B Cell Development and Maturation

Unraveling pancreatic ductal adenocarcinoma immune prognostic signature through a naive B cell gene set

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC), a leading cause of cancer mortality, has a complex pathogenesis involving various immune cells, including B cells and their subpopulations. Despite emerging research on the role of these cells within the tumor microenvironment (TME), the detailed molecular interactions with tumor-infiltrating immune cells (TIICs) are not fully understood.

METHODS

We applied CIBERSORT to quantify TIICs and naive B cells, which are prognostic for PDAC. Marker genes from scRNA-seq and modular genes from weighted gene co-expression network analysis (WGCNA) were integrated to identify naive B cell-related genes. A prognostic signature was constructed utilizing ten machine-learning algorithms, with validation in external cohorts. We further assessed the immune cell diversity, ESTIMATE scores, and immune checkpoint genes (ICGs) between patient groups stratified by risk to clarify the immune landscape in PDAC.

RESULTS

Our analysis identified 994 naive B cell-related genes across single-cell and bulk transcriptomes, with 247 linked to overall survival. We developed a 12-gene prognostic signature using Lasso and plsRcox algorithms, which was confirmed by 10-fold cross-validation and showed robust predictive power in training and real-world cohorts. Notably, we observed substantial differences in immune infiltration between patients with high and low risk.

CONCLUSION

Our study presents a robust prognostic signature that effectively maps the complex immune interactions in PDAC, emphasizing the critical function of naive B cells and suggesting new avenues for immunotherapeutic interventions. This signature has potential clinical applications in personalizing PDAC treatment, enhancing the understanding of immune dynamics, and guiding immunotherapy strategies.

Effects of porcine epidemic diarrhea virus infection on CD21+ B cells activation

Porcine epidemic diarrhea virus (PEDV) is a devastating pathogen of acute- gastrointestinal infectious diseases, which can cause vomiting, diarrhea, dehydration and high morbidity and mortality among neonatal piglets. Humoral immunity plays a vital role in the host anti-PEDV infection process, but the mechanism of PEDV-induced B-cell immune response remains unknown. In this study, the effects of PEDV infection on CD21+ B cell activation were systematically analyzed through animal experiments. Enzyme-linked immunosorbent assays (ELISA) revealed that low levels of serum-specific IgA, IgM, or IgG were detected in piglets after PEDV infection, respectively. Serum interleukin (IL)-6 levels increased significantly at 4 d after infection, and the levels of IL-4, B-cell activating factor (BAFF), interferon (IFN)-γ, transforming growth factor (TGF)-β and IL-10 decreased at 7 d after infection. Fluorescence-activated cell sorting (FACS) showed that expression levels of CD21, MHC Ⅱ, CD40, and CD38 on B cell surfaces were significantly higher. In contrast, the proportions of CD21+IgM+ B cells were decreased in peripheral blood mononuclear cells (PBMCs) from the infected piglets. No differences were found in the percentage of CD21+CD80+ and CD21+CD27+ B cells in PBMCs from the infected piglets. In addition, the number of CD21+B cells in PBMCs stimulated with PEDV in vitro was significantly lower. No significant change in the mRNA expression of BCR molecules was found while the expression levels of paired immunoglobulin-like receptor B (PIR-B), B cell adaptor molecule of 32 kDa (Bam32) and BAFF were decreased. In conclusion, our research demonstrates that virulent strains of PEDV profoundly impact B cell activation, leading to alterations in phenotypic expression and BCR signaling molecules. Furthermore, this dysregulation results in compromised specific antibody secretion and perturbed cytokine production, highlighting the intricate immunological dysfunctions induced by PEDV infection.

B cells and atherosclerosis: A HIV perspective

Atherosclerosis remains a leading cause of cardiovascular disease (CVD) globally, with the complex interplay of inflammation and lipid metabolism at its core. Recent evidence suggests a role of B cells in the pathogenesis of atherosclerosis; however, this relationship remains poorly understood, particularly in the context of HIV. We review the multifaceted functions of B cells in atherosclerosis, with a specific focus on HIV. Unique to atherosclerosis is the pivotal role of natural antibodies, particularly those targeting oxidized epitopes abundant in modified lipoproteins and cellular debris. B cells can exert control over cellular immune responses within atherosclerotic arteries through antigen presentation, chemokine production, cytokine production, and cell-cell interactions, actively participating in local and systemic immune responses. We explore how HIV, characterized by chronic immune activation and dysregulation, influences B cells in the context of atherosclerosis, potentially exacerbating CVD risk in persons with HIV. By examining the proatherogenic and antiatherogenic properties of B cells, we aim to deepen our understanding of how B cells influence atherosclerotic plaque development, especially within the framework of HIV. This research provides a foundation for novel B cell-targeted interventions, with the potential to mitigate inflammation-driven cardiovascular events, offering new perspectives on CVD risk management in PLWH.

Multidimensional biological characteristics of ground glass nodules

The detection rate of ground glass nodules (GGNs) has increased in recent years because of their malignant potential but relatively indolent biological behavior; thus, correct GGN recognition and management has become a research focus. Many scholars have explored the underlying mechanism of the indolent progression of GGNs from several perspectives, such as pathological type, genomic mutational characteristics, and immune microenvironment. GGNs have different major mutated genes at different stages of development; EGFR mutation is the most common mutation in GGNs, and p53 mutation is the most abundant mutation in the invasive stage of GGNs. Pure GGNs have fewer genomic alterations and a simpler genomic profile and exhibit a gradually evolving genomic mutation profile as the pathology progresses. Compared to advanced lung adenocarcinoma, GGN lung adenocarcinoma has a higher immune cell percentage, is under immune surveillance, and has less immune escape. However, as the pathological progression and solid component increase, negative immune regulation and immune escape increase gradually, and a suppressive immune environment is established gradually. Currently, regular computer tomography monitoring and surgery are the main treatment strategies for persistent GGNs. Stereotactic body radiotherapy and radiofrequency ablation are two local therapeutic alternatives, and systemic therapy has been progressively studied for lung cancer with GGNs. In the present review, we discuss the characterization of the multidimensional molecular evolution of GGNs that could facilitate more precise differentiation of such highly heterogeneous lesions, laying a foundation for the development of more effective individualized treatment plans.

The aging lung: microenvironment, mechanisms, and diseases

With the development of global social economy and the deepening of the aging population, diseases related to aging have received increasing attention. The pathogenesis of many respiratory diseases remains unclear, and lung aging is an independent risk factor for respiratory diseases. The aging mechanism of the lung may be involved in the occurrence and development of respiratory diseases. Aging-induced immune, oxidative stress, inflammation, and telomere changes can directly induce and promote the occurrence and development of lung aging. Meanwhile, the occurrence of lung aging also further aggravates the immune stress and inflammatory response of respiratory diseases; the two mutually affect each other and promote the development of respiratory diseases. Explaining the mechanism and treatment direction of these respiratory diseases from the perspective of lung aging will be a new idea and research field. This review summarizes the changes in pulmonary microenvironment, metabolic mechanisms, and the progression of respiratory diseases associated with aging.

The dynamics of B-cell reconstitution post allogeneic hematopoietic stem cell transplantation: A real-world study

BACKGROUND

The immune reconstitution after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is crucial for preventing infections and relapse and enhancing graft-versus-tumor effects. B cells play an important role in humoral immunity and immune regulation, but their reconstitution after allo-HSCT has not been well studied.

METHODS

In this study, we analyzed the dynamics of B cells in 252 patients who underwent allo-HSCT for 2 years and assessed the impact of factors on B-cell reconstitution and their correlations with survival outcomes, as well as the development stages of B cells in the bone marrow and the subsets in the peripheral blood.

RESULTS

We found that the B-cell reconstitution in the bone marrow was consistent with the peripheral blood (p = 0.232). B-cell reconstitution was delayed by the male gender, age >50, older donor age, the occurrence of chronic and acute graft-versus-host disease, and the infections of fungi and cytomegalovirus. The survival analysis revealed that patients with lower B cells had higher risks of death and relapse. More importantly, we used propensity score matching to obtain the conclusion that post-1-year B-cell reconstitution is better in females. Meanwhile, using mediation analysis, we proposed the age-B cells-survival axis and found that B-cell reconstitution at month 12 posttransplant mediated the effect of age on patient survival (p = 0.013). We also found that younger patients showed more immature B cells in the bone marrow after transplantation (p = 0.037).

CONCLUSION

Our findings provide valuable insights for optimizing the management of B-cell reconstitution and improving the efficacy and safety of allo-HSCT.

Age-associated accumulation of B cells promotes macrophage inflammation and inhibits lipolysis in adipose tissue during sepsis

Non-canonical lipolysis induced by inflammatory cytokines or Toll-like receptor ligands is required for the regulation of inflammation during endotoxemia and sepsis. Canonical lipolysis induced by catecholamines declines during aging due to factors including an expansion of lymphocytes, pro-inflammatory macrophage polarization, and an increase in chronic low-grade inflammation; however, the extent to which the non-canonical pathway of lipolysis is active and impacted by immune cells during aging remains unclear. Therefore, we aimed to define the extent to which immune cells from old mice influence non-canonical lipolysis during sepsis. We identified age-associated impairments of non-canonical lipolysis and an accumulation of dysfunctional B1 B cells in the visceral white adipose tissue (vWAT) of old mice. Lifelong deficiency of B cells results in restored non-canonical lipolysis and reductions in pro-inflammatory macrophage populations. Our study suggests that targeting the B cell-macrophage signaling axis may resolve metabolic dysfunction in aged vWAT and attenuate septic severity in older individuals.

Comparison of B cells' immune response induced by PEDV virulent and attenuated strains

Porcine epidemic diarrhea virus (PEDV) is an acute, highly contagious enterovirus that infects pigs of all ages. The B cells are important for antigen presentation, antibody production, and cytokine secretion to resist infection. However, the role of B cells in PEDV infection remains unclear. In this study, the effects of PEDV virulent (QY2016) and attenuated strains (CV777) on B cells sorted from neonatal piglets, nursery piglets, and gilts were investigated. The results showed that PEDV-QY2016 and PEDV-CV777 could significantly increase the expression of CD54 and CD27 in B cells from neonatal piglets. The percentages of CD80, MHC II, and IgM expressed on neonatal piglet B cells infected with PEDV-QY2016 were significantly lower than those expressed on the B cells infected with PEDV-CV777. Both PEDV-QY2016 and PEDV-CV777 could stimulate IFN-α and GM-CSF secretions in neonatal piglet B cells; IL-1, IFN-α, and IL-4 secretion in nursery piglet B cells; and IL-1, TGF-β secretion, and GM-CSF in gilt B cells. Furthermore, both PEDV-QY2016 and PEDV-CV777 could induce the secretion of IgA, IgM, and IgG in nursery piglet B cells but could not induce the secretion of IgA, IgM, and IgG in neonatal piglet B cells. The secretion of IgA, IgM, and IgG was significantly higher by the PEDV-CV777 strains infected B cells than those by the PEDV-QY2016 strains infected gilt B cells. In conclusion, the surface molecule expression, cytokine secretion, and antibody production of B cells induced by PEDV are closely related to the ages of pigs and the virulence of the PEDV strain.

CD19/CD20 dual-targeted chimeric antigen receptor-engineered natural killer cells exhibit improved cytotoxicity against acute lymphoblastic leukemia

BACKGROUND

Chimeric antigen receptor natural killer (CAR-NK) cells represent a promising advancement in CAR cell therapy, addressing limitations observed in CAR-T cell therapy. However, our prior study revealed challenges in CAR-NK cells targeting CD19 antigens, as they failed to eliminate CD19+ Raji cells in NSG tumor-bearing mice, noting down-regulation or loss of CD19 antigen expression in some Raji cells. In response, this study aims to enhance CD19 CAR-NK cell efficacy and mitigate the risk of tumor recurrence due to target antigen escape by developing CD19 and CD20 (CD19/CD20) dual-targeted CAR-NK cells.

METHODS

Initially, mRNA encoding anti-CD19 CARs (FMC63 scFv-CD8α-4-1BB-CD3ζ) and anti-CD20 CARs (LEU16 scFv-CD8α-4-1BB-CD3ζ) was constructed via in vitro transcription. Subsequently, CD19/CD20 dual-targeted CAR-NK cells were generated through simultaneous electrotransfection of CD19/CD20 CAR mRNA into umbilical cord blood-derived NK cells (UCB-NK).

RESULTS

Following co-electroporation, the percentage of dual-CAR expression on NK cells was 86.4% ± 1.83%, as determined by flow cytometry. CAR expression was detectable at 8 h post-electric transfer, peaked at 24 h, and remained detectable at 96 h. CD19/CD20 dual-targeted CAR-NK cells exhibited increased specific cytotoxicity against acute lymphoblastic leukemia (ALL) cell lines (BALL-1: CD19+CD20+, REH: CD19+CD20-, Jurkat: CD19-CD20-) compared to UCB-NK, CD19 CAR-NK, and CD20 CAR-NK cells. Moreover, CD19/CD20 dual-targeted CAR-NK cells released elevated levels of perforin, IFN-γ, and IL-15. Multiple activation markers such as CD69 and cytotoxic substances were highly expressed.

CONCLUSIONS

The creation of CD19/CD20 dual-targeted CAR-NK cells addressed the risk of tumor escape due to antigen heterogeneity in ALL, offering efficient and safe 'off-the-shelf' cell products. These cells demonstrate efficacy in targeting CD20 and/or CD19 antigens in ALL, laying an experimental foundation for their application in ALL treatment.

Unleashing the power of antibodies: Engineering for tomorrow's therapy

Antibodies play a crucial role in host defense against various diseases. Antibody engineering is a multidisciplinary field that seeks to improve the quality of life of humans. In the context of disease, antibodies are highly specialized proteins that form a critical line of defense against pathogens and the disease caused by them. These infections trigger the innate arm of immunity by presenting on antigen-presenting cells such as dendritic cells. This ultimately links to the adaptive arm, where antibody production and maturation occur against that particular antigen. Upon binding with their specific antigens, antibodies trigger various immune responses to eliminate pathogens in a process called complement-dependent cytotoxicity and phagocytosis of invading microorganisms by immune cells or induce antibody-dependent cellular cytotoxicity is done by antibodies. These engineered antibodies are being used for various purposes, such as therapeutics, diagnostics, and biotechnology research. Cutting-edge techniques that include hybridoma technology, transgenic mice, display techniques like phage, yeast and ribosome displays, and next-generation sequencing are ways to engineer antibodies and mass production for the use of humankind. Considering the importance of antibodies in protecting from a diverse array of pathogens, investing in research holds great promise to develop future therapeutic targets to combat various diseases.

Anti-CD20 treatment attenuates Th2 cell responses: implications for the role of lung follicular mature B cells in the asthmatic mice

BACKGROUND

B cells were believed to act as antigen-presenting cells (APCs) to promote T helper type 2 (Th2) cell responses. However, the role of lung B cells and its subpopulations in Th2 cell responses in asthma remains unclear.

OBJECTIVE

We leveraged an anti-CD20 monoclonal antibody (mAb) treatment that has been shown to selectively deplete B cells in mice and investigated whether this treatment modulates Th2 cell responses and this modulation is related to lung follicular mature (FM) B cells in a murine model of asthma.

METHODS AND RESULTS

We used a house dust mite (HDM)-induced asthma mouse model and found that anti-CD20 mAb treatment attenuates Th2 cell responses. Meanwhile, anti-CD20 mAb treatment did dramatically reduce the number of B cells, especially FM B cells in the lungs, but did not impact the frequency of other immune cell types, including lung T cells, dendritic cells, natural killer cells, and regulatory T cells in wild-type mice. Moreover, we found that the suppressive effect of anti-CD20 mAb treatment on Th2 cell responses could be reversed upon adoptive transfer of lung FM B cells, but not lung CD19+ B cells without FM B cells in asthmatic mice.

CONCLUSIONS

These findings reveal that anti-CD20 mAb treatment alleviates Th2 cell responses, possibly by depleting lung FM B cells in a Th2-driven asthma model. This implies a potential therapeutic approach for asthma treatment through the targeting of lung FM B cells.

The role of immune system in atherosclerosis: Molecular mechanisms, controversies, and future possibilities

Numerous cardiovascular disorders have atherosclerosis as their pathological underpinning. Numerous studies have demonstrated that, with the aid of pattern recognition receptors, cytokines, and immunoglobulins, innate immunity, represented by monocytes/macrophages, and adaptive immunity, primarily T/B cells, play a critical role in controlling inflammation and abnormal lipid metabolism in atherosclerosis. Additionally, the finding of numerous complement components in atherosclerotic plaques suggests yet again how heavily the immune system controls atherosclerosis. Therefore, it is essential to have a thorough grasp of how the immune system contributes to atherosclerosis. The specific molecular mechanisms involved in the activation of immune cells and immune molecules in atherosclerosis, the controversy surrounding some immune cells in atherosclerosis, and the limitations of extrapolating from relevant animal models to humans were all carefully reviewed in this review from the three perspectives of innate immunity, adaptive immunity, and complement system. This could provide fresh possibilities for atherosclerosis research and treatment in the future.

B cells mediate lung ischemia/reperfusion injury by recruiting classical monocytes via synergistic B cell receptor/TLR4 signaling

Ischemia/reperfusion injury-mediated (IRI-mediated) primary graft dysfunction (PGD) adversely affects both short- and long-term outcomes after lung transplantation, a procedure that remains the only treatment option for patients suffering from end-stage respiratory failure. While B cells are known to regulate adaptive immune responses, their role in lung IRI is not well understood. Here, we demonstrated by intravital imaging that B cells are rapidly recruited to injured lungs, where they extravasate into the parenchyma. Using hilar clamping and transplant models, we observed that lung-infiltrating B cells produce the monocyte chemokine CCL7 in a TLR4-TRIF-dependent fashion, a critical step contributing to classical monocyte (CM) recruitment and subsequent neutrophil extravasation, resulting in worse lung function. We found that synergistic BCR-TLR4 activation on B cells is required for the recruitment of CMs to the injured lung. Finally, we corroborated our findings in reperfused human lungs, in which we observed a correlation between B cell infiltration and CM recruitment after transplantation. This study describes a role for B cells as critical orchestrators of lung IRI. As B cells can be depleted with currently available agents, our study provides a rationale for clinical trials investigating B cell-targeting therapies.

EBF1, PAX5, and MYC: regulation on B cell development and association with hematologic neoplasms

During lymphocyte development, a diverse repertoire of lymphocyte antigen receptors is produced to battle against pathogens, which is the basis of adaptive immunity. The diversity of the lymphocyte antigen receptors arises primarily from recombination-activated gene (RAG) protein-mediated V(D)J rearrangement in early lymphocytes. Furthermore, transcription factors (TFs), such as early B cell factor 1 (EBF1), paired box gene 5 (PAX5), and proto-oncogene myelocytomatosis oncogene (MYC), play critical roles in regulating recombination and maintaining normal B cell development. Therefore, the aberrant expression of these TFs may lead to hematologic neoplasms.

Direct Comparison of the Hinge-Cleaving Proteases IgdE and BdpK for LC-MS-Based IgG1 Clonal Profiling

Human antibodies are heterogeneous molecules primarily due to clonal sequence variations. Analytical techniques to assess antibody levels quantitatively, such as ELISA, lack the power to resolve abundances at the clonal level. Recently, we introduced an LC-MS-based approach that can distinguish and quantify antibody clones using the mass and retention time of their corresponding Fab-fragments. We used specific hinge-cleaving protease IgdE (FabALACTICA) to release the Fab-fragments from the constant Fc region of the antibody. Here, we explore an alternative IgG1 hinge-cleaving protease, BdpK (FabDELLO), and compare it directly to IgdE for use in IgG1 repertoire profiling. We used IgdE and BdpK in parallel to digest all IgG1s from the same set of plasma samples. Both proteases cleave IgG1 specifically in the hinge, albeit via different mechanisms and at two distinct cleavage sites. Notwithstanding these differences, the Fab fragments generated by IgdE or BdpK produced highly similar clonal repertoires. However, IgdE required ∼16 h of incubation to digest plasma IgG1s, while BdpK required ∼2 h. We authenticated the similarity of the clones by top-down proteomics using electron transfer dissociation. We conclude that BdpK performs very well in digesting polyclonal plasma IgG1s and that neither BdpK nor IgdE displays detectable biases in cleaving IgG1s. We anticipate that BdpK may emerge as the preferred protease for IgG1 hinge-digestion because it offers a shorter digestion time compared to IgdE, an equally specific digestion site, and no bias against any IgG1 present in plasma.

Loss of B1 and marginal zone B cells during ovarian cancer

Recent advances in immunotherapy have not addressed the challenge presented by ovarian cancer. Although the peritoneum is an "accessible" locus for this disease there has been limited characterization of the immunobiology therein. We investigated the ID8-C57BL/6J ovarian cancer model and found marked depletion of B1 cells from the ascites of the peritoneal cavity. There was also selective loss of the B1 and marginal zone B cell subsets from the spleen. Immunity to antigens that activate these subsets validated their loss rather than relocation. A marked influx of myeloid-derived suppressor cells correlated with B cell subset depletion. These observations are discussed in the context of the housekeeping burden placed on innate B cells during ovarian cancer and to foster consideration of B cell biology in therapeutic strategies to address this challenge.

Emerging insights into atypical B cells in pediatric chronic infectious diseases and immune system disorders: T(o)-bet on control of B-cell immune activation

Repetitive or persistent cellular stimulation in vivo has been associated with the development of a heterogeneous B-cell population that exhibits a distinctive phenotype and, in addition to classical B-cell markers, often expresses the transcription factor T-bet and myeloid marker CD11c. Research suggests that this atypical population consists of B cells with distinct B-cell receptor specificities capable of binding the antigens responsible for their development. The expansion of this population occurs in the presence of chronic inflammatory conditions and autoimmune diseases where different nomenclatures have been used to describe them. However, as a result of the diverse contexts in which they have been investigated, these cells have remained largely enigmatic, with much ambiguity remaining regarding their phenotype and function in humoral immune response as well as their role in autoimmunity. Atypical B cells have garnered considerable interest because of their ability to produce specific antibodies and/or autoantibodies and because of their association with key disease manifestations. Although they have been widely described in the context of adults, little information is present for children. Therefore, the aim of this narrative review is to describe the characteristics of this population, suggest their function in pediatric immune-related diseases and chronic infections, and explore their potential therapeutic avenues.

Immunophenotypic assessment of clonal plasma cells and B-cells in bone marrow and blood in the diagnostic classification of early stage monoclonal gammopathies: an iSTOPMM study

Monoclonal gammopathy of undetermined significance (MGUS) is the earliest discernible stage of multiple myeloma (MM) and Waldenström's macroglobulinemia (WM). Early diagnosis of MG may be compromised by the low-level infiltration, undetectable to low-sensitive methodologies. Here, we investigated the prevalence and immunophenotypic profile of clonal (c) plasma cells (PC) and/or cB-lymphocytes in bone marrow (BM) and blood of subjects with a serum M-component from the iSTOPMM program, using high-sensitive next-generation flow cytometry (NGF), and its utility in the diagnostic classification of early-stage MG. We studied 164 paired BM and blood samples from 82 subjects, focusing the analysis on: 55 MGUS, 12 smoldering MM (SMM) and 8 smoldering WM (SWM). cPC were detected in 84% of the BM samples and cB-lymphocytes in 45%, coexisting in 39% of cases. In 29% of patients, the phenotypic features of cPC and/or cB-lymphocytes allowed a more accurate disease classification, including: 19/55 (35%) MGUS, 1/12 (8%) SMM and 2/8 (25%) SWM. Blood samples were informative in 49% of the BM-positive cases. We demonstrated the utility of NGF for a more accurate diagnostic classification of early-stage MG.

Genome-wide DNA methylation profiles analysis in primary warm autoimmune hemolytic anemia patients

BACKGROUND

Autoimmune hemolytic anemia (AIHA) is caused by auto-antibodies, secreted by overactivated B cells, directed against self-red blood cells, resulting in hemolysis. It found that aberrant DNA methylation in B cells can induce the production of autoantibodies. Therefore, we attempted to explore if similar aberrant DNA methylation occur in AIHA patients.

METHODS

A 49-year-old female wAIHA patient and a 47-year-old female healthy control (HC) were enrolled. Peripheral blood (PB) B cells DNA was extracted. After constructing genomic libraries, bisulfite genomic sequencing (BSP) and DNA methylation profiles were analyzed. BSP was verified using PB B cells from 10 patients with hemolysis, 10 patients with hemolytic remission, and 10 healthy controls (HCs) by Methylation-specific PCR.

RESULTS

Total DNA methylation of whole-genome C bases (4.8%) and CG type bases (76.8%) in wAIHA patient were lower than those in the HC (5.3 and 82.5%, respectively) (p = 0.022 and p < 0.001). DNA methylation of C bases and CG type bases in whole-genome regulatory elements, such as coding sequence, up2Kb and down2Kb in the patient were also lower than those in the HC (p = 0.041, p = 0.038, and p = 0.029). 30,180 DNA-methylated regions (DMRs) on all 23 chromosomes were identified. DMR-related genes were mainly involved in the Rap1, phospholipase D, HIF-1, calcium, vascular endothelial growth factor (VEGF) and Ras signaling pathways.

CONCLUSION

The DNA methylation spectrum of B cells in AIHA patients is different from that of HC, and the proportion of hypo-methylation regions is higher than that of HC. DMR-related genes are mainly related to some signaling pathways.

Disturbance of Adaptive Immunity System Was Accompanied by a Decrease in Plasma Short-Chain Fatty Acid for Patients Hospitalized During SARS-CoV-2 Infection After COVID-19 Vaccination

Introduction

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can lead to disorders of immune function and a decrease in the diversity of intestinal flora. We aimed to explore the changes of circulating immune cell subsets and the plasma level of intestinal short-chain fatty acids (SCFAs) in patients with Coronavirus disease 2019 (COVID-19), further understanding the pathogenesis of COVID-19.

Methods

The study included 83 newly diagnosed COVID-19 patients and 39 non-COVID-19 controls. All have completed a full course of vaccination against SARS-CoV-2. The levels of peripheral lymphocyte subsets and plasma cytokines were detected by flow cytometry. Targeted metabolomics was used to explore the level of SCFAs in plasma.

Results

Compared with the non-COVID-19 group, COVID-19 patients showed a decrease in CD19+B cells, CD4+T cells, CD8+T cells, NK cells, CD4+CD8+T cells and CD4-CD8-T cells (all p<0.001) and concomitantly an increase in sIL-2R, IL-6 and IL-10 (all p<0.005). These alterations were more pronounced in those critical patients. In addition, COVID-19 patients had lower levels of propanoic acid (PA), butyric acid (BA), isobutyric acid (IBA) and isohexanoic acid (ICA) (all p<0.01). Among them, the level of ICA is positively correlated with the absolute number of immune cells.

Conclusion

Our study suggests the immune cell subsets in COVID-19 patients who had completed vaccination were still severely disturbed and concomitantly lower SCFAs, especially in severe patients with poor prognosis. Lower levels of plasma SCFAs may contribute to lymphopenia in COVID-19. The potential relationship between plasma SCFAs and immune cell reduction provides a new direction for the treatment of COVID-19.

Advances in the study of B cells in renal ischemia-reperfusion injury

Renal ischemia-reperfusion injury (IRI) is a non-negligible clinical challenge for clinicians in surgeries such as renal transplantation. Functional loss of renal tubular epithelial cell (TEC) in IRI leads to the development of acute kidney injury, delayed graft function (DGF), and allograft rejection. The available evidence indicates that cellular oxidative stress, cell death, microvascular dysfunction, and immune response play an important role in the pathogenesis of IRI. A variety of immune cells, including macrophages and T cells, are actively involved in the progression of IRI in the immune response. The role of B cells in IRI has been relatively less studied, but there is a growing body of evidence for the involvement of B cells, which involve in the development of IRI through innate immune responses, adaptive immune responses, and negative immune regulation. Therefore, therapies targeting B cells may be a potential direction to mitigate IRI. In this review, we summarize the current state of research on the role of B cells in IRI, explore the potential effects of different B cell subsets in the pathogenesis of IRI, and discuss possible targets of B cells for therapeutic aim in renal IRI.

Charging CAR by electrostatic power

Chimeric antigen receptor (CAR)-T cell therapy has emerged as a promising approach for cancer treatment. CAR is a synthetic immune receptor that recognizes tumor antigen and activates T cells through multiple signaling pathways. However, the current CAR design is not as robust as T cell receptor (TCR), a natural antigen receptor with high sensitivity and efficiency. TCR signaling relies on specific molecular interactions, and thus electrostatic force, the major force of molecular interactions, play critical roles. Understanding how electrostatic charge regulates TCR/CAR signaling events will facilitate the development of next-generation T cell therapies. This review summarizes recent findings on the roles of electrostatic interactions in both natural and synthetic immune receptor signaling, specifically that in CAR clustering and effector molecule recruitments, and highlights potential strategies for engineering CAR-T cell therapy by leveraging charge-based interactions.

Lipid metabolism in regulation of B cell development and autoimmunity

B cells play an important role in adaptive immunity and participate in the process of humoral immunity mainly by secreting antibodies. The entire development and differentiation process of B cells occurs in multiple microenvironments and is regulated by a variety of environmental factors and immune signals. Differentiation biases or disfunction of B cells participate in the process of many autoimmune diseases. Emerging studies report the impact of altered metabolism in B cell biology, including lipid metabolism. Here, we discuss how extracellular lipid environment and metabolites, membrane lipid-related components, and lipid synthesis and catabolism programs coordinate B cell biology and describe the crosstalk of lipid metabolic programs with signal transduction pathways and transcription factors. We conclude with a summary of therapeutic targets for B cell lipid metabolism and signaling in autoimmune diseases and discuss important future directions.

Host Responses to Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) infections are a constant public health problem, especially in infants and older adults. Virtually all children will have been infected with RSV by the age of two, and reinfections are common throughout life. Since antigenic variation, which is frequently observed among other respiratory viruses such as SARS-CoV-2 or influenza viruses, can only be observed for RSV to a limited extent, reinfections may result from short-term or incomplete immunity. After decades of research, two RSV vaccines were approved to prevent lower respiratory tract infections in older adults. Recently, the FDA approved a vaccine for active vaccination of pregnant women to prevent severe RSV disease in infants during their first RSV season. This review focuses on the host response to RSV infections mediated by epithelial cells as the first physical barrier, followed by responses of the innate and adaptive immune systems. We address possible RSV-mediated immunomodulatory and pathogenic mechanisms during infections and discuss the current vaccine candidates and alternative treatment options.

Serum Paraprotein Is Associated with Adverse Prognostic Factors and Outcome, across Different Subtypes of Mature B-Cell Malignancies-A Systematic Review

The presence of a serum paraprotein (PP) is usually associated with plasma-cell dyscrasias, Waldenstrom Macroglobulinemia/lymphoplasmacytic lymphoma, and cryoglobulinemia. However, PP is also often reported in other high- and low-grade B-cell malignancies. As these reports are sparse and heterogeneous, an overall view on this topic is lacking, Therefore, we carried out a complete literature review to detail the characteristics, and highlight differences and similarities among lymphoma entities associated with PP. In these settings, IgM and IgG are the prevalent PP subtypes, and their serum concentration is often low or even undetectable without immunofixation. The relevance of paraproteinemia and its prevalence, as well as the impact of IgG vs. IgM PP, seems to differ within B-NHL subtypes and CLL. Nonetheless, paraproteinemia is almost always associated with advanced disease, as well as with immunophenotypic, genetic, and clinical features, impacting prognosis. In fact, PP is reported as an independent prognostic marker of poor outcome. All the above call for implementing clinical practice, with the assessment of paraproteinemia, in patients' work-up. Indeed, more studies are needed to shed light on the biological mechanism causing more aggressive disease. Furthermore, the significance of paraproteinemia, in the era of targeted therapies, should be assessed in prospective trials.

Adipokines from adipose tissue and common variable immunodeficiency: Is there any association?

Adiponectin and leptin are adipokines, secreted by white adipose tissue (WAT), which play an important role in energy homeostasis. Some evidence has shown that adipokine-producing adipose cells present in the bone marrow (BM) appear to exert an influence on hematopoiesis and B cell development. Common variable immunodeficiency (CVID) is one of the most common inborn errors of immunity in humans. In CVID, numerical and/or functional defects of B cells and their precursors result in hypogammaglobulinemia, usually Immunoglobulin (Ig) A and IgG. Manifestations of CVID include immunodeficiency, autoimmunity, inflammation and lymphoproliferation, resulting in a wide range of phenotypes. How adipokines interact and influence the pathophysiology of CVID is still unclear. In this review, we seek to summarize the aspects known so far concerning the interface between adipokines, B cells and CVID. More research is needed to fully understand these interactions; this knowledge is a potential avenue for the discovery of useful biomarkers and may provide new therapeutic targets for the treatment of patients with CVID and related diseases.

B cells: The many facets of B cells in allergic diseases

B cells play a key role in our immune system through their ability to produce antibodies, suppress a proinflammatory state, and contribute to central immune tolerance. We aim to provide an in-depth knowledge of the molecular biology of B cells, including their origin, developmental process, types and subsets, and functions. In allergic diseases, B cells are well known to induce and maintain immune tolerance through the production of suppressor cytokines such as IL-10. Similarly, B cells protect against viral infections such as severe acute respiratory syndrome coronavirus 2 that caused the recent coronavirus disease 2019 pandemic. Considering the unique and multifaceted functions of B cells, we hereby provide a comprehensive overview of the current knowledge of B-cell biology and its clinical applications in allergic diseases, organ transplantation, and cancer.

Interleukin 6 exacerbates the progression of warm autoimmune hemolytic anemia by influencing the activity and function of B cells

To explore the effect of IL-6 on the activity and secretory function of B cells and analyze its effect on clinical indicators and efficacy in wAIHA patients. This study included 25 hemolytic wAIHA patients, 13 remission patients, and 10 HCs. Plasma levels of various cytokines were detected using CBA. PBMCs were extracted from 12 hemolytic wAIHA patients and divided into three wells, stimulation with IL-6 and IL-6 + tocilizumab, the blank control wells were also set. After 48 h of in vitro cell culture, percentage of CD5+CD80+, CD5-CD80+,CD5+CD86+,CD5-CD86+,CD5+IL-10+,CD5-IL-10+B cells were determined by flow-cytometry. Plasma levels of IL-6 and IL-10 in hemolytic episode group were significantly higher than that in HCs group (p = 0.0243; p = 0.0214). RBC and Hb levels were negatively correlated with IL-6 levels in wAIHA patients, while LDH levels were positively correlated.Therapeutic effects of glucocorticoid and duration of efficacy were also significantly correlated with IL-6 levels in wAIHA patients. After 48 h in vitro cell culture, percentages of CD80+/CD5+CD19+and CD80+/CD5-CD19+ cells in the IL-6 stimulation group were higher than those in blank control group (p = 0.0019; p = 0.0004), while CD86+/CD5+ CD19+ and CD86+/CD5-CD19+ cells were not statistically different before and after IL-6 stimulation. Percentage of IL-10+/CD5+ CD19+ cells in IL-6 stimulation group was lower than that in blank control (p = 0.0017) and IL-6 + toc (p = 0.0117) group. Percentage of IL-10+/CD5- CD19+cells in the IL-6 stimulation group was lower than that in the blank control group (p = 0.0223). Plasma levels of IL-6 were significantly elevated in hemolytic wAIHA patients and correlated with clinical indicators and efficacy. IL-6 promotes the activation of B cells. Although the results were not statistically significant, IL-6R antagonist tocilizumab may hopefully become a targeted therapy for wAIHA patients.

The Molecular Role of Immune Cells in Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is a rare and severe condition characterized by chamber dilation and impaired contraction of the left ventricle. It constitutes a fundamental etiology for profound heart failure and abrupt cardiac demise, rendering it a prominent clinical indication for heart transplantation (HTx) among both adult and pediatric populations. DCM arises from various etiologies, including genetic variants, epigenetic disorders, infectious insults, autoimmune diseases, and cardiac conduction abnormalities. The maintenance of cardiac function involves two distinct types of immune cells: resident immune cells and recruited immune cells. Resident immune cells play a crucial role in establishing a harmonious microenvironment within the cardiac tissue. Nevertheless, in response to injury, cardiomyocytes initiate a cytokine cascade that attracts peripheral immune cells, thus perturbing this intricate equilibrium and actively participating in the initiation and pathological remodeling of dilated cardiomyopathy (DCM), particularly during the progression of myocardial fibrosis. Additionally, immune cells assume a pivotal role in orchestrating the inflammatory processes, which are intimately linked to the prognosis of DCM. Consequently, understanding the molecular role of various immune cells and their regulation mechanisms would provide an emerging era for managing DCM. In this review, we provide a summary of the most recent advancements in our understanding of the molecular mechanisms of immune cells in DCM. Additionally, we evaluate the effectiveness and limitations of immunotherapy approaches for the treatment of DCM, with the aim of optimizing future immunotherapeutic strategies for this condition.

Thallium exposure induces changes in B and T cell generation in mice

Thallium (Tl) is a high-priority toxic metal that poses a severe threat to human health. The toxicity characteristics induced by Tl have been partially discussed. However, the immunotoxic effects of Tl exposure have remained largely unexplored. Our findings demonstrated that 50 ppm of Tl exposure for one week induced severe weight loss in mice, which was accompanied by appetite suppression. Moreover, although Tl exposure did not induce significant pathological damage to skeletal muscle and bone, Tl inhibited the expression of B cell development-related genes in the bone marrow. Additionally, Tl exposure increased B cell apoptosis and reduced its generation in the bone marrow. Analysis of B cells in the blood indicated that the percentage of B-2 cells decreased significantly, whereas B-2 cell proportions in the spleen did not. The percentage of CD4⁺ T cells in the thymus increased significantly, and the proportion of CD8⁺ T cells did not. Furthermore, although the proportion of the total CD4⁺ and CD8⁺ T cells was not significantly altered in the blood and spleen, Tl exposure promoted the migration of naïve CD4⁺ T cells and recent thymic emigrants (RTEs) from the thymus to the spleen. These results suggest that Tl exposure can affect B and T cell generation and migration, which provides new evidence for Tl-induced immunotoxicity.

Molecular events in the jaw vascular unit: A traditional review of the mechanisms involved in inflammatory jaw bone diseases

Inflammatory jaw bone diseases are common in stomatology, including periodontitis, peri-implantitis, medication-related osteonecrosis of the jaw, radiation osteomyelitis of the jaw, age-related osteoporosis, and other specific infections. These diseases may lead to tooth loss and maxillofacial deformities, severely affecting patients' quality of life. Over the years, the reconstruction of jaw bone deficiency caused by inflammatory diseases has emerged as a medical and socioeconomic challenge. Therefore, exploring the pathogenesis of inflammatory diseases associated with jaw bones is crucial for improving prognosis and developing new targeted therapies. Accumulating evidence indicates that the integrated bone formation and dysfunction arise from complex interactions among a network of multiple cell types, including osteoblast-associated cells, immune cells, blood vessels, and lymphatic vessels. However, the role of these different cells in the inflammatory process and the 'rules' with which they interact are still not fully understood. Although many investigations have focused on specific pathological processes and molecular events in inflammatory jaw diseases, few articles offer a perspective of integration. Here, we review the changes and mechanisms of various cell types in inflammatory jaw diseases, with the hope of providing insights to drive future research in this field.

CD19 (+) B Cell Combined with Prognostic Nutritional Index Predicts the Clinical Outcomes of Patients with Gastric Cancer Who Underwent Surgery

(1) Background: The aim of this study was to explore the predictive ability of lymphocyte subsets for the prognosis of gastric cancer patients who underwent surgery and the prognostic value of CD19 (+) B cell combined with the Prognostic Nutritional Index (PNI). (2) Methods: This study involved 291 patients with gastric cancer who underwent surgery at our institution between January 2016 and December 2017. All patients had complete clinical data and peripheral lymphocyte subsets. Differences in clinical and pathological characteristics were examined using the Chi-square test or independent sample t-tests. The difference in survival was evaluated using Kaplan-Meier survival curves and the Log-rank test. Cox's regression analysis was performed to identify independent prognostic indicators, and nomograms were used to predict survival probabilities. (3) Results: Patients were categorized into three groups based on their CD19 (+) B cell and PNI levels, with 56 cases in group one, 190 cases in group two, and 45 cases in group three. Patients in group one had a shorter progression-free survival (PFS) (HR = 0.444, p < 0.001) and overall survival (OS) (HR = 0.435, p < 0.001). CD19 (+) B cell-PNI had the highest area under the curve (AUC) compared with other indicators, and it was also identified as an independent prognostic factor. Moreover, CD3 (+) T cell, CD3 (+) CD8 (+) T cell, and CD3 (+) CD16 (+) CD56 (+) NK T cell were all negatively correlated with the prognosis, while CD19 (+) B cell was positively associated with the prognosis. The C-index and 95% confidence interval (CI) of nomograms for PFS and OS were 0.772 (0.752-0.833) and 0.773 (0.752-0.835), respectively. (4) Conclusions: Lymphocyte subsets including CD3 (+) T cell, CD3 (+) CD8 (+) T cell, CD3 (+) CD16 (+) CD56 (+) NK T cell, and CD19 (+) B cell were related to the clinical outcomes of patients with gastric cancer who underwent surgery. Additionally, PNI combined with CD19 (+) B cell had higher prognostic value and could be used to identify patients with a high risk of metastasis and recurrence after surgery.

Reduction of peritoneal cavity B1a cells in adult Slc7a5 knockdown mice via dysregulating the mTOR pathway

Slc7a5 is an important amino acid transporter that is highly expressed in metabolically active and rapidly proliferating cells. To explore the effect of Slc7a5 on adult B cell development, we conditionally deleted Slc7a5 in murine B cells and observed a significant reduction of B1a cells. In contrast to PI3K-Akt pathway activation, activity of the mTOR pathway was decreased. This may result from intracellular amino acid starvation in Slc7a5 knockdown (Slc7a5 KD) bone marrow B cells, thereby dampening B1a development. RNA-seq analysis demonstrated increased translation and reduced proliferation in Slc7a5 KD bone marrow B cells. Overall, the results of our study highlight the importance of Slc7a5 in peritoneal B1a cell development.

Targeting immunometabolism against acute lung injury

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are life-threatening conditions triggered by multiple intra- and extra-pulmonary injury factors, characterized by complicated molecular mechanisms and high mortality. Great strides have been made in the field of immunometabolism to clarify the interplay between intracellular metabolism and immune function in the past few years. Emerging evidence unveils the crucial roles of immunometabolism in inflammatory response and ALI. During ALI, both macrophages and lymphocytes undergo robust metabolic reprogramming and discrete epigenetic changes after activated. Apart from providing ATP and biosynthetic precursors, these metabolic cellular reactions and processes in lung also regulate inflammation and immunity.In fact, metabolic reprogramming involving glucose metabolism and fatty acidoxidation (FAO) acts as a double-edged sword in inflammatory response, which not only drives inflammasome activation but also elicits anti-inflammatory response. Additionally, the features and roles of metabolic reprogramming in different immune cells are not exactly the same. Here, we outline the evidence implicating how adverse factors shape immunometabolism in differentiation types of immune cells during ALI and summarize key proteins associated with energy expenditure and metabolic reprogramming. Finally, novel therapeutic targets in metabolic intermediates and enzymes together with current challenges in immunometabolism against ALI were discussed.

Research progress on the active ingredients of traditional Chinese medicine in the intervention of atherosclerosis: A promising natural immunotherapeutic adjuvant

Atherosclerosis (AS) is a chronic inflammatory disease caused by disorders of lipid metabolism. Abnormal deposition of low-density lipoproteins in the arterial wall stimulates the activation of immune cells, including the adhesion and infiltration of monocytes, the proliferation and differentiation of macrophages and lymphocytes, and the activation of their functions. The complex interplay between immune cells coordinates the balance between pro- and anti-inflammation and plays a key role in the progression of AS. Therefore, targeting immune cell activity may lead to the development of more selective drugs with fewer side effects to treat AS without compromising host defense mechanisms. At present, an increasing number of studies have found that the active ingredients of traditional Chinese medicine (TCM) can regulate the function of immune cells in multiple ways to against AS, showing great potential for the treatment of AS and promising clinical applications. In this paper, we review the mechanisms of immune cell action in AS lesions and the potential targets and/or pathways for immune cell regulation by the active ingredients of TCM to promote the understanding of the immune system interactions of AS and provide a relevant basis for the use of active ingredients of TCM as natural adjuvants for AS immunotherapy.

Immune microenvironment: novel perspectives on bone regeneration disorder in osteoradionecrosis of the jaws

Osteoradionecrosis of the jaws (ORNJ) is a severe complication that occurs after radiotherapy of head and neck malignancies. Clinically, conservative treatments and surgeries for ORNJ exhibited certain therapeutic effects, whereas the regenerative disorder of the post-radiation jaw remains a pending problem to be solved. In recent years, the recognition of the role of the immune microenvironment has led to a shift from an osteoblasts (OBs) or bone marrow mesenchymal stromal cells (BMSCs)-centered view of bone regeneration to the concept of a complicated microecosystem that supports bone regeneration. Current advances in osteoimmunology have uncovered novel targets within the immune microenvironment to help improve various regeneration therapies, notably therapies potentiating the interaction between BMSCs and immune cells. However, these researches lack a thorough understanding of the immune microenvironment and the interaction network of immune cells in the course of bone regeneration, especially for the post-operative defect of ORNJ. This review summarized the composition of the immune microenvironment during bone regeneration, how the immune microenvironment interacts with the skeletal system, and discussed existing and potential strategies aimed at targeting cellular and molecular immune microenvironment components.

The mechanism and therapy of aortic aneurysms

Aortic aneurysm is a chronic aortic disease affected by many factors. Although it is generally asymptomatic, it poses a significant threat to human life due to a high risk of rupture. Because of its strong concealment, it is difficult to diagnose the disease in the early stage. At present, there are no effective drugs for the treatment of aneurysms. Surgical intervention and endovascular treatment are the only therapies. Although current studies have discovered that inflammatory responses as well as the production and activation of various proteases promote aortic aneurysm, the specific mechanisms remain unclear. Researchers are further exploring the pathogenesis of aneurysms to find new targets for diagnosis and treatment. To better understand aortic aneurysm, this review elaborates on the discovery history of aortic aneurysm, main classification and clinical manifestations, related molecular mechanisms, clinical cohort studies and animal models, with the ultimate goal of providing insights into the treatment of this devastating disease. The underlying problem with aneurysm disease is weakening of the aortic wall, leading to progressive dilation. If not treated in time, the aortic aneurysm eventually ruptures. An aortic aneurysm is a local enlargement of an artery caused by a weakening of the aortic wall. The disease is usually asymptomatic but leads to high mortality due to the risk of artery rupture.

Bone marrow mesenchymal stem cells repress renal transplant immune rejection by facilitating the APRIL phosphorylation to induce regulation B cell production

Bone marrow mesenchymal stem cells (BMSCs) exert pivotal roles in suppressing immune rejection in organ transplantation. However, the function of BMSCs on immune rejection in renal transplantation remains unclear. This study aimed to evaluate the effect and underlying mechanism of BMSCs on immune rejection in renal transplantation. Following the establishment of the renal allograft mouse model, the isolated primary BMSCs were injected intravenously into the recipient mice. Enzyme-linked immunosorbent assay, flow cytometry, hematoxylin-eosin staining, and Western blot assays were conducted to investigate BMSCs' function in vivo and in vitro. Mechanistically, the underlying mechanism of BMSCs on immune rejection in renal transplantation was investigated in in vivo and in vitro models. Functionally, BMSCs alleviated the immune rejection in renal transplantation mice and facilitated B cell activation and the production of IL-10⁺ regulatory B cells (Bregs). Furthermore, the results of mechanism studies revealed that BMSCs induced the production of IL-10⁺ Bregs by facilitating a proliferation-inducing ligand (APRIL) phosphorylation to enhance immunosuppression and repressed renal transplant rejection by promoting APRIL phosphorylation to induce IL-10⁺ Bregs. BMSCs prevent renal transplant rejection by facilitating APRIL phosphorylation to induce IL-10⁺ Bregs.

Current understanding of the immune potential of B-cell subsets in malarial pathogenesis

In the past several decades, our understanding of how B cells are generated and what function they perform has continued to advance. It is widely accepted that B-cell subsets play a critical role in mediating immune response. Surprisingly, human and murine malarial infections cause major alterations in the composition of B-cell subsets in both the spleen and periphery. Multiple B-cell subsets are well characterized in murine models following primary and secondary infection, although in human malarial infection, these subsets are not well defined. Furthermore, a rare known function of B cells includes the potential role of regulating the activities of other cells in the body as regulatory cells. Plasmodium infection strongly alters the frequency of these regulatory B cells indicating the immunoregulatory function of B cells in malarial. It is important to note that these subsets, taken together, form the cellular basis of humoral immune responses, allowing protection against a wide array of Plasmodium antigens to be achieved. However, it remains a challenge and an important area of investigation to understand how these B-cell subsets work together to provide protection against Plasmodium infection.

Role of macrophages in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a severe cardiopulmonary vascular disease characterized by progressive pulmonary artery pressure elevation, increased pulmonary vascular resistance and ultimately right heart failure. Studies have demonstrated the involvement of multiple immune cells in the development of PAH in patients with PAH and in experimental PAH. Among them, macrophages, as the predominant inflammatory cells infiltrating around PAH lesions, play a crucial role in exacerbating pulmonary vascular remodeling in PAH. Macrophages are generally polarized into (classic) M1 and (alternative) M2 phenotypes, they accelerate the process of PAH by secreting various chemokines and growth factors (CX3CR1, PDGF). In this review we summarize the mechanisms of immune cell action in PAH, as well as the key factors that regulate the polarization of macrophages in different directions and their functional changes after polarization. We also summarize the effects of different microenvironments on macrophages in PAH. The insight into the interactions between macrophages and other cells, chemokines and growth factors may provide important clues for the development of new, safe and effective immune-targeted therapies for PAH.

Molecular Bases of Protein Antigenicity and Determinants of Immunogenicity, Anergy, and Mitogenicity

BACKGROUND

The immune system is able to recognize substances that originate from inside or outside the body and are potentially harmful. Foreign substances that bind to immune system components exhibit antigenicity and are defined as antigens. The antigens exhibiting immunogenicity can induce innate or adaptive immune responses and give rise to humoral or cell-mediated immunity. The antigens exhibiting mitogenicity can cross-link cell membrane receptors on B and T lymphocytes leading to cell proliferation. All antigens vary greatly in physicochemical features such as biochemical nature, structural complexity, molecular size, foreignness, solubility, and so on.

OBJECTIVE

Thus, this review aims to describe the molecular bases of protein-antigenicity and those molecular bases that lead to an immune response, lymphocyte proliferation, or unresponsiveness.

CONCLUSION

The epitopes of an antigen are located in surface areas; they are about 880-3,300 Da in size. They are protein, carbohydrate, or lipid in nature. Soluble antigens are smaller than 1 nm and are endocytosed less efficiently than particulate antigens. The more the structural complexity of an antigen increases, the more the antigenicity increases due to the number and variety of epitopes. The smallest immunogens are about 4,000-10,000 Da in size. The more phylogenetically distant immunogens are from the immunogen-recipient, the more immunogenicity increases. Antigens that are immunogens can trigger an innate or adaptive immune response. The innate response is induced by antigens that are pathogen-associated molecular patterns. Exogenous antigens, T Dependent or T Independent, induce humoral immunogenicity. TD protein-antigens require two epitopes, one sequential and one conformational to induce antibodies, whereas, TI non-protein-antigens require only one conformational epitope to induce low-affinity antibodies. Endogenous protein antigens require only one sequential epitope to induce cell-mediated immunogenicity.

Cultivation of Encapsulated Primary Human B Lymphocytes: A First Step toward a Bioartificial Germinal Center

Polyelectrolyte microcapsules based on sodium cellulose sulfate (SCS) and poly-diallyl-dimethyl-ammonium chloride (PDADMAC) have previously been proposed as a suitable ex vivo microenvironment for the cultivation and differentiation of primary human T lymphocytes. Here, the same system is investigated for the cultivation of human primary B cells derived from adult tonsillar tissue. Proliferation and differentiation into subtypes are followed and compared to suspension cultures of B cells from the same pool performed in parallel. Total cell expansion is somewhat lower in the capsules than in the suspension cultures. More importantly, however, the differentiation of the initially mainly memory B cells into various subtypes, in particular into plasma cell (PC), shows significant differences. Clearly, the microenvironment provided by the microcapsules is beneficial for an accelerated induction of a germinal center-like B cell phenotype and afterward supports the long-term survival of the PC cells. Then, varying the encapsulation conditions (i.e., presence of human serum and dedicated cytokines in the capsule core) provides a tool for finetuning the B cell response. Hence, this methodology is suggested to pave the way toward ex vivo development of human immune organoids.

Assessment of adaptive immune responses of dairy cows with Burkholderia contaminans-induced mastitis

Burkholderia contaminans, an emerging pathogen related to cystic fibrosis, is known to cause potentially fatal infections in humans and ruminants, especially in immunocompromised individuals. However, the immune responses in cows following its infection have not been fully elucidated. In this study, T- and B-lymphocytes-mediated immune responses were evaluated in 15 B. contaminans-induced mastitis cows and 15 healthy cows with multi-parameter flow cytometry. The results showed that infection with B. contaminans was associated with a significant decrease in the number and percentage of B lymphocytes but with a significant increase in the proportion of IgG⁺CD27⁺ B lymphocytes. This indicated that humoral immune response may not be adequate to fight intracellular infection, which could contribute to the persistent bacterial infection. In addition, B. contaminans infection induced significant increase of γδ T cells and double positive (DP) CD4⁺CD8⁺ T cells but not CD4⁺ or CD8⁺ (single positive) T cells in blood. Phenotypic analysis showed that the percentages of activated WC1⁺ γδ T cells in peripheral blood were increased in the B. contaminans infected cows. Interestingly, intracellular cytokine staining showed that cattle naturally infected with B. contaminans exhibited multifunctional TNF-α⁺IFN-γ⁺IL-2⁺ B. contaminans-specific DP T cells. Our results, for the first time, revealed a potential role of IgG⁺CD27⁺ B cells, CD4⁺CD8⁺ T cells and WC1⁺ γδ T cells in the defense of B. contaminans-induced mastitis in cows.

Unraveling the role of Breg cells in digestive tract cancer and infectious immunity

Over the past two decades, regulatory B cells (Breg cells or Bregs) have emerged as an immunosuppressive subset of B lymphocytes playing a key role in inflammation, infection, allergy, transplantation, and cancer. However, the involvement of Bregs in various pathological conditions of the gastrointestinal tract is not fully understood and is the subject of much recent research. In this review, we aimed to summarize the current state of knowledge about the origin, phenotype, and suppressive mechanisms of Bregs. The relationship between the host gut microbiota and the function of Bregs in the context of the disturbance of mucosal immune homeostasis is also discussed. Moreover, we focused our attention on the role of Bregs in certain diseases and pathological conditions related to the digestive tract, especially Helicobacter pylori infection, parasitic diseases (leishmaniasis and schistosomiasis), and gastrointestinal neoplasms. Increasing evidence points to a relationship between the presence and number of Bregs and the severity and progression of these pathologies. As the number of cases is increasing year by year, also among young people, it is extremely important to understand the role of these cells in the digestive tract.

Immune related biomarkers for cancer metastasis to the brain

Brain metastasis accounts for a large number of cancer-related deaths. The host immune system, involved at each step of the metastatic cascade, plays an important role in both the initiation of the brain metastasis and their treatment responses to various modalities, through either local and or systemic effect. However, few reliable immune biomarkers have been identified in predicting the development and the treatment outcome in patients with cancer brain metastasis. Here, we provide a focused perspective of immune related biomarkers for cancer metastasis to the brain and a thorough discussion of the potential utilization of specific biomarkers such as tumor mutation burden (TMB), genetic markers, circulating and tumor-infiltrating immune cells, cytokines, in predicting the brain disease progression and regression after therapeutic intervention. We hope to inspire the field to extend the research and establish practical guidelines for developing and validating immune related biomarkers to provide personalized treatment and improve treatment outcomes in patients with metastatic brain cancers.

H3K36 methyltransferase NSD1 is essential for normal B1 and B2 cell development and germinal center formation

B cells, which consist of two well-defined populations: B1 and B2 cells, which can produce antibodies that are essential for host protection against infections, through virus neutralization, opsonization and antibody-dependent cellular cytotoxicity. Epigenetic modifications, such as DNA methylation and histone modification could regulate immune cell differentiation and functions. In this study, we found a significant reduction of GC response in the B cell specific knockout of H3K36 methyltransferase NSD1 (Mb1-Cre⁺ NSD1^fl/fl, NSD1^{B KO}) mice compared with the wildtype control (Mb1-Cre⁺ NSD1^+/+, NSD1^{B WT}). We also demonstrated reduced production of high-affinity antibody, but increased production of low-affinity antibody in the NSD1^{B KO} mice. Further analysis revealed that loss of NSD1 promoted the development of B1 cells by increasing the expression of Rap1b and Arid3a. In conclusion, our data suggest that NSD1 plays an important role in regulation the development of B1 and B2 cells, and the process of germinal center formation and high-affinity antibody production.

Correlation between Clinical and Immunological Variables and Humoral Response to SARS-CoV-2 Vaccination in Adult Patients with Antibody Deficiency Disorders

BACKGROUND

Prophylactic vaccination has proven to be the most effective strategy to fight the COVID-19 pandemic.

METHODS

This was a prospective observational cohort study involving 30 predominantly antibody deficiency disorders (ADD)-afflicted adult patients on immunoglobulin replacement therapy vaccinated with three doses of the mRNA-1273 COVID-19 vaccine, and 10 healthy controls. Anti-RBD IgG antibodies were determined in plasma samples collected just before the first dose of mRNA-based COVID-19 vaccine and on weeks 4, 8, 24, and 28 following the first vaccination. Patients were categorized based on the levels of anti-RBD antibodies determined on w8 as non-, low-, and responders. Chi-square and Kruskal-Wallis tests were used to see if any variables correlated with humoral response levels. Any adverse effects of the mRNA-based vaccine were also noted.

RESULTS

The COVID-19 vaccine was safe and well-tolerated. The humoral response elicited at w8 after vaccination depended on the type of ADD, the type of immunoglobulin deficiency, the presence of granulomatous lymphocytic interstitial lung disease, recent use of immunosuppressive drugs, and the switched memory B cells counts. The third vaccine dose boosted humoral response in previous responders to second dose but seldom in non-responders.

CONCLUSIONS

The humoral response of patients with predominant ADD depends mostly on the type of immunodeficiency and on the frequency of B and T cell populations.

The emerging roles and therapeutic potential of B cells in sepsis

Sepsis is a life-threatening syndrome caused by anomalous host response to infection. The pathogenesis of sepsis is complex, and immune dysfunction is the central link in its occurrence and development. The sepsis immune response is not a local and transient process but a complex and continuous process involving all major cell types of innate and adaptive immunity. B cells are traditionally studied for their ability to produce antibodies in the context of mediating humoral immunity. However, over the past few years, B cells have been increasingly recognized as key modulators of adaptive and innate immunity, and they can participate in immune responses by presenting antigens, producing cytokines, and modulating other immune cells. Recently, increasing evidence links B-cell dysfunction to mechanisms of immune derangement in sepsis, which has drawn attention to the powerful properties of this unique immune cell type in sepsis. Here, we reviewed the dynamic alterations of B cells and their novel roles in animal models and patients with sepsis, and provided new perspectives for therapeutic strategies targeting B cells in sepsis.