon gamma (IFN-γ) and increased cell proliferation when compared to that in the tonsillar hypertrophy group. These results suggest the possibility that recurrent infection of tonsils may enhance local CD8+ T cell proliferation and IFN-γ and TSLP production. Anti-TSLP antibodies, which are potential therapeutic agents in allergic diseases, could have beneficial effects in patients with recurrent tonsillitis.

Effects of combination treatment with tezepelumab and allergen immunotherapy on nasal responses to allergen: A randomized controlled trial

Thymic stromal lymphopoietin (TSLP) has been shown to play a central role in the initiation and persistence of allergic responses. We evaluated whether tezepelumab, a human monoclonal anti-TSLP antibody, improved the efficacy of subcutaneous allergen immunotherapy (SCIT) and promoted the development of tolerance in patients with allergic rhinitis. We conducted a double-blind parallel design trial in patients with cat allergy. Atotal of 121 patients were randomized to receive either intravenous tezepelumab plus subcutaneous cat SCIT, cat SCIT alone, tezepelumab alone, or placebo for 52 weeks, followed by 52 weeks of observation. Nasal allergen challenge (NAC), skin testing, and blood and nasal samples were obtained throughout the study. At week 52, the NAC-induced total nasal symptom scores (TNSS) (calculated as area under the curve [AUC0-1h] and as peak score [Peak0-1h] during the first hour after NAC) were significantly reduced in patients receiving tezepelumab/SCIT compared to SCIT alone. At week 104, one year after stopping treatment, the primary end point TNSS AUC0-1h was not significantly different in the tezepelumab/SCIT group compared to SCIT alone, while TNSS Peak0-1h was significantly lower in those receiving combination treatment versus SCIT. Transcriptomic analysis of nasal epithelial samples demonstrated that treatment with the combination of SCIT/tezepelumab, but neither monotherapy, caused persistent downregulation of a gene network related to type 2 inflammation that was associated with improvement in NAC responses. Inhibition of TSLP augments the efficacy of SCIT during therapy and may promote tolerance after a 1-year course of treatment. (ClinicalTrials.gov NCT02237196).

Roseburia intestinalis stimulates TLR5-dependent intestinal immunity against Crohn's disease.

SummaryBackgroundCrohn's disease (CD) is a chronic inflammatory disorder characterized by intestinal immune dysfunction. Multiple factors, including gut dysbiosis, are involved in the pathogenesis of CD. However, the effect of commensal bacteria on controlling the inflammatory response in individuals with CD remains unclear.MethodsWe detected Toll-like receptor 2 (TLR2), TLR4, and TLR5 expression in Roseburia intestinalis (R. intestinalis)-treated mice with 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis. Then, we quantified the signs of colonic inflammation, the proportion of regulatory T cells (Tregs) and the expression of thymic stromal lymphopoietin (TSLP) and transforming growth factor (TGF)-β in TLR-5-deficient (Tlr5−/−) mice, bone marrow chimera mice (generated using wild-type (WT) and Tlr5−/− mice), and anti-TSLP/anti-TGFβ-treated C57BL/6 mice with colitis induced by TNBS. In vitro, we used the lipopolysaccharide (LPS)-stimulated human intestinal epithelial cell line Caco-2 as an inflammatory colon cell model treated with or without the TLR5-siRNA intervention in the presence of R. intestinalis and incubated human monocyte-derived dendritic cells (DCs) with the supernatant of Caco-2 cells. Then, we cocultured human CD4+ T cells with the aforementioned DCs to determine the differentiation of Tregs. Additionally, samples from patients with CD were collected to analyse the correlation between TLR5/TSLP/TGFβ expression and the percentage of R. intestinalis.FindingsHere, we show that R. intestinalis inhibits the development of CD by increasing the differentiation of anti-inflammatory Tregs. Mechanistically, R. intestinalis stimulates TSLP production in intestinal epithelial cells (IECs) through TLR5 but not TLR2 or TLR4. TSLP produced by IECs specifically induces the secretion of interleukin-10 (IL-10) and TGFβ from DCs, which is necessary for subsequent Treg differentiation. Consequently, the depletion of TLR5 (using Tlr5−/− mice) or inhibition of TSLP (using anti-TSLP neutralizing antibodies) attenuates the protective effect of R. intestinalis on experimental colitis in mice. Importantly, the expression of TSLP in patients with CD is positively correlated with the level of R. intestinalis.InterpretationThese findings reveal the previously unknown mechanism of R. intestinalis-mediated intestinal immune regulation, which may provide the basis for new therapeutic strategies for CD.FundingThis work was funded by the National Natural Science Foundation of China (81670504 and 81970494), the Key Project of Research and Development Plan of Hunan Province (2019SK2041) and the Changsha Municipal Natural Science Foundation (kq2014258).

Abstract 2089: Evaluating in vivo efficacy of anti-TSLP antibodies in humanized B-hTSLP/hTSLPR mice

Abstract Expression of the epithelial cytokine, thymic stromal lymphopoietin (TSLP), has been observed across several barrier surfaces and plays a critical role in both physiological and pathological processes. Via T helper (Th) 2 cytokine production, TSLP has been implicated in asthma, atopic dermatitis, inflammatory bowel disease, multiple sclerosis, and chronic obstructive pulmonary disease. This range in which TSLP exerts its effects on inflammatory diseases makes the TSLP/TSLPR axis an attractive therapeutic target. At Biocytogen, we generated a novel TSLP/TSLPR double humanized mouse model that enables in vivo assessment of human anti-TSLP and anti-TSLPR antibodies. In our B-hTSLP/hTSLPR mice, the murine Tslp and Tslpr genes are replaced with the human TSLP and TSLPR genes by homologous recombination. ELISA analysis showed that human TSLP (after induction with calcipotriol) was exclusively detectable in homozygous B-hTSLP/hTSLPR mice compared to wild type mice. Similarly, flow cytometry analysis indicated TSLPR expression was detectable in monocytes, neutrophils, macrophages, total DCs, cDC1, cDC2, Mo-DC and Pre-DC. Percentages of T cells, B cells, NK cells, DCs, granulocytes, monocytes, macrophages, CD8+ T cells, CD4+ T cells and Tregs in homozygous B-hTSLP/hTSLPR mice were comparable to those in the wild type mice, demonstrating that introduction of human TSLP and TSLPR in place of their mouse counterparts did not impair the overall development, differentiation, or distribution of these cell types. Furthermore, using an asthma mouse model via induction with ovalbumin (OVA), we showed that an anti-TSLP antibody (Tezepelumab, synthesized in house) was efficacious in controlling asthma progression in B-hTSLP/hTSLPR mice. Altogether, B-hTSLP/hTSLPR mice are a promising model for preclinical in vivo pharmacodynamic assessment of TSLP antibodies. Citation Format: Shujin Zhang, Yanhui Nie, Jiahui Chang, Veronika Chromikova, Luke (Zhaoxue) Yu, Mari Kuraguchi. Evaluating in vivo efficacy of anti-TSLP antibodies in humanized B-hTSLP/hTSLPR mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2089.

Neutrophils and Asthma.

Although eosinophilic inflammation is characteristic of asthma pathogenesis, neutrophilic inflammation is also marked, and eosinophils and neutrophils can coexist in some cases. Based on the proportion of sputum cell differentiation, asthma is classified into eosinophilic asthma, neutrophilic asthma, neutrophilic and eosinophilic asthma, and paucigranulocytic asthma. Classification by bronchoalveolar lavage is also performed. Eosinophilic asthma accounts for most severe asthma cases, but neutrophilic asthma or a mixture of the two types can also present a severe phenotype. Biomarkers for the diagnosis of neutrophilic asthma include sputum neutrophils, blood neutrophils, chitinase-3-like protein, and hydrogen sulfide in sputum and serum. Thymic stromal lymphoprotein (TSLP)/T-helper 17 pathways, bacterial colonization/microbiome, neutrophil extracellular traps, and activation of nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 pathways are involved in the pathophysiology of neutrophilic asthma and coexistence of obesity, gastroesophageal reflux disease, and habitual cigarette smoking have been associated with its pathogenesis. Thus, targeting neutrophilic asthma is important. Smoking cessation, neutrophil-targeting treatments, and biologics have been tested as treatments for severe asthma, but most clinical studies have not focused on neutrophilic asthma. Phosphodiesterase inhibitors, anti-TSLP antibodies, azithromycin, and anti-cholinergic agents are promising drugs for neutrophilic asthma. However, clinical research targeting neutrophilic inflammation is required to elucidate the optimal treatment.