Single-cell integration reveals metaplasia in inflammatory gut diseases.

The gastrointestinal tract is a multi-organ system crucial for efficient nutrient uptake and barrier immunity. Advances in genomics and a surge in gastrointestinal diseases has fuelled efforts to catalogue cells constituting gastrointestinal tissues in health and disease. Here we present systematic integration of 25 single-cell RNA sequencing datasets spanning the entire healthy gastrointestinal tract in development and in adulthood.

Bin2cell reconstructs cells from high resolution Visium HD data.

Summary: Visium HD by 10X Genomics is the first commercially available platform capable of capturing full scale transcriptomic data paired with a reference morphology image from archived FFPE blocks at sub-cellular resolution. However, aggregation of capture regions to single cells poses challenges. Bin2cell reconstructs cells from the highest resolution data (2 μm bins) by leveraging morphology image segmentation and gene expression information.

Quartz Crystal Microbalance Platform for SARS-CoV-2 Immuno-Diagnostics.

Rapid and accurate serological analysis of SARS-CoV-2 antibodies is important for assessing immune protection from vaccination or infection of individuals and for projecting virus spread within a population. The quartz crystal microbalance (QCM) is a label-free flow-based sensor platform that offers an opportunity to detect the binding of a fluid-phase ligand to an immobilized target molecule in real time. A QCM-based assay was developed for the detection of SARS-CoV-2 antibody binding and evaluated for assay reproducibility.

Cytosolic antibody receptor TRIM21 is required for effective tau immunotherapy in mouse models.

Aggregates of the protein tau are proposed to drive pathogenesis in neurodegenerative diseases. Tau can be targeted by using passively transferred antibodies (Abs), but the mechanisms of Ab protection are incompletely understood. In this work, we used a variety of cell and animal model systems and showed that the cytosolic Ab receptor and E3 ligase TRIM21 (T21) could play a role in Ab protection against tau pathology.

Pitfalls in complement analysis: A systematic literature review of assessing complement activation.

Background: The complement system is an essential component of our innate defense and plays a vital role in the pathogenesis of many diseases. Assessment of complement activation is critical in monitoring both disease progression and response to therapy. Complement analysis requires accurate and standardized sampling and assay procedures, which has proven to be challenging.

Complement Is Activated During Normothermic Machine Perfusion of Porcine and Human Discarded Kidneys.

Background: The gap between demand and supply of kidneys for transplantation necessitates the use of kidneys from extended criteria donors. Transplantation of these donor kidneys is associated with inferior results, reflected by an increased risk of delayed graft function. Inferior results might be explained by the higher immunogenicity of extended criteria donor kidneys.

Autologous stem cell transplantation (ASCT) for acute myeloid leukemia in patients in first complete remission after one versus two induction courses: A study from the ALWP of the EBMT.

Background: Achieving complete remission (CR) is the main goal in AML treatment and a prerequisite for successful autologous stem cell transplantation (ACT).

Methods: Comparing results of peripheral blood ACT in patients with AML in CR1 attained following 1 versus 2 chemotherapy courses transplanted in 2000-2019.

Results: Patients 1532 (84%) with one and 293 (16%) patients with two induction chemotherapies courses (a total of 1825 patients) were included in the study.

Thrombin Differentially Modulates the Acute Inflammatory Response to and in Human Whole Blood.

Thrombin plays a central role in thromboinflammatory responses, but its activity is blocked in the common ex vivo human whole blood models, making an ex vivo study of thrombin effects on thromboinflammatory responses unfeasible. In this study, we exploited the anticoagulant peptide Gly-Pro-Arg-Pro (GPRP) that blocks fibrin polymerization to study the effects of thrombin on acute inflammation in response to and Human blood was anticoagulated with either GPRP or the thrombin inhibitor lepirudin and incubated with either or for up to 4 h at 37°C. In GPRP-anticoagulated blood, there were spontaneous elevations in thrombin levels and platelet activation, which further increased in the presence of bacteria.

Targeting Xcr1 on Dendritic Cells Rapidly Induce Th1-Associated Immune Responses That Contribute to Protection Against Influenza Infection.

Targeting antigen to conventional dendritic cells (cDCs) can improve antigen-specific immune responses and additionally be used to influence the polarization of the immune responses. However, the mechanisms by which this is achieved are less clear. To improve our understanding, we here evaluate molecular and cellular requirements for CD4 T cell and antibody polarization after immunization with Xcl1-fusion vaccines that specifically target cDC1s.

Calprotectin Expressing Donor-Derived Macrophages Increase in Acute Gastrointestinal Graft-Versus-Host Disease.

Acute graft versus host disease (GVHD) is a major cause of morbidity and mortality in allogeneic hematopoietic stem cell transplantation (allo-HSCT). GVHD is therefore the main obstacle for a more widespread use of this highly effective and potentially curative therapy. Although donor T cells are believed to be key mediators in the pathogenesis of acute GVHD, recent reports have suggested that monocyte-derived macrophages also contribute.

Structural basis of T cell receptor specificity and cross-reactivity of two HLA-DQ2.5-restricted gluten epitopes in celiac disease.

Celiac disease is a T cell-mediated chronic inflammatory condition often characterized by human leukocyte antigen (HLA)-DQ2.5 molecules presenting gluten epitopes derived from wheat, barley, and rye. Although some T cells exhibit cross-reactivity toward distinct gluten epitopes, the structural basis underpinning such cross-reactivity is unclear.

TCRpower: quantifying the detection power of T-cell receptor sequencing with a novel computational pipeline calibrated by spike-in sequences.

T-cell receptor (TCR) sequencing has enabled the development of innovative diagnostic tests for cancers, autoimmune diseases and other applications. However, the rarity of many T-cell clonotypes presents a detection challenge, which may lead to misdiagnosis if diagnostically relevant TCRs remain undetected. To address this issue, we developed TCRpower, a novel computational pipeline for quantifying the statistical detection power of TCR sequencing methods.

Intranasal delivery of a cDC1 targeted influenza vaccine with poly(I:C) enhances T cell responses and protects against influenza infection.

Targeting antigens to dendritic cells represent a promising method for enhancing immune responses against specific antigens. However, many studies have focused on systemic delivery (intravenous or intraperitoneally) of targeted antigen, approaches that are not easily transferable to humans. Here we evaluate the efficacy of an influenza vaccine targeting Xcr1 cDC1 administered by intranasal immunization.

Plasma extracellular vesicles in people living with HIV and type 2 diabetes are related to microbial translocation and cardiovascular risk.

HIV and type 2 diabetes (T2D) are both associated with gut microbiota alterations, low-grade endotoxemia and increased cardiovascular risk. We investigated the potential role of plasma extracellular vesicles (EVs) in relation to these processes. Plasma EVs were isolated by size exclusion chromatography in fasting individuals with HIV and T2D (n = 16), T2D only (n = 14), HIV only (n = 20) or healthy controls (n = 19), and characterized by transmission electron microscopy, western blot, nanoparticle tracking analysis and quantitative proteomics.

A high-affinity human TCR-like antibody detects celiac disease gluten peptide-MHC complexes and inhibits T cell activation.

Antibodies specific for peptides bound to human leukocyte antigen (HLA) molecules are valuable tools for studies of antigen presentation and may have therapeutic potential. Here, we generated human T cell receptor (TCR)-like antibodies toward the immunodominant signature gluten epitope DQ2.5-glia-α2 in celiac disease (CeD).

A Conformational Change of Complement C5 Is Required for Thrombin-Mediated Cleavage, Revealed by a Novel Ex Vivo Human Whole Blood Model Preserving Full Thrombin Activity.

Thrombin activation of C5 connects thrombosis to inflammation. Complement research in whole blood ex vivo necessitates anticoagulation, which potentially interferes with the inflammatory modulation by thrombin. We challenged the concept of thrombin as an activator of native C5 by analyzing complement activation and C5 cleavage in human whole blood anticoagulated with Gly-Pro-Arg-Pro (GPRP), a peptide targeting fibrin polymerization downstream of thrombin, allowing complete endogenous thrombin generation.

Integration of T helper and BCR signals governs enhanced plasma cell differentiation of memory B cells by regulation of CD45 phosphatase activity.

Humoral immunity relies on the efficient differentiation of memory B cells (MBCs) into antibody-secreting cells (ASCs). T helper (Th) signals upregulate B cell receptor (BCR) signaling by potentiating Src family kinases through increasing CD45 phosphatase activity (CD45 PA). In this study, we show that high CD45 PA in MBCs enhances BCR signaling and is essential for their effective ASC differentiation.

COVID-19 and its effects on endothelium in HIV-positive patients in sub-Saharan Africa: Cardiometabolic risk, thrombosis and vascular function (ENDOCOVID STUDY).

Background: COVID-19 has affected almost every country in the world, especially in terms of health system capacity and economic burden. People from sub-Saharan Africa (SSA) often face interaction between human immunodeficiency virus (HIV) infection and non-communicable diseases such as cardiovascular disease. Role of HIV infection and anti-retroviral treatment (ART) in altered cardiovascular risk is questionable and there is still need to further carry out research in this field.

Half-life extension of efficiently produced DARPin serum albumin fusions as a function of FcRn affinity and recycling.

Serum albumin shows slow clearance from circulation due to neonatal Fc receptor (FcRn)-mediated recycling and has been used for half-life extension. We report here fusions to a high-affinity DARPin, binding to Epithelial Cell Adhesion Molecule (EpCAM). We developed a novel, efficient expression system for such fusion proteins in Pichia pastoris with titers above 300 mg/L of lab-scale shake-flask culture.

Fusion of engineered albumin with factor IX Padua extends half-life and improves coagulant activity.

The short half-life of coagulation factor IX (FIX) for haemophilia B (HB) therapy has been prolonged through fusion with human serum albumin (HSA), which drives the neonatal Fc receptor (FcRn)-mediated recycling of the chimera. However, patients would greatly benefit from further FIX-HSA half-life extension. In the present study, we designed a FIX-HSA variant through the engineering of both fusion partners.

Comprehensive Analysis of CDR3 Sequences in Gluten-Specific T-Cell Receptors Reveals a Dominant R-Motif and Several New Minor Motifs.

Gluten-specific CD4+ T cells are drivers of celiac disease (CeD). Previous studies of gluten-specific T-cell receptor (TCR) repertoires have found public TCRs shared across multiple individuals, biased usage of particular V-genes and conserved CDR3 motifs. The CDR3 motifs within the gluten-specific TCR repertoire, however, have not been systematically investigated.

Quantification of Porcine Complement Activation Fragment C3a by a Neoepitope-Based Enzyme-Linked Immunosorbent Assay.

Enzyme-linked immunosorbent assay (ELISA) enables fast and simple quantification of analytes in the pico- to nanogram range in complex samples. Here, we describe an ELISA for the detection of porcine C3a as a marker for complement activation. Antibody specificity is critical for a robust assay.

Circulating CD103 γδ and CD8 T cells are clonally shared with tissue-resident intraepithelial lymphocytes in celiac disease.

Gut intraepithelial γδ and CD8 αβ T lymphocytes have been connected to celiac disease (CeD) pathogenesis. Based on the previous observation that activated (CD38), gut-homing (CD103) γδ and CD8 αβ T cells increase in blood upon oral gluten challenge, we wanted to shed light on the pathogenic involvement of these T cells by examining the clonal relationship between cells of blood and gut during gluten exposure. Of 20 gluten-challenged CeD patients, 8 and 10 had increase in (CD38CD103) γδ and CD8 αβ T cells, respectively, while 16 had increase in gluten-specific CD4 T cells.

In Well-Treated Celiac Patients Low-Level Mucosal Inflammation Predicts Response to 14-day Gluten Challenge.

In celiac disease (CeD), gluten activates adaptive immune cells that cause damage to the small intestinal mucosa. Histological evaluation of intestinal biopsies allows for grading of disease severity. CeD can effectively be treated with a life-long gluten-free diet.

Single-cell TCR repertoire analysis reveals highly polyclonal composition of human intraepithelial CD8 αβ T lymphocytes in untreated celiac disease.

We compared the αβ T-cell receptor repertoires of CD8 αβ intraepithelial lymphocytes from celiac disease patients and healthy subjects by single-cell sequencing. We demonstrate that the repertoires of untreated celiac disease patients were more polyclonal and more diverse than what was observed in both treated patients and healthy subjects.