Immunomolecular and reactivity landscapes of gut IgA subclasses in homeostasis and inflammatory bowel disease.

The human gut includes plasma cells (PCs) expressing immunoglobulin A1 (IgA1) or IgA2, two structurally distinct IgA subclasses with elusive regulation, function, and reactivity. We show here that intestinal IgA1+ and IgA2+ PCs co-emerged early in life, comparably accumulated somatic mutations, and were enriched within short-lived CD19+ and long-lived CD19- PC subsets, respectively. IgA2+ PCs were extensively clonally related to IgA1+ PCs and a subset of them presumably emerged from IgA1+ precursors.

Albumin reprograms the B cell transcriptional landscape and improves neutrophil antimicrobial function in patients with decompensated cirrhosis.

Background & Aims: Patients with acutely decompensated (AD) cirrhosis are immunocompromised and particularly susceptible to infections. This study investigated the immunomodulatory actions of albumin by which this protein may lower the incidence of infections.

Methods: Blood immunophenotyping was performed in 11 patients with AD cirrhosis and 10 healthy volunteers (HV).

Women in STEM becoming independent: Embrace failures as part of the journey to success.

This year at , we are highlighting women in science by sharing their stories and amplifying their voices. In this Viewpoint, we hear from a cross section of women, across multiple research fields, discussing their science and the process of setting up a lab as an independent researcher.

Vaccination with staphylococcal protein A protects mice against systemic complications of skin infection recurrences.

Skin and soft tissue infections (SSTIs) are the most common diseases caused by (), which can progress to threatening conditions due to recurrences and systemic complications. Staphylococcal protein A (SpA) is an immunomodulator antigen of , which allows bacterial evasion from the immune system by interfering with different types of immune responses to pathogen antigens. Immunization with SpA could potentially unmask the pathogen to the immune system, leading to the production of antibodies that can protect from a second encounter with , as it occurs in skin infection recurrences.

A monoclonal antibody targeting a large surface of the receptor binding motif shows pan-neutralizing SARS-CoV-2 activity.

Here we report the characterization of 17T2, a SARS-CoV-2 pan-neutralizing human monoclonal antibody isolated from a COVID-19 convalescent individual infected during the first pandemic wave. 17T2 is a class 1 VH1-58/κ3-20 antibody, derived from a receptor binding domain (RBD)-specific IgA memory B cell, with a broad neutralizing activity against former and new SARS-CoV-2 variants, including XBB.1.

Functional characterization of the gonococcal polyphosphate pseudo-capsule.

Neisseria gonorrhoeae is an exclusively human pathogen able to evade the host immune system through multiple mechanisms. Gonococci accumulate a large portion of phosphate moieties as polyphosphate (polyP) on the exterior of the cell. Although its polyanionic nature has suggested that it may form a protective shield on the cell surface, its role remains controversial.

IgTreeZ, A Toolkit for Immunoglobulin Gene Lineage Tree-Based Analysis, Reveals CDR3s Are Crucial for Selection Analysis.

Somatic hypermutation (SHM) is an important diversification mechanism that plays a part in the creation of immune memory. Immunoglobulin (Ig) variable region gene lineage trees were used over the last four decades to model SHM and the selection mechanisms operating on B cell clones. We hereby present IgTreeZ (Immunoglobulin Tree analyZer), a python-based tool that analyses many aspects of Ig gene lineage trees and their repertoires.

Inequality in the middle of a crisis: an analysis of health workers during the COVID-19 pandemic from the profession, race, and gender perspectives.

Studies show that people in vulnerable conditions and some social groups such as women and black people have suffered more intensely from the COVID-19 pandemic impacts. This expression of inequality also manifests itself among healthcare workers, with greater exposure of some specific groups. This paper analyzes the effect of COVID-19 on health care workers and the working conditions in the Brazilian public health system, analyzed from professional, gender, and race perspectives.

Caffeic Acid-Grafted PLGA as a Novel Material for the Design of Fluvastatin-Eluting Nanoparticles for the Prevention of Neointimal Hyperplasia.

Drug-eluting nanoparticles (NPs) administered by an eluting balloon represent a novel tool to prevent restenosis after angioplasty, even if the selection of the suitable drug and biodegradable material is still a matter of debate. Herein, we provide the proof of concept of the use of a novel material obtained by combining the grafting of caffeic acid or resveratrol on a poly(lactide--glycolide) backbone (-CA-PLGA or -RV-PLGA) and the pleiotropic effects of fluvastatin chosen because of its low lipophilic profile which is challenging for the encapsulation in NPs and delivery to the artery wall cells. NPs made of such materials are biocompatible with macrophages, human smooth muscle cells (SMCs), and endothelial cells (ECs).

COVID-19 mRNA Vaccines Preserve Immunogenicity after Re-Freezing.

The massive COVID-19 vaccine purchases made by high-income countries have resulted in important sample losses, mainly due to the complexity of their handling. Here, we evaluated the possibility of preserving the immunogenicity of COVID-19 mRNA vaccines after re-freezing vials, following the extraction of the maximum possible number of samples, as an alternative approach to minimizing their wastage. Thus, we exposed the vaccine vials to different re-freezing conditions and evaluated mRNA integrity and the effects in mice after in vivo administration.

Ulcerative colitis is characterized by a plasmablast-skewed humoral response associated with disease activity.

B cells, which are critical for intestinal homeostasis, remain understudied in ulcerative colitis (UC). In this study, we recruited three cohorts of patients with UC (primary cohort, n = 145; validation cohort 1, n = 664; and validation cohort 2, n = 143) to comprehensively define the landscape of B cells during UC-associated intestinal inflammation. Using single-cell RNA sequencing, single-cell IgH gene sequencing and protein-level validation, we mapped the compositional, transcriptional and clonotypic landscape of mucosal and circulating B cells.

Single-cell analysis of human non-small cell lung cancer lesions refines tumor classification and patient stratification.

Immunotherapy is a mainstay of non-small cell lung cancer (NSCLC) management. While tumor mutational burden (TMB) correlates with response to immunotherapy, little is known about the relationship between the baseline immune response and tumor genotype. Using single-cell RNA sequencing, we profiled 361,929 cells from 35 early-stage NSCLC lesions.

The mRNA-1273 Vaccine Induces Cross-Variant Antibody Responses to SARS-CoV-2 With Distinct Profiles in Individuals With or Without Pre-Existing Immunity.

mRNA-based vaccines effectively induce protective neutralizing antibodies against SARS-CoV-2, the etiological agent of COVID-19. Yet, the kinetics and compositional patterns of vaccine-induced antibody responses to the original strain and emerging variants of concern remain largely unknown. Here we characterized serum antibody classes and subclasses targeting the spike receptor-binding domain of SARS-CoV-2 wild type and α, β, γ and δ variants in a longitudinal cohort of SARS-CoV-2 naïve and COVID-19 recovered individuals receiving the mRNA-1273 vaccine.

SARS-CoV-2 sculpts the immune system to induce sustained virus-specific naïve-like and memory B-cell responses.

Objectives: SARS-CoV-2 infection induces virus-reactive memory B cells expressing unmutated antibodies, which hints at their emergence from naïve B cells. Yet, the dynamics of virus-specific naïve B cells and their impact on immunity and immunopathology remain unclear.

Methods: We longitudinally profiled SARS-CoV-2-specific B-cell responses in 25 moderate-to-severe COVID-19 patients by high-dimensional flow cytometry and isotyping and subtyping ELISA.

Characterization of human FDCs reveals regulation of T cells and antigen presentation to B cells.

Stromal-derived follicular dendritic cells (FDCs) are essential for germinal centers (GCs), the site where B cells maturate their antibodies. FDCs present native antigen to B cells and maintain a CXCL13 gradient to form the B cell follicle. Yet despite their essential role, the transcriptome of human FDCs remains undefined.

Ball-Milling-Enabled Reactivity of Manganese Metal*.

Efforts to generate organomanganese reagents under ball-milling conditions have led to the serendipitous discovery that manganese metal can mediate the reductive dimerization of arylidene malonates. The newly uncovered process has been optimized and its mechanism explored using CV measurements, radical trapping experiments, EPR spectroscopy, and solution control reactions. This unique reactivity can also be translated to solution whereupon pre-milling of the manganese is required.

Ustekinumab in Crohn's disease: Real-world outcomes from the Sicilian network for inflammatory bowel diseases.

Background And Aim: Ustekinumab is approved in Europe for the treatment of moderate to severe Crohn's disease (CD). Italian real-life data are scarce, so the aim of this study was to assess the effectiveness and safety of ustekinumab in an Italian cohort of CD patients.

Methods: Data of patients with CD who started using ustekinumab were extracted from the cohort of the Sicilian Network for Inflammatory Bowel Disease.

Effectiveness of Ustekinumab on Crohn's Disease Associated Spondyloarthropathy: Real-World Data from the Sicilian Network for Inflammatory Bowel Diseases (SN-IBD).

Background: The effectiveness of Ustekinumab (UST) on Crohn's disease (CD)-associated spondyloarthropathy (SpA) is currently unknown.

Research Design And Methods: All consecutive CD patients with active SpA at the initiation of the treatment with UST were extracted from the cohort of the Sicilian Network for Inflammatory Bowel Diseases (SN-IBD). The primary outcome was the articular response at 8 and 24 weeks, defined as the disappearance of objective signs of arthritis (swelling and/or articular stiffness) and resolution of pain.

Gut T cell-independent IgA responses to commensal bacteria require engagement of the TACI receptor on B cells.

The gut mounts secretory immunoglobulin A (SIgA) responses to commensal bacteria through nonredundant T cell-dependent (TD) and T cell-independent (TI) pathways that promote the establishment of mutualistic host-microbiota interactions. SIgAs from the TD pathway target penetrant bacteria, and their induction requires engagement of CD40 on B cells by CD40 ligand on T follicular helper cells. In contrast, SIgAs from the TI pathway bind a larger spectrum of bacteria, but the mechanism underpinning their production remains elusive.

A propensity score weighted comparison of Vedolizumab, Adalimumab, and Golimumab in patients with ulcerative colitis.

Background: No real-life study on the comparative effectiveness of Vedolizumab (VDZ), Adalimumab (ADA), and Golimumab (GOL) in ulcerative colitis (UC) is currently available.

Aims: To compare the effectiveness of the three biologics in consecutive patients with UC.

Methods: A three-arms propensity score-adjusted analysis was performed using the Inverse Probability of Treatment Weighting method.

IgA Summons IgG to Take a Hit at HIV-1.

In this issue of Cell Host & Microbe, Jia et al. used a vesicular stomatitis virus-based probe to isolate B cells expressing broadly neutralizing HIV-1 antibodies. Besides identifying neutralizing epitopes, this study highlights potential protection afforded by IgA arising from either direct IgM-to-IgA or sequential IgM-to-IgG-to-IgA class switching.

Persistence on Anti-Tumour Necrosis Factor Therapy in Older Patients with Inflammatory Bowel Disease Compared with Younger Patients: Data from the Sicilian Network for Inflammatory Bowel Diseases (SN-IBD).

Background And Objective: Older people with inflammatory bowel disease (IBD) appear to have a lower response to anti-tumour necrosis factor (TNF) therapy, with more frequent complications than younger patients. The objective of this study was to assess persistence on therapy and the safety of anti-TNF therapy in older patients (aged ≥ 60 years).

Methods: We retrospectively reviewed the database of the Sicilian Network for Inflammatory Bowel Diseases (SN-IBD), extracting data regarding IBD patients aged ≥ 60 years and controls < 60 years of age at their first course of anti-TNF treatment.