Respiratory mucosal delivery of next-generation COVID-19 vaccine provides robust protection against both ancestral and variant strains of SARS-CoV-2.

The emerging SARS-CoV-2 variants of concern (VOCs) threaten the effectiveness of current COVID-19 vaccines administered intramuscularly and designed to only target the spike protein. There is a pressing need to develop next-generation vaccine strategies for broader and long-lasting protection. Using adenoviral vectors (Ad) of human and chimpanzee origin, we evaluated Ad-vectored trivalent COVID-19 vaccines expressing spike-1, nucleocapsid, and RdRp antigens in murine models. We show that single-dose intranasal immunization, particularly with chimpanzee Ad-vectored vaccine, is superior to intramuscular immunization in induction of the tripartite protective immunity consisting of local and systemic antibody responses, mucosal tissue-resident memory T cells and mucosal trained innate immunity. We further show that intranasal immunization provides protection against both the ancestral SARS-CoV-2 and two VOC, B.1.1.7 and B.1.351. Our findings indicate that respiratory mucosal delivery of Ad-vectored multivalent vaccine represents an effective next-generation COVID-19 vaccine strategy to induce all-around mucosal immunity against current and future VOC.

Rnf20 inhibition enhances immunotherapy by improving regulatory T cell generation.

BACKGROUND: Allergic disorders are common all over the world. The pathogenesis of allergy is unclear. Therapies for allergic disorders require improvement. Endoplasmic reticulum (ER) stress is one of the factors influencing immune response. The purpose of this study is to improve the effectiveness of immunotherapy for experimental respiratory allergy by targeting the ER stress signal pathway. METHODS: Committed CD4+ T cells were isolated from blood samples collected from patients with allergic rhinitis (AR) and TCR ovalbumin transgenic mice. The effects of TCR engagement and 3-methyl-4-nitrophenol (MNP) on inducing ER stress in committed CD4+ T cells were evaluated. RESULTS: ER stress was detected in antigen-specific CD4+ T cells (sCD4+ T cells) of AR patients. The environmental pollutant MNP increased the expression of the X-binding protein-1 (XBP1) in the committed CD4+ T cells during the TCR engagement. XBP1 mediated the effects of MNP on inhibiting regulatory T cell (Treg) generation. The effects of MNP on induction of protein 20 (Rnf20) in CD4+ T cells were mediated by XBP1. Inhibition of Rnf20 rescued the Treg development from MNP-primed sCD4+ T cells. The ablation of Rnf20 improved the immunotherapy of AR through the restoration of the Treg generation. CONCLUSIONS: ER stress can be detected in CD4+ T cells in TCR engagement. Exposure to MNP exacerbates ER stress in committed CD4+ T cells. Regulation of the ER stress-related Rnf20 expression can restore the generation of Treg from CD4+ T cells of subjects with allergic diseases.

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.

COVID-19: Current knowledge in clinical features, immunological responses, and vaccine development.

The COVID-19 pandemic has unfolded to be the most challenging global health crisis in a century. In 11 months since its first emergence, according to WHO, the causative infectious agent SARS-CoV-2 has infected more than 100 million people and claimed more than 2.15 million lives worldwide. Moreover, the world has raced to understand the virus and natural immunity and to develop vaccines. Thus, within a short 11 months a number of highly promising COVID-19 vaccines were developed at an unprecedented speed and are now being deployed via emergency use authorization for immunization. Although a considerable number of review contributions are being published, all of them attempt to capture only a specific aspect of COVID-19 or its therapeutic approaches based on ever-expanding information. Here, we provide a comprehensive overview to conceptually thread together the latest information on global epidemiology and mitigation strategies, clinical features, viral pathogenesis and immune responses, and the current state of vaccine development.

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.

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.

Mal-deficiency impairs the tolerogenicity of dendritic cell of patients with allergic rhinitis.

The tolerogenic dendritic cell dysfunction is associated with the pathogenesis of immune diseases. Microbial stimulus is required in the maintenance of immune functions. This study aims to elucidate the role of Mal signal in the maintenance of DEC205+ DC (decDC) immune tolerogenic function. In this study, peripheral DCs were collected from allergic rhinitis (AR) patients and healthy control (HC) subjects to assess the functional status of decDCs. An AR murine model was developed to test the role of Mal signals in the maintenance of decDCs' functions. We observed that AR decDCs (decDCs obtained from AR patients) were incompetent in the induction of type 1 regulatory T cells (Tr1 cells). AR decDCs expressed less IL-10 than that in HC decDCs. IL-10 mRNA decayed spontaneously in AR decDCs. Tat-activating regulatory DNA-binding protein-43 (TDP43) protected IL-10 mRNA from decay. AR decDCs expressed lower levels of Mal than that in HC decDCs. Mal depletion resulted in IL-10 mRNA decay in HC decDCs. Reconstitution of Mal in AR decDCs restored the capacity of inducing Tr1 cells and attenuated experimental AR in mice. In conclusion, Mal plays a critical role in the maintenance of decDC's immune tolerogenic function. The absence or insufficient Mal signal impairs decDC's tolerogenic property. Reconstitution of Mal in AR decDCs can restore the immune tolerogenic capacity, which may have translational potential in the treatment of AR and other allergic diseases.

Evaluation of airway hyperresponsiveness in chronic rhinosinusitis: values of sinus computed tomography.

BACKGROUND: Chronic rhinosinusitis (CRS) is tightly linked to airway hyperresponsiveness (AHR) and asthma. However, the practical surrogate parameters for evaluating AHR in patients with CRS remain unclear. OBJECTIVE: To evaluate the diagnostic values of sinus computed tomography for AHR in patients with CRS. METHODS: We performed a prospective, single-blinded study of 125 consecutive patients with CRS. These patients were subdivided into AHR and non-AHR (NAHR) groups based on histamine provocation test results. The following parameters were compared between 2 groups of CRS patients: Lund-Mackay scores, olfactory cleft (OC) scores, and serum eosinophil counts. RESULTS: Fifty-seven patients (45.4%) presented with AHR. The OC scores, the ratio of OC scores to total scores, and the eosinophil counts in the AHR group were significantly higher than those in the NAHR group (P < .001). Multivariate logistic regression revealed that OC scores and eosinophil counts were independent risk factors for asymptomatic AHR (OC scores P < .001 and eosinophil counts P = .010). The OC score had a higher predictive value for AHR (area under curve, 0.800) than eosinophil counts (area under the curve, 0.637). When the OC score was 3 or higher, the sensitivity was 75.0%, specificity was 77.9%, and positive predictive value was 68.8%. CONCLUSION: The findings validate a prospective assessment of sinus computed tomography as a screening tool for AHR in patients with CRS.

TRIM41 contributes to the pathogenesis of airway allergy by compromising dendritic cells' tolerogenic properties.

Dendritic cells (DC) play a crucial role in the initiation of immune responses. TRIM41, an E3 ubiquitin ligase, can facilitate targeting protein degradation. The purpose of this study is to analyze the role of TRIM41 in the pathogenesis of airway allergy (AA) and the impact of regulating TRIM41 on suppressing AA. We observed that the airway DCs of AA mice had a higher expression of Trim41. The expression of Trim41 in airway DCs was associated with the DCs' tolerogenic functions of AA mice. The AA responses, including increased amounts of eosinophil peroxidase, mast cell protease-1, Th2 cytokines, and specific IgE in bronchoalveolar lavage fluids, were positively correlated with the Trim41 expression in mouse airway DCs. TRIM41 induced c-Maf degradation and interfered with the Il10 expression in airway DCs, which could be counteracted by inhibiting TRIM41. Regulation of TRIM41 mitigated experimental AA responses.

Modulating endoplasmic reticulum stress attenuates mast cell degranulation.

OBJECTIVES: Degranulation of mast cells leads to direct allergic symptoms. The underlying mechanism needs to be explored further. Endoplasmic reticulum (ER) stress is involved in the pathogenesis of allergic conditions. The objective of this study is to gain a better understanding of the mechanism of mast cell degranulation. METHODS: Bone marrow derived mast cells and mast cells isolated from the airway tissues were prepared. The role of ER stress in mediating the release of mast cells was tested. RNA sequencing (RNAseq) was used to investigate the genetic activities of mast cells. RESULTS: Our observation showed that sensitization increased ER stress in mast cells. X-box-1 binding protein (XBP1) activity was linked to mast cell degranulation. Modulation of ER stress or XBP1 expression regulates the release of the mast cell mediator. XBP1 promoted the mediator release of mast cells by activating spleen tyrosine kinase (Syk). Activation of eukaryotic initiation factor 2a (eIF2a) inhibited XBP1 in mast cells. Semaphorin 3A was effective in preventing experimental allergic rhinitis (AR) due to its ability to suppress the release of mast cell mediators. CONCLUSIONS: ER stress is associated with the mast cell degranulation. By inhibiting XBP1, the crucial molecule of ER stress, mast cell degranulation can be suppressed and experimental AR can be mitigated.

[Two children with late-onset congenital central hypoventilation syndrome].

Two children with late-onset congenital central hypoventilation syndrome were reported, one of whom was male and had no abnormal manifestations after birth, respiratory failure occurs at the age of 1 year and 6 months. After being hospitalized, he was treated with oxygen inhalation and non-invasive ventilation, but carbon dioxide retention could not be corrected. After one month of tracheal intubation, he was failure to wean from ventilator, so tracheostomy was performed. He needs a ventilator to help breath while sleeping, and can breath autonomously during the day without ventilator. The other case was a female, with no abnormalities after birth. At the age of 11 months, she developed respiratory failure. During sleep, the child needs non-invasive assisted ventilation through a nasal mask, and during the day, she breathed autonomously.Two patients were followed up forever 2 years and their growth and development were normal.

[Mechanism of Der f 1/IGF-1 nanoparticle promoting the production of regulatory T cell].

Objective:To prepare PLGA nanoparticles loaded with Der f 1/IGF-1（Der f 1/IGF-1 NPs） and investigate their role in promoting the formation of Treg cells. Methods:NPs coated with Der f 1/IGF-1 were prepared by double emulsion method and their physicochemical properties and cumulative release rate in vitro were analyzed. After pretreatment, BMDC was divided into Saline group, Blank NPs group, Der f 1/IGF-1 group and Der f 1/IGF-1 NPs group. Determination of the expression of IL-10 and TGF-ß in BMDC by ELISA. The number of Treg cells was detected by flow cytometry. Results:The results showed that Der f 1/IGF-1 NPs were spherical structures, with good dispersion, particle size less than 200 nm, negative charge and stable slow-release effect of Zeta potential. After BMDC pretreatment, the expression levels of TGF-ß and IL-10 in BMDC cells in the Der f 1/IGF-1 NPs group were significantly increased compared with the Blank NPs group, and the difference was statistically significant（P<0.001）. After co-culture with CD4+ T cells, the proportion of Treg cells produced in the Der f 1/IGF-1 NPs group was significantly increased, and the difference was statistically significant（P<0.001）. Conclusion:Der f 1/IGF-1 NPs can induce Treg cell generation in vitro. This study provides a new and more effective method for the reconstruction of immune tolerance dysfunction.

Subcutaneous BCG vaccination protects against streptococcal pneumonia via regulating innate immune responses in the lung.

Bacillus Calmette-Guérin (BCG) still remains the only licensed vaccine for TB and has been shown to provide nonspecific protection against unrelated pathogens. This has been attributed to the ability of BCG to modulate the innate immune system, known as trained innate immunity (TII). Trained innate immunity is associated with innate immune cells being in a hyperresponsive state leading to enhanced host defense against heterologous infections. Both epidemiological evidence and prospective studies demonstrate cutaneous BCG vaccine-induced TII provides enhanced innate protection against heterologous pathogens. Regardless of the extensive progress made thus far, the effect of cutaneous BCG vaccination against heterologous respiratory bacterial infections and the underlying mechanisms still remain unknown. Here, we show that s.c. BCG vaccine-induced TII provides enhanced heterologous innate protection against pulmonary Streptococcus pneumoniae infection. We further demonstrate that this enhanced innate protection is mediated by enhanced neutrophilia in the lung and is independent of centrally trained circulating monocytes. New insight from this study will help design novel effective vaccination strategies against unrelated respiratory bacterial pathogens.

The transcription factor XBP1 in dendritic cells promotes the TH2 cell response in airway allergy.

Dendritic cells (DCs) that express T cell immunoglobulin domain molecule-4 (TIM4), a cell surface receptor for phosphatidylserine, induce T helper 2 (TH2) cell responses and allergic reactions. We elucidated the role of the transcription factor X-box-binding protein-1 (XBP1) in the induction of the TH2 cell response through its role in generating TIM4+ DCs. We found that XBP1 was required for TIM4 mRNA and protein expression in airway DCs in response to the cytokine interleukin-2 (IL-2) and that this pathway was required for TIM4 expression on DCs in response to the allergens PM2.5 and Derf1. The IL-2-XBP1-TIM4 axis in DCs contributed to Derf1/PM2.5-induced, aberrant TH2 cell responses in vivo. An interaction between the guanine nucleotide exchange factor Son of sevenless-1 (SOS1) and the GTPase RAS promoted XBP1 and TIM4 production in DCs. Targeting the XBP1-TIM4 pathway in DCs prevented or alleviated experimental airway allergy. Together, these data suggest that XBP1 is required for TH2 cell responses by inducing the development of TIM4+ DCs, which depends on the IL-2-XBP1-SOS1 axis. This signaling pathway provides potential therapeutic targets for the treatment of TH2 cell-dependent inflammation or allergic diseases.

The Long-Term Mechanical Properties of BS Perpendicular to the Grain.

As a modern bamboo composite with good mechanical properties, bamboo scrimber (BS) has achieved prominence in the sustainable architecture field. When used as a structural material, it is inevitably under continual tension perpendicular to the grain, therefore its mechanical response under long-term loading is significant for structural design. In this study, tensile tests were conducted on BS under short-term and long-term loads perpendicular to the grain. The duration of load (DOL) effect on BS perpendicular to grain and its creep effect were analyzed. Compared with BS parallel to the grain, the DOL effect on BS perpendicular to the grain was less severe, and the capacity for creep resistance was weaker. The threshold stress ratio and relative creep strain of BS perpendicular to the grain were 0.40 and 0.87, respectively. It was found that the DOL models and the viscoelastic model accurately predicted the DOL factor and creep strain. This study provides a scientific reference for the safe lifetime service of BS in practical engineering.

[Preliminary study on efficacy and safety of submucosal plasma ablation of inferior turbinate in children with allergic rhinitis complicated with obstructive sleep apnea syndrome].

Objective:This study aimed to investigate the long-term clinical efficacy and safety of inferior turbinate submucosal plasma ablation combined with or without tonsillar and adenoid surgery in children with allergic rhinitis（AR） combined with obstructive sleep apnea syndrome（OSAS） who were ineffective after conservative systemic treatment. Methods:A total of 43 children with AR complicated with OSAS who met the inclusion criteria among 68 children hospitalized from January 2019 to February 2022 were retrospectively analyzed. The data were collected, including the clinical characteristics, surgical methods perioperative management and prevention and treatment of complications. Moreover, one year follow-up was performed to compare the VAS scores of children before and after surgery, and to evaluate their mid-term and long-term outcomes. Results:The average operation time was 36 minutes, meanwhile, the intraoperative blood was limited. The symptoms of nasal congestion, runny nose, sleep snoring, and mouth breathing were significantly improved after operation, and the results were satisfactory after one-year follow-up without complications such as bleeding, hematoma, intraoperative adhesion, and nasal dryness. Conclusion:Submucosal plasma ablation of inferior turbinate with or without tonsillectomy adenoidectomy in children with AR can effectively improve the clinical symptoms of AR combined with OSAS children who are ineffective after conservative treatment. It can improve the symptoms of sleep-disordered breathing such as sleep snoring and mouth breathing, with good mid-and long-term curative effects and fewer complications, which is an effective and safe treatment for children with AR combined with OSAS.

TAFA4-IL-10 axis potentiate immunotherapy for airway allergy by induction of specific regulatory T cells.

Allergen-specific immunotherapy (AIT) is the main treatment for allergic diseases. The therapeutic efficacy of AIT has to be improved. Neuropeptides, such as TAFA4, have immune-regulating features. The objective of this study is to promote the efficacy of AIT in experimental allergic rhinitis (AR) by the concurrent use of TAFA chemokine as a family member 4 (TAFA4). In this study, an AR mouse model was developed using ovalbumin (OVA) as the specific antigen. The AR response was assessed in mice after treatment with AIT or/and TAFA4. We found that exposure to TAFA4 activated dendritic cells (DCs) in the airway tissues. Activation of DC by TAFA4 resulted in the expression of IL-10. TAFA4 also promoted the activities of c-Maf inducing protein. The FPR1-MyD88-AKT signal pathway was associated with the TAFA4-induced Il10 expression in the DCs. Co-administration of AIT/TAFA4 attenuated the AR response in mice by inducing antigen-specific Tr1 cells. In conclusion, TAFA4 induces the expression of IL-10 in DCs. Acting as an adjuvant, TAFA4 significantly improves AIT's therapeutic efficacy against AR by inducing antigen-specific Tr1 cells.