Search

Dendritic cells (DCs) that express T cell immunoglobulin domain molecule-4 (TIM4), a cell surface receptor for phosphatidylserine, induce T helper 2 (T H 2) cell responses and allergic reactions. We elucidated the role of the transcription factor X-box-binding protein-1 (XBP1) in the induction of the T H 2 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 T H 2 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 T H 2 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 T H 2 cell-dependent inflammation or allergic diseases.

Background: Allergen-specific immunotherapy (AIT) is the mainstay in the treatment of allergic diseases, but the therapeutic effects of AIT need to be improved. CD38 + B cells are an immune cell fraction involved in the pathogenesis of allergic diseases as well as in immune regulation., Objective: We sought to elucidate the role of antigen-specific CD38 + B cells in AIT., Methods: An analysis was carried out on AIT results of 48 patients with perennial allergic rhinitis (AR), among which peripheral blood immune cells were analyzed by flow cytometry; serum cytokine levels were determined by ELISA. An AR murine model was developed to test the role of CD38 + B cells in AIT., Results: A fraction of antigen-specific CD38 + B cell was detected in AR patients. CD38 + B-cell frequency was negatively correlated with the therapeutic effects of AIT. A negative correlation was detected between the CD38 + B-cell frequency and regulatory T-cell frequency in AR patients treated with AIT. Exposure to specific antigens induced CD38 + B cells to produce IL-6, that converted Treg cells to T H 17 cells. Coadministration of anti-CD38 antibody significantly promoted the therapeutic effects of AIT., Conclusions: Antigen-specific CD38 + B cells compromise AIT effects by producing IL-6 to convert regulatory T cells to T H 17 cells. Inhibition of CD38 + B cells promotes the effects of AIT., (Copyright © 2022 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

IL-10-expressing regulatory B cells (B10 cells) are dysfunctional in patients with many immune disorders. The underlying mechanism remains to be further elucidated. Glutamine is an essential nutrient for cell metabolism. This study aims to elucidate the role of glutaminolysis in maintaining the immune regulatory capacity in B10 cells. Peripheral blood samples were collected from 50 patients with allergic rhinitis and 50 healthy control subjects. B cells were isolated from blood samples by cell sorting with flow cytometry. The role of glutaminolysis in regulating B10 cell activities was assessed by immunological and biochemical approaches. The results showed that B cells from patients with allergic rhinitis expressed low levels of the transporter of glutamine and neutral amino acid. Glutaminolysis was required in the IL-10 expression in B cells. The glutamine catabolism was required in B10 cell generation. The mTOR activation mediated the glutaminolysis-associated B10 cell induction, and the suppression of the B cell glycogen synthase kinase-3 (GSK3) activation. GSK3 activation suppressed IL-10 expression in B cells. Inhibition of GSK3 enhanced IL-10 expression in B cells and alleviated experimental allergic rhinitis by generating immune competent type 1 regulatory T cells., (© 2022. The Author(s), under exclusive licence to Society for Mucosal Immunology.)

The infection of coronavirus disease (COVID-19) seriously threatens human life. It is urgent to generate effective and safe specific antibodies (Abs) against the pathogenic elements of COVID-19. Mice were immunized with SARS-CoV-2 spike protein antigens: S ectodomain-1 (CoV, in short) mixed in Alum adjuvant for 2 times and boosted with CoV weekly for 6 times. A portion of mice were treated with Maotai liquor (MTL, in short) or/and heat stress (HS) together with CoV boosting. We observed that the anti-CoV Ab was successfully induced in mice that received the CoV/Alum immunization for 2 times. However, upon boosting with CoV, the CoV Ab production diminished progressively; spleen CoV Ab-producing plasma cell counts reduced, in which substantial CoV-specific Ab-producing plasma cells (sPC) were apoptotic. Apparent oxidative stress signs were observed in sPCs; the results were reproduced by exposing sPCs to CoV in the culture. The presence of MTL or/and HS prevented the CoV-induced oxidative stress in sPCs and promoted and stabilized the CoV Ab production in mice in re-exposure to CoV. In summary, CoV/Alum immunization can successfully induce CoV Ab production in mice that declines upon reexposure to CoV. Concurrent administration of MTL/HS stabilizes and promotes the CoV Ab production in mice., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2022 Li-Hua Mo et al.)

The mechanism of antigen-specific regulatory T cell (T reg ) induction is not yet fully understood. Curcumin has an immune regulatory function. This study aims to induce antigen-specific T regs by employing extracellular vesicles (EVs) that carry two types of T cell activators. Two types of T cell activators, ovalbumin (OVA)/major histocompatibility complex-II (MHC-II) and tetramethylcurcumin (FLLL31) (a curcumin analog) were carried by dendritic cell-derived extracellular vesicles, designated OFexo. A murine model of allergic rhinitis (AR) was developed with OVA as the specific antigen. AR mice were treated with a nasal instillation containing OFexo. We observed that OFexo recognized antigen-specific T cell receptors (TCR) on CD4 + T cells and enhanced Il10 gene transcription in CD4 + T cells. Administration of the OFexo-containing nasal instillation induced antigen-specific type 1 T regs (Tr1 cells) in the mouse airway tissues. OFexo-induced Tr1 cells showed immune suppressive functions on CD4 + T cell proliferation. Administration of OFexo efficiently alleviated experimental AR in mice. In conclusion, OFexo can induce antigen-specific Tr1 cells that can efficiently alleviate experimental AR. The results suggest that OFexo has the translational potential to be employed for the treatment of AR or other allergic disorders., (© 2021 British Society for Immunology.)