CagA-specific Gastric CD8+ Tissue-Resident T Cells Control Helicobacter pylori During the Early Infection Phase.

BACKGROUND & AIMS: Infection with Helicobacter pylori strongly affects global health by causing chronic gastritis, ulcer disease, and gastric cancer. Although extensive research into the strong immune response against this persistently colonizing bacterium exists, the specific role of CD8+ T cells remains elusive. METHODS: We comprehensively characterize gastric H pylori-specific CD8+ T-cell responses in mice and humans by flow cytometry, RNA-sequencing, immunohistochemistry, and ChipCytometry, applying functional analyses including T-cell depletion, H pylori eradication, and ex vivo restimulation. RESULTS: We define CD8+ T-cell populations bearing a tissue-resident memory (TRM) phenotype, which infiltrate the gastric mucosa shortly after infection and mediate pathogen control by executing antigen-specific effector properties. These induced CD8+ tissue-resident memory T cells (TRM cells) show a skewed T-cell receptor beta chain usage and are mostly specific for cytotoxin-associated gene A, the distinctive oncoprotein injected by H pylori into host cells. As the infection progresses, we observe a loss of the TRM phenotype and replacement of CD8+ by CD4+ T cells, indicating a shift in the immune response during the chronic infection phase. CONCLUSIONS: Our results point toward a hitherto unknown role of CD8+ T-cell response in this bacterial infection, which may have important clinical implications for treatment and vaccination strategies against H pylori.

Immune Biology and Persistence of Helicobacter pylori in Gastric Diseases.

Helicobacter pylori is a prevalent pathogen, which affects more than 40% of the global population. It colonizes the human stomach and persists in its host for several decades or even a lifetime, if left untreated. The persistent infection has been linked to various gastric diseases, including gastritis, peptic ulcers, and an increased risk for gastric cancer. H. pylori infection triggers a strong immune response directed against the bacterium associated with the infiltration of innate phagocytotic immune cells and the induction of a Th1/Th17 response. Even though certain immune cells seem to be capable of controlling the infection, the host is unable to eliminate the bacteria as H. pylori has developed remarkable immune evasion strategies. The bacterium avoids its killing through innate recognition mechanisms and manipulates gastric epithelial cells and immune cells to support its persistence. This chapter focuses on the innate and adaptive immune response induced by H. pylori infection, and immune evasion strategies employed by the bacterium to enable persistent infection.

Genome-Wide ChIP-seq and RNA-seq Analyses of STAT3 Target Genes in TLRs Activated Human Peripheral Blood B Cells.

Toll like receptors (TLRs) induced response plays a vital role in B-cell development and activation, in which TLR7-mediated and TLR9-mediated response interact together and play antagonistic or cooperative roles at different situations. Previous studies showed that the transcription factor signal transducer and activator of transcription (STAT) 3 was one of the key transcriptional factors (TFs) needed for both TLR7 and TLR9 signaling in B cell, and patients with autosomal dominant hyper IgE syndromes (AD-HIES) due to STAT3 mutations having defective TLRs response in B cells. However, how STAT3 affects its target genes and the downstream signaling pathways in B cell upon TLRs stimulation remains unclarified on a genome-wide level. ChIP-seq and RNA-seq was used in this study to identify the STAT3 targets in response to TLRs stimulation in human B cell. STAT3 ChIP-seq results showed a total of 611 and 2,289 differential STAT3-binding sites in human B cell after TLR7 and TLR9 agonists stimulation, respectively. RNA-seq results showed 1,186 and 1,775 differentially expressed genes after TLR7 and TLR9 activation, respectively. We identified 47 primary STAT3 target genes after TLR7 activation and 189 target genes after TLR9 activation in B cell by integration of STAT3 ChIP-seq and RNA-seq data. Among these STAT3 primary targets, we identified 7 TFs and 18 TFs for TLR7 and TLR9 response, respectively. Besides, we showed that STAT3 might regulate TLR9, but not TLR7 response in B cells through directly regulating integrin signaling pathway, which might further affect the antagonism between TLR7 and TLR9 signaling in B cell. Our study provides insights into the molecular mechanism of human TLRs response in B cell and how it can be regulated, which helps to better understand and modulate TLR-mediated pathogenic immune responses in B cell.

Defective Toll-Like Receptors Driven B Cell Response in Hyper IgE Syndrome Patients With STAT3 Mutations.

Autosomal dominant hyper-IgE syndrome (AD-HIES) is a rare inherited primary immunodeficient disease (PIDs), which is caused by STAT3 gene mutations. Previous studies indicated a defective Toll-like receptor (TLR) 9-induced B cell response in AD-HIES patients, including proliferation, and IgG production. However, the other TLRs-mediated B cell responses in AD-HIES patients were not fully elucidated. In this study, we systematically studied the B cell response to TLRs signaling pathways in AD-HIES patients, including proliferation, activation, apoptosis, cytokine, and immunoglobulin production. Our results showed that the TLRs-induced B cell proliferation and activation was significantly impaired in AD-HIES patients. Besides, AD-HIES patients had defects in TLRs-induced B cell class switch, as well as IgG/IgM secretion and IL-10 production in B cells. Taken together, we first systematically reported the deficiency of TLRs driven B cell response in AD-HIES patients, which help to have a better understanding of the pathology of AD-HIES.

A Biodegradable Mg-Based Alloy Inhibited the Inflammatory Response of THP-1 Cell-Derived Macrophages Through the TRPM7-PI3K-AKT1 Signaling Axis.

Mg-based alloys might be ideal biomaterials in clinical applications owing to favorable mechanical properties, biodegradability, biocompatibility, and especially their anti-inflammatory properties. However, the precise signaling mechanism underlying the inhibition of inflammation by Mg-based alloys has not been elucidated. Here, we investigated the effects of a Mg-2.1Nd-0.2Zn-0.5Zr alloy (denoted as JDBM) on lipopolysaccharide (LPS)-induced macrophages. THP-1 cell-derived macrophages were cultured on JDBM, Ti-6Al-4V alloy (Ti), 15% extract of JDBM, and 7.5 mM of MgCl2 for 1 h before the addition of LPS for an indicated time; the experiments included negative and positive controls. Our results showed JDBM, extract, and MgCl2 could decrease LPS-induced tumor necrosis factor (TNF) and interleukin (IL)-6 expression. However, there were no morphologic changes in macrophages on Ti or JDBM. Mechanically, extract and MgCl2 downregulated the expression of toll-like receptor (TLR)-4 and MYD88 compared with the positive control and inhibited LPS-induced nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways by inactivation of the phosphorylation of IKK-α/ß, IKß-α, P65, P38, and JNK. Additionally, the LPS-induced reactive oxygen species (ROS) expression was also decreased by extract and MgCl2. Interestingly, the expression of LPS-induced TNF and IL-6 could be recovered by knocking down TRPM7 of macrophages, in the presence of extract or MgCl2. Mechanically, the activities of AKT and AKT1 were increased by extract or MgCl2 with LPS and were blocked by a PI3K inhibitor, whereas siRNA TRPM7 inhibited only AKT1. Together, our results demonstrated the degradation products of Mg-based alloy, especially magnesium, and resolved inflammation by activation of the TRPM7-PI3K-AKT1 signaling pathway, which may be a potential advantage or target to promote biodegradable Mg-based alloy applications.

Immunoregulatory effect of human ß-defensin 1 on neonatal cord blood monocyte-derived dendritic cells and T cells.

The relationship between breastfeeding and infant health has been well elucidated in past decades. Our previous study has shown that human ß-defensin 1 (hBD-1) in human breast milk plays a protective role in reducing the incidence of upper respiratory infection in infants younger than 6 months. In the present study, we aim to reveal the mechanism underlying the protective role of hBD-1 by focusing on its immunoregulatory function in neonates. Cord blood (CB) from newborns' umbilical cords, which can simulate many of the neonatal symptoms, was used to study the immunomodulatory role of hBD-1 in neonates in vitro. Our results showed that hBD-1 promotes the GM-CSF- and IL-4-driven differentiation of neonatal umbilical CB monocytes to immature dendritic cells (DCs) and the final maturation of CB monocyte-derived DCs (moDCs) induced by LPS but not inflammatory cytokine production. In addition, hBD-1 inhibits apoptosis in neonatal moDCs through CCR6, which might be a possible mechanism of the hBD-1-induced phenotypes in moDCs. Furthermore, we found that hBD-1 promotes the proliferation and activation, but not the maturation, of neonatal CB CD4 + T cells. These results extend the immunoregulatory effects of hBD-1 and provide a potential mechanism for the protective role of hBD-1 in early infants, which will inform the development of infant nutrition, novel vaccines and anti-infective strategies in the future.

Degradation Products of Polydopamine Restrained Inflammatory Response of LPS-Stimulated Macrophages Through Mediation TLR-4-MYD88 Dependent Signaling Pathways by Antioxidant.

Polydopamine (PDA) has a promising application as coating of biomaterials due to its favorable degradability and bioadaptability. However, its bioactivity, such as anti-inflammatory capacity, was still little known. Herein, we investigated whether degradable products of PDA could affect inflammatory response in lipopolysaccharide (LPS)-stimulated human THP-1-derived macrophages. The supernatants containing degradation products of PDA, annotated as PDA extracts, were collected after PDA being immersed in cell culture medium for 3 days. Wherein, the composition of the degradation products was analyzed by HPLC assay. Collected PDA extracts were diluted into 100%, 50%, and 25% of original concentration, respectively, to evaluate their anti-inflammatory ability on LPS-induced macrophages from the expression levels of pro-inflammatory cytokines to associated molecular mechanism. Our results showed that the PDA extracts were mainly composed of dopamine, quinine, and PDA segments. Furthermore, macrophages showed no cytotoxicity after PDA extract treatment with or without LPS, while the release levels of TNF-α and IL-6 by LPS-induced macrophages were decreased in dose-dependent by PDA extract treatment. Additionally, TLR-4 and MYD88 expression in protein and RNA level were downregulated by PDA extracts in LPS-induced macrophages. Similarly, PDA extracts effectively inhibited LPS-induced NF-κB trans-locating into nuclear by inactivation of the phosphorylation of IKK-α/ß and IKß-α. Of note, the production of LPS-induced ROS was reduced by PDA extracts in macrophages, while HO-1 expression, a critical protein of antioxidant signaling pathway, was increased. Based on these results, we proposed a potential mechanism by which degradation products of PDA suppressed inflammation of macrophages via downregulation TLR-4-MYD88-NFκB pathway and simultaneous activation HO-1 pathway, which might be a possible therapeutic target.

Clinical, Laboratory, and Molecular Characteristics and Remission Status in Children With Severe Congenital and Non-congenital Neutropenia.

Objectives: Severe congenital neutropenia (SCN) is a primary immunodeficiency disease characterized by the early onset of recurrent infections and persistent severe neutropenia, with or without genetic defect. We aimed to study the different clinical features and hematological and bone marrow characteristics of patients with SCN and the non-congenital form of severe neutropenia (SN) with unknown etiology. Methods: Thirty-nine Chinese children with severe neutropenia for longer than 6 months unrelated to virus infection or autoimmune diseases were enrolled in the study to analyse the clinical, laboratory, and molecular characteristics. They were followed clinically to observe their remission status. Results: Seven patients were found to have SCN mutations, including ELANE and G6PC3. Among 26 patients with close follow-up, one died for an unknown reason, and 10 resolved spontaneously with a median neutropenia duration of 14.5 months; these patients were designated as having recovered SN. The demographic characteristics of both groups were similar, with a median infection rate of 5 times/year. SCN patients had more frequent infection than recovered SN patients (4 times/year, P = 0.039). The median absolute neutrophil count (ANC) was 0.40 × 109/L in SCN patients, which was significantly higher than 0.2 × 109/L in SN with unknown etiology and 0.21 × 109/L in recovered SN patients (P = 0.021, P = 0.017). The median monocyte count was 1.60 × 109/L in SCN patients, which was also significantly higher than 0.57 × 109/L in SN of unknown etiology and 0.55 × 109/L in recovered SN patients (P = 0.018, P = 0.001). Bone marrow examinations demonstrated myeloid maturation arrest at the myelocyte-metamyelocyte stage in SCN patients and normal findings in SN with unknown etiology and recovered SN patients. Conclusions: Patients with severe neutropenia due to gene mutations demonstrate more serious symptoms than patients with unknown etiology. Patients with relatively higher ANC and monocyte counts are more likely to have known gene mutations. Future studies should focus on more detailed laboratory investigation, prolonged follow-up and advanced molecular biology tools to facilitate accurate diagnosis and effective treatment.

Clinical Manifestations and Genetic Analysis of 17 Patients with Autosomal Dominant Hyper-IgE Syndrome in Mainland China: New Reports and a Literature Review.

PURPOSE: Autosomal dominant hyper-IgE syndrome (AD-HIES) is a rare complicated primary immunodeficiency disease (PID). Signal transducer and activator of transcription 3 (STAT3) gene mutation is found to cause AD-HIES. The distribution of AD-HIES patients with STAT3 deficiency in the Chinese population is not clear. Herein, we retrospectively report 17 AD-HIES patients with STAT3 deficiency and demonstrate their clinical, immunological, and genetic features. METHODS: Patients' clinical data were collected from their medical records. Routine laboratory testing results included lymphocyte subset analysis and immunoglobulin quantification. STAT3 mutations were investigated by sequencing of genomic DNA. RESULTS: Among 575 patients with PID, 28 (4.87%) were clinically diagnosed as HIES. Among them, 17 (2.96%) were confirmed as STAT3 mutant AD-HIES. The ratio of male to female patients was 8:9. All of the 17 patients had NIH scores over 40 points. The mean ages at onset and diagnosis were 1.05 and 10.35 years, respectively. Three patients (17.65%, 3/17) died with a mean age of 13.33 years. Eczema, recurrent skin infection, and respiratory tract infection were the most common clinical symptoms and are present in all of the 17 patients in this study. Six patients (37.5%, 6/16) suffered complication from BCG vaccination. Noninfection symptoms are characteristic facial features in 17 patients (100%, 17/17), retention of primary teeth in 10 patients (90.91%, 10/11), and abnormal bone fractures in 7 patients (41.18%, 7/17). Eleven types of STAT3 mutations were identified in 17 patients, including 1 novel mutation. CONCLUSIONS: We here retrospectively report the largest Chinese cohort of AD-HIES patients with STAT3 mutation. Unique features, when compared to existing literature reports, include (1) later age of diagnosis, (2) significantly higher rate of BCG complications, and (3) lower rate of candidiasis and chronic otitis media.