B-cell biology and development

The role of fatty acid metabolism on B cells and B cell-related autoimmune diseases

Fatty acid metabolism plays a critical role in regulating immune cell function, including B cells, which are central to humoral immunity and the pathogenesis of autoimmune diseases. Emerging evidence suggests that fatty acid metabolism influences B cell development, activation, differentiation, and antibody production, thereby impacting B cell-related autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and multiple sclerosis (MS). In this review, we discuss the mechanisms by which fatty acid metabolism modulates B cell biology, including energy provision, membrane composition, and signaling pathways. We highlight how alterations in fatty acid synthesis, oxidation, and uptake affect B cell function and contribute to autoimmune pathogenesis. Additionally, we explore the therapeutic potential of targeting fatty acid metabolism in B cells to treat autoimmune diseases. Understanding the interplay between fatty acid metabolism and B cell immunity may provide novel insights into the development of precision therapies for B cell-mediated autoimmune disorders.

Simultaneous polyclonal antibody sequencing and epitope mapping by cryo electron microscopy and mass spectrometry

Antibodies are a major component of adaptive immunity against invading pathogens. Here, we explore possibilities for an analytical approach to characterize the antigen-specific antibody repertoire directly from the secreted proteins in convalescent serum. This approach aims to perform simultaneous antibody sequencing and epitope mapping using a combination of single particle cryo-electron microscopy (cryoEM) and bottom-up proteomics techniques based on mass spectrometry (LC-MS/MS). We evaluate the performance of the deep-learning tool ModelAngelo in determining de novo antibody sequences directly from reconstructed 3D volumes of antibody-antigen complexes. We demonstrate that while map quality is a critical bottleneck, it is possible to sequence antibody variable domains from cryoEM reconstructions with accuracies of up to 80-90%. While the rate of errors exceeds the typical levels of somatic hypermutation, we show that the ModelAngelo-derived sequences can be used to assign the used V-genes. This provides a functional guide to assemble de novo peptides from LC-MS/MS data more accurately and improves the tolerance to a background of polyclonal antibody sequences. Following this proof-of-principle, we discuss the feasibility and future directions of this approach to characterize antigen-specific antibody repertoires.

Phosphatidylcholine and frailty: a Mendelian randomization study and immune mediation

OBJECTIVE

Lipid metabolism plays a significant role in the aging process, and the prevalence of frailty increases with advancing age. However, few studies have employed Mendelian randomization (MR) to investigate the associations between lipids and frailty.

METHODS

This study utilized large-scale genome-wide association study (GWAS) and a bidirectional two-sample, two-step MR approach to explore the causal associations of 179 lipid species with the frailty index (FI) and the mediating effects of immune cells. The inverse variance weighted (IVW) method was used primarily to evaluate the MR results. Heterogeneity and horizontal pleiotropy were assessed via Cochran's Q, the MR-Egger intercept, MR-PRESSO and leave-one-out analysis. Phenome-wide MR (Phe-MR) was used to analyse the potential roles of frailty-related phosphatidylcholine species in diseases.

RESULTS

MR analysis revealed a causal relationship between PC species and FI. Specifically, PC (18:0_20:5), LPC (18:0_0:0), LPC (16:0_0:0), and ether-PC (O-16:0_22:5) are positively correlated with the FI, whereas PC(18:1_20:2), PC(16:0_18:3), PC(16:0_20:1), ether-PC (O-18:0_16:1), and ether-PC (O-16:1_16:0) are negatively correlated with the FI. Reverse MR analysis indicated no strong association between the FI and the nine PCs. Mediation analysis revealed that Sw mem %lymphocyte partially mediated the effect of LPC (18:0_0:0) on FI. Phe-MR analysis revealed that nine frailty-related PCs were broadly associated with various diseases.

CONCLUSION

This study provides novel evidence that supports the causal association between PC species and frailty, with the immune system playing a crucial role in this pathway. These findings offer new insights into potential targets for the intervention of frailty in the elderly population.

Crucial Roles of RSAD2/viperin in Immunomodulation, Mitochondrial Metabolism and Autoimmune Diseases

Autoimmune diseases are typically characterized by aberrant activation of immune system that leads to excessive inflammatory reactions and tissue damage. Nevertheless, precise targeted and efficient therapies are limited. Thus, studies into novel therapeutic targets for the management of autoimmune diseases are urgently needed. Radical S-adenosyl methionine domain-containing 2 (RSAD2) is an interferon-stimulated gene (ISG) renowned for the antiviral properties of the protein it encodes, named viperin. An increasing number of studies have underscored the new roles of RSAD2/viperin in immunomodulation and mitochondrial metabolism. Previous studies have shown that there is a complex interplay between RSAD2/vipeirn and mitochondria and that binding of the iron-sulfur (Fe-S) cluster is necessary for the involvement of viperin in mitochondrial metabolism. Viperin influences the proliferation and development of immune cells as well as inflammation via different signaling pathways. However, the function of RSAD2/viperin varies in different studies and a comprehensive overview of this emerging theme is lacking. This review will describe the characteristics of RSAD2/viperin, decipher its function in immunometabolic processes, and clarify the crosstalk between RSAD2/viperin and mitochondria. Furthermore, we emphasize the crucial roles of RSAD2 in autoimmune diseases and its potential application value.

Identification of new immune target and signaling for cancer immunotherapy

Immunotherapy has become one of the innovative treatments in malignancy as it activates the immune system to find and eliminate malignant cells. The tumor immunology interface has become increasingly intricate, making the identification of new immune targets and signalling pathways on which to base improved therapeutic strategies an ongoing process. This review, we goal to clarify the contacts between cancer and immune system with a focus on immune surveillance as well as immune evasion mechanisms. Comprehensive immunotherapeutic therapies are overviewed with ICI (CTLA-4, PD-1, PD-L1), CAR-T cell therapy, and cancer vaccines whereas, advanced therapies targeting new immune checkpoints are also elucidated including TIM-3, LAG-3, and TIGIT. The JAK/STAT, MAPK and PI3K-AKT-mTOR pathways are reviewed with regards to cancer progression and immunotherapeutic resistance. The dysregulation of these pathways gives hope for the identification of fresh targets for therapy. Genomics, proteomics, immunopeptidomics, single cell mass spectrometry, CRISPR-based functional genomics and bioinformatics are described as essential for immune target identification and for mapping of cancer relevant signaling pathways. This review also considers some emerging issues in the subject area like the tumor heterogeneity, immune-related adverse events (irAEs), and personalized treatment. These barriers are described to facilitate the understanding of ways to overcome them and increase the efficacy of immunotherapies through combination therapies. This means that by developing new knowledge of immunological targets and pathways, immunoprecision medicine for cancer could greatly enhance outcomes.

Usp11 maintained the survival of marginal zone B cells under ionizing radiation by deubiquitinating DLL1 and JAG2

Efficacy of radiation therapy is compromised by hematopoietic and immune impairments, with elusive underlying causes. This study aimed to elucidate Usp11's role in radiation-induced injuries and uncover related mechanisms. Utilized ARS mouse model to observe survival rates of Usp11-/- (KO) mice post-TBI (Total Body Irradiation). Assessed lymphocyte and MZ B (Marginal Zone B) cell rates using histological analysis, single-cell sequencing, immunofluorescence (IF), immunohistochemistry (IHC), and flow cytometry (FCM). Conducted Co-IP and ubiquitination experiments for mechanism elucidation. Quantified IgM and IgG using ELISA and FC. Explored public databases for potential correlation molecules. Our findings indicated that Usp11-/- mice exhibited improved survival rates following TBI, with the spleen playing a pivotal role. HE staining revealed a wider marginal zone in the spleen of Usp11+/+ mice post-irradiation. Single-cell sequencing, IF, IHC, and FCM analyses revealed a higher survival rate of MZ B cells in Usp11-/- mice after irradiation. Furthermore, treatment with the Usp11 inhibitor, mitoxantrone, successfully targeted and inhibited Usp11, thereby alleviating the reduction in MZ B cells in the spleen following total body irradiation. Mechanistically, Usp11 sustained the survival of MZ B cells by regulating the ubiquitination of Notch's ligands, DLL1 and JAG2, thereby promoting immune cell remodeling in the spleen. In conclusion, Usp11 played a crucial role in modulating immune system damage induced by ionizing radiation, primarily through ubiquitination of Notch ligands. This study provides insights into radiation-induced immune injuries and suggests Usp11 as a potential therapeutic target.

Active immunization against gonadotropin-releasing hormone enhances the generation of B cells but does not affect their colonization in peripheral immune organs in male rats

Active immunization against gonadotropin-releasing hormone (GnRH) affects the immune system by inhibiting testosterone production. Our previous study investigated the effects of GnRH immunization on thymic T-cell generation, migration, and colonization in peripheral immune organs. However, the mechanisms by which GnRH immunization influences B cell generation and the characteristics of B cell colonization in peripheral immune organs remain unclear. Herein, GnRH immunization enhanced B cell generation by reducing apoptosis. GnRH immunization did not markedly affect the cell cycle of bone marrow cells, B cell development-related signaling molecules, or the percentage of B cells in the blood, spleen, or inguinal lymph nodes. After testosterone supplementation in GnRH-immunocastrated rats, the generation of B cells in the bone marrow was significantly reduced, and the apoptosis of B cells was remarkably increased. Testosterone did not significantly affect the cell cycle of bone marrow cells or the proportion of B cells in the blood, spleen, or inguinal lymph nodes of the GnRH-immunocastrated rats. Overall, these results clarify the mechanisms related to B cell expansion in the bone marrow and the settlement characteristics of B cells in peripheral immune organs after GnRH immunization.

Multi-dimensional analysis of B cells reveals the expansion of memory and regulatory B-cell clusters in humans living in rural tropical areas

B-cells play a critical role in the formation of immune responses against pathogens by acting as antigen-presenting cells, by modulating immune responses, and by generating immune memory and antibody responses. Here, we studied B-cell subset distributions between regions with higher and lower microbial exposure, i.e. by comparing peripheral blood B-cells from people living in Indonesia or Ghana to those from healthy Dutch residents using a 36-marker mass cytometry panel. By applying an unbiased multidimensional approach, we observed differences in the balance between the naïve and memory compartments, with higher CD11c+ and double negative (DN-IgDnegCD27neg) memory (M)B-cells in individuals from rural tropical areas, and conversely lower naïve B-cells compared to residents from an area with less pathogen exposure. Furthermore, characterization of total B-cell populations, CD11c+, DN, and Breg cells showed the emergence of specific memory clusters in individuals living in rural tropical areas. Some of these differences were more pronounced in children compared to adults and suggest that a higher microbial exposure accelerates memory B-cell formation, which "normalizes" with age.

The B-cells paradigm in systemic sclerosis: an update on pathophysiology and B-cell-targeted therapies

Systemic sclerosis (SSc) is considered a rare autoimmune disease in which there are alterations of both the innate and adaptive immune response resulting in the production of autoantibodies. Abnormalities of the immune system compromise the normal function of blood vessels leading to a vasculopathy manifested by Raynaud's phenomenon, an early sign of SSc . As a consequence of this reactive picture, the disease can evolve leading to tissue fibrosis. Several SSc-specific autoantibodies are currently known and are associated with specific clinical manifestations and prognosis. Although the pathogenetic role of these autoantibodies is still unclear, their production by B cells and plasma cells suggests the importance of these cells in the development of SSc. This review narratively examines B-cell dysfunctions and their role in the pathogenesis of SSc and discusses B-cell-targeted therapies currently used or potentially useful for the management of end-organ complications.

CCN1 promotes APRIL/BAFF signaling in esophageal squamous cell carcinoma but attenuates it in esophageal adenocarcinoma

CCN1 is a matricellular protein highly expressed in esophageal squamous cell carcinoma (ESCC) but hardly detectable in esophageal adenocarcinoma (EAC). Expression of CCN1 in EAC cells leads to TRAIL-mediated apoptosis. Unlike TRAIL, which primarily triggers cell death, APRIL and BAFF promote cell growth via NFκB signaling. They become active ligands by Furin cleavage. This study found that CCN1 upregulated APRIL and BAFF expression in both ESCC and EAC cells but attenuated their signaling in the latter. CCN1 kept Furin stable in ESCC allowing APRIL/BAFF to signal through their common receptor BCMA properly. In EAC cells, however, expression of CCN1 lowered Furin activity and thus limited APRIL/BAFF cleavage. As a result, ESCC cells benefited from CCN1 while EAC cell viability was attenuated by it.

Integrative analysis of Ewing's sarcoma reveals that the MIF-CD74 axis is a target for immunotherapy

BACKGROUND

Ewing's sarcoma (EwS), a common pediatric bone cancer, is associated with poor survival due to a lack of therapeutic targets for immunotherapy or targeted therapy. Therefore, more effective treatment options are urgently needed.

METHODS

Since novel immunotherapies may address this need, we performed an integrative analysis involving single-cell RNA sequencing, cell function experiments, and humanized models to dissect the immunoregulatory interactions in EwS and identify strategies for optimizing immunotherapeutic efficacy.

RESULTS

EwS is infiltrated by immunosuppressive myeloid populations, T and B lymphocytes, and natural killer cells. We found that SLC40A1 and C1QA macrophages were associated with a poor prognosis, whereas CD8+ T-cell infiltration was associated with a good prognosis. A comparative analysis of paired samples revealed that in tumors with a good chemotherapeutic response, macrophages presented increased antigen presentation and reduced release of protumor cytokines, whereas CD8+ T cells presented increased cytotoxicity and reduced exhaustion. An interaction analysis revealed a vast immunoregulatory network and identified MIF-CD74 as a crucial immunoregulatory target that can simultaneously promote M2 polarization of macrophages and inhibit CD8+ T-cell infiltration. Importantly, MIF blockade effectively reshaped the tumor immune microenvironment, turning cold tumors hot and inhibiting tumor growth.

CONCLUSIONS

Our integrative analysis revealed that the MIF/CD74 axis is a promising target for the treatment of Ewing sarcoma and provides a rationale for this novel immunotherapy.

Immune Tolerance Regulation Is Critical to Immune Homeostasis

The body's immune response plays a critical role in defending against external or foreign antigens while also preserving tolerance to self-antigens. This equilibrium, referred to as immune homeostasis, is paramount for overall health. The regulatory mechanisms governing the maintenance of this delicate immune balance are notably complex. It is currently accepted that immune tolerance is a dynamic outcome regulated by multiple factors, including central and peripheral mechanisms. Its induction or elimination plays a significant role in autoimmune diseases, organ transplantation, and cancer therapy, markedly impacting various major diseases in modern clinical practice. Overall, our current understanding of immune tolerance is still very limited. In this review article, we summarized the main mechanisms that have been known to mediate immune tolerance so far, including endogenous immune tolerance, adaptive immune tolerance, other immune tolerance mechanisms, and the homeostasis of immune tolerance, identified the key factors that regulate immune tolerance, and provided new clues for immune system recovery in many autoimmune diseases, organ transplantation, and tumor therapy.

Antibiotic use attenuates response to immune checkpoint blockade in urothelial carcinoma via inhibiting CD74-MIF/COPA: revealing cross-talk between anti-bacterial immunity and ant-itumor immunity

BACKGROUND

Immune checkpoint blockade (ICB) has emerged as a promising therapy for both resectable urothelial carcinoma (UC) patients preparing for radical surgery and unresectable UC patients, whereas the objective response rate of ICB remains unsatisfactory due to various factors. Antibiotic (ATB) use can influence intratumoral bacteria, which may further reduce ICB efficacy. The study aims to evaluate the effects of ATB use on prognosis and response in UC patients undergoing ICB, and explore potential molecular mechanisms of ATBs and intratumoral bacteria impacting UC immune microenvironment.

MATERIALS AND METHODS

Pooled analyses, synthesizing evidence from 3496 UC patients with ICB treatment, were conducted. In addition, single-cell RNA and single-cell microbiome data were analyzed based on eight UC samples and 63 185 single cells. Bulk RNA sequencing and clinical data from a single-arm, multicenter, atezolizumab-treated, phase 2 trial, IMvigor210, were used for validation.

RESULTS

ATB use exhibited worse overall survival (HR=1.46, 95% CI=[1.20-1.77], P <0.001 and lower objective response (OR=0.43, 95% CI=[0.27-0.68], P <0.001 in UC patients receiving ICB. Single-cell transcriptome and single-cell microbiome analyses identified the presence of intratumoral bacteria was obviously related to elevated antibacterial immune functions; and antibacterial immunity was positively correlated to antitumor immunity in UC immune microenvironment. Intratumoral bacteria could up-regulate CD74-MIF/COPA signaling of immune cells and activation of CD74-MIF/COPA mediated the promotion of T cell antitumor function induced by antibacterial immune cells. UC patients with higher CD74-MIF/COPA signaling carried better overall survival (HR=1.60, 95% CI=[1.19-2.15], P =0.002) in immunotherapy cohort.

CONCLUSION

ATB use reduces overall survival and objective response to ICB in UC patients. Antibacterial immune cell functions induced by intracellular bacteria in the UC microenvironment might up-regulate the function of antitumor T immune cells via activating CD74-MIF/COPA , whereas ATB could inhibit the above process through killing intracellular bacteria and result in poorer clinical benefit of ICB. The use of ATB should be considered carefully during the neoadjuvant immunotherapy period for resectable UC patients preparing for radical surgery and during the immunotherapy period for unresectable UC patients.

Immunoregulatory programs in anti-N-methyl-D-aspartate receptor encephalitis identified by single-cell multi-omics analysis

BACKGROUND

Anti-N-methyl-D-aspartate receptor encephalitis (anti-NMDARE) is a prevalent type of autoimmune encephalitis caused by antibodies targeting the NMDAR's GluN1 subunit. While significant progress has been made in elucidating the pathophysiology of autoimmune diseases, the immunological mechanisms underlying anti-NMDARE remain elusive. This study aimed to characterize immune cell interactions and dysregulation in anti-NMDARE by leveraging single-cell multi-omics sequencing technologies.

METHODS

Peripheral blood mononuclear cells (PBMCs) from patients in the acute phase of anti-NMDARE and healthy controls were sequenced using single-cell joint profiling of transcriptome and chromatin accessibility. Differential gene expression analysis, transcription factor activity profiling, and cell-cell communication modeling were performed to elucidate the immune mechanisms underlying the disease. In parallel, single-cell B cell receptor sequencing (scBCR-seq) and repertoire analysis were conducted to assess antigen-driven clonal expansion within the B cell population.

RESULTS

The study revealed a significant clonal expansion of B cells, particularly plasma cells, in anti-NMDARE patients. The novel finding of type I interferon (IFN-I) pathway activation suggests a regulatory mechanism that may drive this expansion and enhance antibody secretion. Additionally, activation of Toll-like receptor 2 (TLR2) in myeloid cells was noted, which may connect to tumor necrosis factor-alpha (TNF-α) secretion. This cytokine may contribute to the activation of B and T cells, thereby perpetuating immune dysregulation.

CONCLUSIONS

This study presents a comprehensive single-cell multi-omics characterization of immune dysregulation in anti-NMDARE, highlighting the expansion of B cell and the activation of the IFN-I and TLR2 pathways. These findings provide deeper insights into the molecular mechanism driving the pathogenesis of anti-NMDARE and offer promising targets for future therapeutic intervention.

KEY POINTS

Significant B cell clonal expansion, particularly in plasma cells, driven by antigen recognition. IFN-I pathway activation in plasma cells boosts their antibody production and potentially exacerbates immune dysregulation. TLR2 pathway activation in myeloid cells contributes to TNF-α secretion and could influence adaptive immune responses.

The Pathogenesis of Nephrotic Syndrome: A Perspective from B Cells

Background

Nephrotic syndrome is a special type of chronic kidney disease, the specific pathogenesis of which remains unclear. An increasing number of studies have suggested that B cells play an important role in the pathogenesis of nephrotic syndrome.

Summary

Idiopathic nephrotic syndrome is a common kidney disease in children. While previously believed to be primarily caused by T-cell disorders, recent research has shifted its focus to B cells. Studies have shown that B cells play a significant role in the pathogenesis of NS, potentially even more so than T cells. This article provides a comprehensive review of the involvement of B cells in the development of idiopathic nephrotic syndrome.

Key Messages

B cells are involved in the pathogenesis of nephrotic syndrome by producing autoantibodies and various cytokines.

Advances in the treatment of mantle cell lymphoma with BTK inhibitors

Mantle cell lymphoma (MCL) is a heterogenous disease that is one of the most challenging blood cancers due to its poor prognosis, high risk of relapse and drug resistance. Recent researches have brought significant changes in MCL patients outcomes and new clinical. Bruton's Tyrosine Kinase (BTK), a key kinase in the B-cell antigen receptor (BCR) signaling pathway, is a clinical research hot spot and plays a major role in the survival and spread of malignant B cells. The first generation of BTK inhibitors, led by ibrutinib, have shown promising results in targeted treatment. Meanwhile, several inhibitors have entered clinical studies and demonstrated outstanding therapeutic activity in clinical trials for MCL, indicating a good prospect for development. Despite these encouraging findings, the duration of response is limited, and resistance to BTK inhibitors develops in a portion of individuals. This review summarizes the pathogenesis of MCL and targeted BTK inhibitors and provides an overview of the mutations that can lead to resistance to BTK inhibitors. The purpose of this article is to review the literature describing these selective therapies and provides perspectives for their further development.

Identification of necroptosis-related gene expression and the immune response in polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common reproductive and endocrine disorder; however, the understanding of the pathogenesis of PCOS remains unclear. Necroptosis is a newly discovered mechanism of cell death, and it is closely related to reproductive endocrine-related diseases. This study aimed to investigate the hub necroptosis-related genes in PCOS patients and its correlation with immune cell infiltration by bioinformatics methods.

METHOD

The gene expression chip result matrix and the annotation matrix files of the GSE34526, GSE8157, and GSE5090 datasets were downloaded from the GEO database. We analyzed the expression and correlation of the necroptosis-related genes in all samples, constructed a diagnostic model based on all necroptosis-related genes and genes with significant differences, performed unsupervised clustering of samples and gene enrichment analysis, and evaluated the correlations between the hub gene and immune cell infiltration levels by the R packages GSVA and CIBERSORT. Finally, PPI networks were constructed using the Cytoscape software GeneMANIA plug-in, and the miRNA, transcription factors, RBP, and drugs were predicted.

CONCLUSION

Necroptosis-related genes have important relationships in the development of PCOS and are potentially associated with immune infiltration in PCOS patients.

The causal relationship between type 2 diabetes mellitus and isolated REM sleep behavior disorder: results from multivariable and network Mendelian randomization analysis

Objectives

To investigate the causal relationship between type 2 diabetes mellitus (T2DM, exposure) and isolated REM sleep behavior disorder (iRBD, outcome).

Methods

Genome-wide association study (GWAS) data for iRBD comprised 9,447 samples, including 1,061 iRBD cases from the International RBD Study Group. Initially, we performed linkage disequilibrium score regression (LDSC) to explore the genetic correlation between T2DM and iRBD. Then the two-sample univariate MR (UVMR) analysis was conducted to examine the effects of T2DM and blood sugar metabolism-related factors on iRBD. Subsequently, we applied multivariable MR (MVMR) methods to further adjust for confounders. Lastly, we executed a network MR analysis, with cytokines and immune cell characteristics as potential mediators, aiming to investigate indirect effect of T2DM on iRBD.

Results

Results from LDSC suggest a genetic correlation between T2DM and iRBD (rg=0.306, P=0.029). UVMR analysis indicates that both T2DM (Odds Ratio [95% Confidence Interval] = 1.19 [1.03, 1.37], P = 0.017) and high blood glucose levels (1.55 [1.04, 2.30], P = 0.032) are risk factors for iRBD. Even after adjusting for confounders in MVMR, the association between T2DM and iRBD remains robust. Finally, results from network MR analysis suggest that T2DM may indirectly promote the development of iRBD by reducing levels of Stromal Cell-Derived Factor 2 in circulation and by increasing BAFF-receptor expression in IgD- CD38- B cells.

Conclusions

T2DM may promote the onset of iRBD by influencing immune-inflammatory responses. Our findings provide valuable insights and directions for understanding the pathogenesis of iRBD, identifying high-risk groups, and discovering new therapeutic targets.

The Dual Role of B Cells in the Tumor Microenvironment: Implications for Cancer Immunology and Therapy

The tumor microenvironment (TME) is a complex and heterogeneous tissue composed of various cell types, including tumor cells, stromal cells, and immune cells, as well as non-cellular elements. Given their pivotal role in humoral immunity, B cells have emerged as promising targets for anti-tumor therapies. The dual nature of B cells, exhibiting both tumor-suppressive and tumor-promoting functions, has garnered significant attention. Understanding the distinct effects of various B cell subsets on different tumors could pave the way for novel targeted tumor therapies. This review provides a comprehensive overview of the heterogeneous B cell subsets and their multifaceted roles in tumorigenesis, as well as the therapeutic potential of targeting B cells in cancer treatment. To develop more effective cancer immunotherapies, it is essential to decipher the heterogeneity of B cells and their roles in shaping the TME.

N6-methyladenosine and its epitranscriptomic effects on hematopoietic stem cell regulation and leukemogenesis

N6-methyladenosine (m6A) RNA modification orchestrates cellular epitranscriptome through tuning the homeostasis of transcript stability, translation efficiency, and the transcript affinity toward RNA-binding proteins (RBPs). An aberrant m6A deposition on RNA can lead toward oncogenic expression profile (mRNA), impaired mitochondrial metabolism (mtRNA), and translational suppression (rRNA) of tumor suppressor genes. In addition, non-coding RNAs (ncRNAs), such as X-inactive specific transcript (XIST), miRNAs, and α-ketoglutarate-centric metabolic transcripts are also regulated by the m6A epitranscriptome. Notably, recent studies had uncovered a myriad of m6A-modified transcripts the center of hematopoietic stem cell (HSC) regulation, in which m6A modification act as a context dependent switch to the on and off of hematopoietic stem cell (HSC) maintenance, lineage commitment and terminal differentiation. In this review, we sequentially unfold the m6A mediated epithelial-to-hematopoietic transition in progenitor blood cell production, lymphocytic lineage expansion (T cells, B cells, NK cells, and non-NK ILCs), and the m6A crosstalk with the onco-metabolic prospects of leukemogenesis. Together, an encompassing body of evidence highlighted the emerging m6A significance in the regulation of HSC biology and leukemogenesis.

Mitochondrial Quality Control Orchestrates the Symphony of B Cells and Plays Critical Roles in B Cell-Related Diseases

B cells are essential for humoral immune response due to their ability to secrete antibodies. The development of B cells from the bone marrow to the periphery is tightly regulated by a complex set of immune signals, and each subset of B cells has a unique metabolic profile. Mitochondria, which serve as cellular energy powerhouses, play an essential role in regulating cell survival and immune responses. To maintain metabolic homeostasis, mitochondria dynamically adjust their morphology, distribution, and mass via biogenesis, fusion and fission, translocation, and mitophagy. Despite its extreme importance, the role of mitochondrial quality control (MQC) in B cells has not been thoroughly summarized, unlike in T cells. This article aims to review the mechanism of MQC that shapes B cell fate and functions. In addition, we will discuss the physiological and pathological implications of MQC in B cells, providing new insights into potential therapeutic targets for diseases associated with B cell abnormalities.

Metabolic regulation of the immune system in health and diseases: mechanisms and interventions

Metabolism, including glycolysis, oxidative phosphorylation, fatty acid oxidation, and other metabolic pathways, impacts the phenotypes and functions of immune cells. The metabolic regulation of the immune system is important in the pathogenesis and progression of numerous diseases, such as cancers, autoimmune diseases and metabolic diseases. The concept of immunometabolism was introduced over a decade ago to elucidate the intricate interplay between metabolism and immunity. The definition of immunometabolism has expanded from chronic low-grade inflammation in metabolic diseases to metabolic reprogramming of immune cells in various diseases. With immunometabolism being proposed and developed, the metabolic regulation of the immune system can be gradually summarized and becomes more and more clearer. In the context of many diseases including cancer, autoimmune diseases, metabolic diseases, and many other disease, metabolic reprogramming occurs in immune cells inducing proinflammatory or anti-inflammatory effects. The phenotypic and functional changes of immune cells caused by metabolic regulation further affect and development of diseases. Based on experimental results, targeting cellular metabolism of immune cells becomes a promising therapy. In this review, we focus on immune cells to introduce their metabolic pathways and metabolic reprogramming, and summarize how these metabolic pathways affect immune effects in the context of diseases. We thoroughly explore targets and treatments based on immunometabolism in existing studies. The challenges of translating experimental results into clinical applications in the field of immunometabolism are also summarized. We believe that a better understanding of immune regulation in health and diseases will improve the management of most diseases.

B cells: roles in physiology and pathology of pregnancy

B cells constitute a diverse and adaptable immune cell population with functions that can vary according to the environment and circumstances. The involvement of B cells in pregnancy, as well as the associated molecular pathways, has yet to be investigated. This review consolidates current knowledge on B cell activities and regulation during pregnancy, with a particular focus on the roles of various B cell subsets and the effects of B cell-derived factors on pregnancy outcomes. Moreover, the review examines the significance of B cell-associated autoantibodies, cytokines, and signaling pathways in relation to pregnancy complications such as pregnancy loss, preeclampsia, and preterm birth.

The role of immune cells settled in the bone marrow on adult hematopoietic stem cells

Certain immune cells, including neutrophils, macrophages, dendritic cells, B cells, Breg cells, CD4+ T cells, CD8+ T cells, and Treg cells, establish enduring residency within the bone marrow. Their distinctive interactions with hematopoiesis and the bone marrow microenvironment are becoming increasingly recognized alongside their multifaceted immune functions. These cells play a dual role in shaping hematopoiesis. They directly influence the quiescence, self-renewal, and multi-lineage differentiation of hematopoietic stem and progenitor cells through either direct cell-to-cell interactions or the secretion of various factors known for their immunological functions. Additionally, they actively engage with the cellular constituents of the bone marrow niche, particularly mesenchymal stem cells, endothelial cells, osteoblasts, and osteoclasts, to promote their survival and contribute to tissue repair, thereby fostering a supportive environment for hematopoietic stem and progenitor cells. Importantly, these bone marrow immune cells function synergistically, both locally and functionally, rather than in isolation. In summary, immune cells residing in the bone marrow are pivotal components of a sophisticated network of regulating hematopoiesis.

The interaction of innate immune and adaptive immune system

The innate immune system serves as the body's first line of defense, utilizing pattern recognition receptors like Toll-like receptors to detect pathogens and initiate rapid response mechanisms. Following this initial response, adaptive immunity provides highly specific and sustained killing of pathogens via B cells, T cells, and antibodies. Traditionally, it has been assumed that innate immunity activates adaptive immunity; however, recent studies have revealed more complex interactions. This review provides a detailed dissection of the composition and function of the innate and adaptive immune systems, emphasizing their synergistic roles in physiological and pathological contexts, providing new insights into the link between these two forms of immunity. Precise regulation of both immune systems at the same time is more beneficial in the fight against immune-related diseases, for example, the cGAS-STING pathway has been found to play an important role in infections and cancers. In addition, this paper summarizes the challenges and future directions in the field of immunity, including the latest single-cell sequencing technologies, CAR-T cell therapy, and immune checkpoint inhibitors. By summarizing these developments, this review aims to enhance our understanding of the complexity interactions between innate and adaptive immunity and provides new perspectives in understanding the immune system.

Evaluating 64 Cu-DOTA-rituximab as a PET agent in patients with B-cell lymphoma: a head-to-head comparison with 18 F-fluorodeoxyglucose PET/computed tomography

BACKGROUND

This study aimed to evaluate the biodistribution of 64 Cu-DOTA-rituximab and its diagnostic feasibility for lymphoma using CD20-targeted 64 Cu-DOTA-rituximab PET/computed tomography (PET/CT).

METHODS

A prospective study involving six patients diagnosed with lymphoma was conducted between January 2022 and January 2023. These patients underwent 18 F-fluorodeoxyglucose ( 18 F-FDG) and 64 Cu-DOTA-rituximab PET/CT scans. 64 Cu-DOTA-rituximab PET/CT images were acquired at 1, 24, and 48 h after administering 64 Cu-DOTA-rituximab to assess the biodistribution and dosimetry over time. The observed lymph nodes were categorized into specific regions, including cervical and supraclavicular, axillary and infraclavicular, mediastinal, hilar, abdominal paraaortic and retroperitoneal, iliac, mesenteric, and inguinal regions, to compare the diagnostic ability of 18 F-FDG and 64 Cu-DOTA-rituximab PET/CT in detecting lymphoma lesions. Furthermore, the tumor-to-background ratio was calculated and compared with the maximum standardized uptake (SUV max ) of the tumors and the mean standardized uptake (SUV mean ) of normal organs. Internal radiation dosimetry was determined using the OLINDA/EXM software.

RESULTS

64 Cu-DOTA-rituximab uptake in lymph nodes associated with lymphoma progressively increased from 1 to 48 h after injection. In contrast, 64 Cu-DOTA-rituximab uptake in normal organs, such as blood, lung, kidney, bladder, muscle, bone, and brain, decreased over time, whereas it increased in the liver and spleen. When it comes to the comparison between 64 Cu-DOTA-rituximab and 18 F-FDG, the SUV max of tumors was higher on 64 Cu-DOTA-rituximab PET/CT (18.1 ± 8.3) than on 18 F-FDG PET/CT (5.2 ± 1.5). Additionally, the tumor-to-background ratio, measured using the SUV mean of normal muscles, was higher on 64 Cu-DOTA-rituximab PET/CT (55.7 ± 31.0) than on 18 F-FDG PET/CT (8.6 ± 2.8). No adverse events related to 64 Cu-DOTA-rituximab injection were reported.

CONCLUSION

The results of this study demonstrate the feasibility of using 64 Cu-DOTA-rituximab PET/CT to evaluate the CD20 expression. The increased 64 Cu-DOTA-rituximab uptake in lymph nodes associated with tumors, higher SUV max , and tumor-to-muscle ratios observed with 64 Cu-DOTA-rituximab PET/CT compared with 18 F-FDG PET/CT, highlight the diagnostic potential of this imaging modality.

Research progress on the immunological functions of Piezo1 a receptor molecule that responds to mechanical force

The human immune system is capable of defending against, monitoring, and self-stabilizing various immune cells. Differentiation, proliferation, and development of these cells are regulated by biochemical signals. Moreover, biophysical signals, such as mechanical forces, have been found to affect immune cell function, thus introducing a new area of immunological research. Piezo1, a mechanically sensitive ion channel, was awarded the Nobel Prize for Physiology and Medicine in 2021. This channel is present on the surface of many cells, and when stimulated by mechanical force, it controls calcium (Ca2+) inside the cells, leading to changes in downstream signals and thus regulating cell functions. Piezo1 is also expressed in various innate and adaptive immune cells and plays a major role in the immune function. In this review, we will explore the physiological functions and regulatory mechanisms of Piezo1 and its impact on innate and adaptive immunity. This may offer new insights into diagnostics and therapeutics for the prevention and treatment of diseases and surgical infections.

42-parameter mass cytometry panel to assess cellular and functional phenotypes of leukocytes in bronchoalveolar lavage of Rhesus macaque

This Optimized Multiparameter Immunofluorescence Panel (OMIP) reports on the development of a mass cytometry panel for broad immunophenotyping of leukocytes from bronchoalveolar lavage from rhesus macaques. Using this panel, we were able to identify myeloid populations such as macrophages, neutrophils, monocytes, myeloid and plasmacytoid DCs, basophils and lymphoid cell lineages including B cells, natural killer (NK) cells, mucosal associated invariant T (MAIT) cells, γδ T cells, CD4 T cells, CD8 β T cells, CD8 T cells, and innate lymphoid cells (ILCs). We also included markers for defining memory, differentiation (CCR7, CD28, CD45RA), homing potential (CXCR3), cytotoxic potential (perforin, granzyme B, granzyme K), cell activation/differentiation (HLA-DR, CD69, IgD) and effector function (CD154, IFN-γ, TNF, IL-2, IL-17A, IL-6, IL-1β, CCL4 and CD107a). This panel was optimized on cryopreserved, bronchoalveolar lavage and splenocytes collected from rhesus macaques. The antibodies selected in this panel are human-specific antibodies that have been shown to cross-react with non-human primates except for CD45 clone D058-1283 which is specific for non-human primates.

The current understanding of the phenotypic and functional properties of human regulatory B cells (Bregs)

B cells can have a wide range of pro- and anti- inflammatory functions. A subset of B cells called regulatory B cells (Bregs) can potently suppress immune responses. Bregs have been shown to maintain immune homeostasis and modulate inflammatory responses. Bregs are an exciting cellular target across a range of diseases, including Breg induction in autoimmunity, allergy and transplantation, and Breg suppression in cancers and infection. Bregs exhibit a remarkable phenotypic heterogeneity, rendering their unequivocal identification a challenging task. The lack of a universally accepted and exclusive surface marker set for Bregs across various studies contributes to inconsistencies in their categorization. This review paper presents a comprehensive overview of the current understanding of the phenotypic and functional properties of human Bregs while addressing the persisting ambiguities and discrepancies in their characterization. Finally, the paper examines the promising therapeutic opportunities presented by Bregs as their immunomodulatory capacities have gained attention in the context of autoimmune diseases, allergic conditions, and cancer. We explore the exciting potential in harnessing Bregs as potential therapeutic agents and the avenues that remain open for the development of Breg-based treatment strategies.

Reconstitution of the Multiple Myeloma Microenvironment Following Lymphodepletion with BCMA CAR-T Therapy

PURPOSE

The purpose of this study was to investigate the remodeling of the multiple myeloma microenvironment after B-cell maturation antigen (BCMA)-targeted chimeric antigen receptor T (CAR-T) cell therapy.

EXPERIMENTAL DESIGN

We performed single-cell RNA sequencing on paired bone marrow specimens (n = 14) from seven patients with multiple myeloma before (i.e., baseline, "day -4") and after (i.e., "day 28") lymphodepleted BCMA CAR-T cell therapy.

RESULTS

Our analysis revealed heterogeneity in gene expression profiles among multiple myeloma cells, even those harboring the same cytogenetic abnormalities. The best overall responses of patients over the 15-month follow-up are positively correlated with the abundance and targeted cytotoxic activity of CD8+ effector CAR-T cells on day 28 after CAR-T cell infusion. Additionally, favorable responses are associated with attenuated immunosuppression mediated by regulatory T cells, enhanced CD8+ effector T-cell cytotoxic activity, and elevated type 1 conventional dendritic cell (DC) antigen presentation ability. DC re-clustering inferred intramedullary-originated type 3 conventional DCs with extramedullary migration. Cell-cell communication network analysis indicated that BCMA CAR-T therapy mitigates BAFF/GALECTIN/MK pathway-mediated immunosuppression and activates MIF pathway-mediated anti-multiple myeloma immunity.

CONCLUSIONS

Our study sheds light on multiple myeloma microenvironment dynamics after BCMA CAR-T therapy, offering clues for predicting treatment responsivity.

Characterization of unique B-cell populations in the circulation of people living with HIV prior to non-Hodgkin lymphoma diagnosis

People living with HIV (PLWH) are at higher risk of developing lymphoma. In this study, we performed cytometry by time-of-flight (CyTOF) on peripheral blood mononuclear cells of cART-naïve HIV+ individuals and cART-naïve HIV+ individuals prior to AIDS-associated non-Hodgkin lymphoma (pre-NHL) diagnosis. Participants were enrolled in the Los Angeles site of the MACS/WIHS Combined Cohort Study (MWCCS). Uniform Manifold Approximation and Projection (UMAP) and unsupervised clustering analysis were performed to identify differences in the expression of B-cell activation markers and/or oncogenic markers associated with lymphomagenesis. CD10+CD27- B cells, CD20+CD27- B cells, and B-cell populations with aberrant features (CD20+CD27+CXCR4+CD71+ B cells and CD20+CXCR4+cMYC+ B cells) were significantly elevated in HIV+ cART-naïve compared to HIV-negative samples. CD20+CD27+CD24+CXCR4+CXCR5+ B cells, CD20+CD27+CD10+CD24+CXCR4+cMYC+ B cells, and a cluster of CD20+CXCR4hiCD27-CD24+CXCR5+CD40+CD4+AICDA+ B cells were significantly elevated in HIV+ pre-NHL (cART-naïve) compared to HIV+ cART-naïve samples. A potentially clonal cluster of CD20+CXCR4+CXCR5+cMYC+AICDA+ B cells and a cluster of germinal center B-cell-like cells (CD19-CD20+CXCR4+Bcl-6+PD-L1+cMYC+) were also found in the circulation of HIV+ pre-NHL (cART-naïve) samples. Moreover, significantly elevated clusters of CD19+CD24hiCD38hi cMYC+ AICDA+ B regulatory cells were identified in HIV+ pre-NHL (cART-naïve) compared to HIV+ cART-naïve samples. The present study identifies unique B-cell subsets in PLWH with potential pre-malignant features that may contribute to the development of pre-tumor B cells in PLWH and that may play a role in lymphomagenesis.

Effect of inferior caval valve implantation on circulating immune cells and inflammatory mediators in severe tricuspid regurgitation

BACKGROUND

Interventional valve implantation into the inferior vena cava (CAVI) lowers venous congestion in patients with tricuspid regurgitation (TR). We evaluated the impact of a reduction of abdominal venous congestion following CAVI on circulating immune cells and inflammatory mediators.

METHODS

Patients with severe TR were randomized to optimal medical therapy (OMT) + CAVI (n = 8) or OMT (n = 10). In the OMT + CAVI group, an Edwards Sapien XT valve was implanted into the inferior vena cava. Immune cells and inflammatory mediators were measured in the peripheral blood at baseline and three-month follow-up.

RESULTS

Leukocytes, monocytes, basophils, eosinophils, neutrophils, lymphocytes, B, T and natural killer cells and inflammatory markers (C-reactive protein, interferon-gamma, interleukin-2, -4, -5, -10, and tumor necrosis factor-alpha) did not change substantially between baseline and three-month follow-up within the OMT + CAVI and OMT group.

CONCLUSION

The present data suggest that reduction of venous congestion following OMT + CAVI may not lead to substantial changes in systemic inflammation within a short-term follow-up.

CLINICAL TRIAL REGISTRATION

NCT02387697.

Regulation of immune cells by miR-451 and its potential as a biomarker in immune-related disorders: a mini review

In 2005, Altuvia and colleagues were the first to identify the gene that encodes miR-451 in the human pituitary gland, located in chromosome region 17q11.2. Subsequent studies have confirmed that miR-451 regulates various immune cells, including T cells, B cells, microglia, macrophages, and neutrophils, thereby influencing disease progression. The range of immune-related diseases affected encompasses various cancers, lymphoblastic leukemia, and injuries to the lungs and spinal cord, among others. Moreover, miR-451 is produced by immune cells and can regulate both their own functions and those of other immune cells, thus creating a regulatory feedback loop. This article aims to comprehensively review the interactions between miR-451 and immune cells, clarify the regulatory roles of miR-451 within the immune system, and assess its potential as both a therapeutic target and a biomarker for immune-related diseases.

B-cell hub genes play a cardiovascular pathogenic role of in childhood obesity and Kawasaki disease as revealed by transcriptomics-based analyses

The study aims to explore the central genes that Kawasaki disease (KD) and Obesity (OB) may jointly contribute to coronary artery disease. Investigating single-cell datasets (GSE168732 and GSE163830) from a comprehensive gene expression database, we identified characteristic immune cell subpopulations in KD and OB. B cells emerged as the common immune cell characteristic subgroup in both conditions. Subsequently, we analyzed RNA sequencing datasets (GSE18606 and GSE87493) to identify genes associated with B-cell subpopulations in KD and OB. Lastly, a genome-wide association study and Mendelian randomization were conducted to substantiate the causal impact of these core genes on myocardial infarction. Quantitative real-time PCR (qRT-PCR) to validate the expression levels of hub genes in KD and OB. The overlapping characteristic genes of B cell clusters in both KD and OB yielded 70 shared characteristic genes. PPI analysis led to the discovery of eleven key genes that significantly contribute to the crosstalk. Employing receiver operating characteristic analysis, we evaluated the specificity and sensitivity of these core genes and scored them using Cytoscape software. The inverse variance weighting analysis suggested an association between TNFRSF17 and myocardial infarction risk, with an odds ratio of 0.9995 (95% CI = 0.9990-1.0000, p = 0.049). By employing a single-cell combined transcriptome data analysis, we successfully pinpointed central genes associated with both KD and OB. The implications of these findings extend to shedding light on the increased risk of coronary artery disease resulting from the co-occurrence of OB and KD.

Detection of disease-specific signatures in B cell repertoires of lymphomas using machine learning

The classification of B cell lymphomas-mainly based on light microscopy evaluation by a pathologist-requires many years of training. Since the B cell receptor (BCR) of the lymphoma clonotype and the microenvironmental immune architecture are important features discriminating different lymphoma subsets, we asked whether BCR repertoire next-generation sequencing (NGS) of lymphoma-infiltrated tissues in conjunction with machine learning algorithms could have diagnostic utility in the subclassification of these cancers. We trained a random forest and a linear classifier via logistic regression based on patterns of clonal distribution, VDJ gene usage and physico-chemical properties of the top-n most frequently represented clonotypes in the BCR repertoires of 620 paradigmatic lymphoma samples-nodular lymphocyte predominant B cell lymphoma (NLPBL), diffuse large B cell lymphoma (DLBCL) and chronic lymphocytic leukemia (CLL)-alongside with 291 control samples. With regard to DLBCL and CLL, the models demonstrated optimal performance when utilizing only the most prevalent clonotype for classification, while in NLPBL-that has a dominant background of non-malignant bystander cells-a broader array of clonotypes enhanced model accuracy. Surprisingly, the straightforward logistic regression model performed best in this seemingly complex classification problem, suggesting linear separability in our chosen dimensions. It achieved a weighted F1-score of 0.84 on a test cohort including 125 samples from all three lymphoma entities and 58 samples from healthy individuals. Together, we provide proof-of-concept that at least the 3 studied lymphoma entities can be differentiated from each other using BCR repertoire NGS on lymphoma-infiltrated tissues by a trained machine learning model.

B-cell performance in chemotherapy: Unravelling the mystery of B-cell therapeutic potential

BACKGROUND AND MAIN BODY

The anti-tumour and tumour-promoting roles of B cells in the tumour microenvironment (TME) have gained considerable attention in recent years. As essential orchestrators of humoral immunity, B cells potentially play a crucial role in anti-tumour therapies. Chemotherapy, a mainstay in cancer treatment, influences the proliferation and function of diverse B-cell subsets and their crosstalk with the TME. Modulating B-cell function by targeting B cells or their associated cells may enhance chemotherapy efficacy, presenting a promising avenue for future targeted therapy investigations.

CONCLUSION

This review explores the intricate interplay between chemotherapy and B cells, underscoring the pivotal role of B cells in chemotherapy treatment. We summarise promising B-cell-related therapeutic targets, illustrating the immense potential of B cells in anti-tumour therapy. Our work lays a theoretical foundation for harnessing B cells in chemotherapy and combination strategies for cancer treatment.

KEY POINTS

Chemotherapy can inhibit B-cell proliferation and alter subset distributions and functions, including factor secretion, receptor signalling, and costimulation. Chemotherapy can modulate complex B-cell-T-cell interactions with variable effects on anti-tumour immunity. Targeting B-cell surface markers or signalling improves chemotherapy responses, blocks immune evasion and inhibits tumour growth. Critical knowledge gaps remain regarding B-cell interactions in TME, B-cell chemoresistance mechanisms, TLS biology, heterogeneity, spatial distributions, chemotherapy drug selection and B-cell targets that future studies should address.

Profiles of peripheral B cell subsets in a cohort of primary Sjögren's syndrome patients and their potential clinical significance

Background/purpose

Primary Sjögren's syndrome is a prototypical autoimmune disease, with B cell dysfunction as a dominant feature. Further insights into distribution of B cell subsets in primary Sjögren's syndrome are urgently required to identify the most appropriate target subpopulation. We aimed to evaluate the profiles of B lymphocyte subpopulations in primary Sjögren's syndrome patients and to investigate their clinical significance.

Materials and methods

Thirty primary Sjögren's syndrome patients and 15 age-and sex-matched healthy controls were recruited. Peripheral B cell subsets were analyzed by flow cytometry.

Results

Compared to healthy controls, circulating CD19+ B cells, CD19+CD20- B cells, CD19+CD27-IgD+ naïve B cells, CD19+IgD+CD38high plasmablasts, CD19+CD24highCD38high transitional B cells and CD19+CD20-CD27+CD38+ plasma cells were elevated in patients with primary Sjögren's syndrome, whereas CD19+CD27+ memory B cells, CD19+CD27-IgD- double negative B cells and CD19+CD24hiCD27+ Bregs were decreased. Furthermore, the percentage of circulating CD19+CD20-CD27+CD38+ plasma cells was positively correlated with serum IgG levels and the proportional area of lymphocytic infiltration of labial gland.

Conclusion

We identified a comprehensive B lymphocyte subset distribution profile in primary Sjögren's syndrome. Moreover, we detected a clinical significance of CD19+CD20-CD27+CD38+ plasma cells, suggesting that these cells might play a key role in disease pathology and represent potential therapeutic targets.

Optimization of preparation method and specificity verification of cat CD19 monoclonal antibody for disease diagnosis and treatment

CD19 is a surface antigen on B cells that regulates B cell activation and proliferation, participating in B cell signaling. It is expressed in all B cell lineage tumor diseases, making CD19 a significant marker for detecting B cell tumor diseases and an important target for related immunotherapies. In recent years, with the deepening research on canine and feline diseases and the establishment of animal models, the demand for cat CD19 monoclonal antibodies (mAbs) has been steadily increasing. We successfully prepared cat CD19-specific monoclonal antibodies using a KLH-conjugated cat CD19 peptide as an antigen and optimized the antibody production method. The obtained monoclonal antibodies' molecular and cellular affinities were identified using CD19 peptides, eukaryotic overexpressed proteins, and peripheral blood mononuclear cells (PBMCs). The results indicate that the CD19-3H9 and CD19-8A7 monoclonal antibodies prepared in this study specifically bind to the CD19 molecule, demonstrating their suitability for use in ELISA, Western blot, and cell assays. This study successfully produced cat CD19 monoclonal antibodies with specificity and optimized the antibody preparation method, laying the foundation for the diagnosis and targeted drug combination therapy of B cell tumor diseases in both humans and pets.

Adaptive Cellular Responses following SARS-CoV-2 Vaccination in Primary Antibody Deficiency Patients

Since the start of the COVID-19 pandemic, in a short span of 3 years, vaccination against SARS-CoV-2 has resulted in the end of the pandemic. Patients with inborn errors of immunity (IEI) are at an increased risk for SARS-CoV-2 infection; however, serious illnesses and mortality, especially in primary antibody deficiencies (PADs), have been lower than expected and lower than other high-risk groups. This suggests that PAD patients may mount a reasonable effective response to the SARS-CoV-2 vaccine. Several studies have been published regarding antibody responses, with contradictory reports. The current study is, perhaps, the most comprehensive study of phenotypically defined various lymphocyte populations in PAD patients following the SARS-CoV-2 vaccine. In this study, we examined, following two vaccinations and, in a few cases, prior to and following the 1st and 2nd vaccinations, subsets of CD4 and CD8 T cells (Naïve, TCM, TEM, TEMRA), T follicular helper cells (TFH1, TFH2, TFH17, TFH1/17), B cells (naïve, transitional, marginal zone, germinal center, IgM memory, switched memory, plasmablasts, CD21low), regulatory lymphocytes (CD4Treg, CD8Treg, TFR, Breg), and SARS-CoV-2-specific activation of CD4 T cells and CD8 T cells (CD69, CD137), SARS-CoV-2 tetramer-positive CD8 T cells, and CD8 CTL. Our data show significant alterations in various B cell subsets including Breg, whereas only a few subsets of various T cells revealed alterations. These data suggest that large proportions of PAD patients may mount significant responses to the vaccine.

Characterization of dUTPase expression in mouse postnatal development and adult neurogenesis

The enzyme dUTPase has an essential role in maintaining genomic integrity. In mouse, nuclear and mitochondrial isoforms of the enzyme have been described. Here we present the isoform-specific mRNA expression levels in different murine organs during development using RT-qPCR. In this study, we analyzed organs of 14.5-day embryos and of postnatal 2-, 4-, 10-week- and 13-month-old mice. We demonstrate organ-, sex- and developmental stage-specific differences in the mRNA expression levels of both isoforms. We found high mRNA expression level of the nuclear isoform in the embryo brain, and the expression level remained relatively high in the adult brain as well. This was surprising, since dUTPase is known to play an important role in proliferating cells, and mass production of neural cells is completed by adulthood. Thus, we investigated the pattern of the dUTPase protein expression specifically in the adult brain with immunostaining and found that dUTPase is present in the germinative zones, the subventricular and the subgranular zones, where neurogenesis occurs and in the rostral migratory stream where neuroblasts migrate to the olfactory bulb. These novel findings suggest that dUTPase may have a role in cell differentiation and indicate that accurate dTTP biosynthesis can be vital, especially in neurogenesis.

Fluoxetine Successfully Treats Intracranial Enterovirus E18 Infection in a Patient with CD79a Deficiency Arising from Segmental Uniparental Disomy of Chromosome 19

The pre BCR complex plays a crucial role in B cell production, and its successful expression marks the B cell differentiation from the pro-B to pre-B. The CD79a and CD79b mutations, encoding Igα and Igβ respectively, have been identified as the cause of autosomal recessive agammaglobulinemia (ARA). Here, we present a case of a patient with a homozygous CD79a mutation, exhibiting recurrent respiratory infections, diarrhea, growth and development delay, unique facial abnormalities and microcephaly, as well as neurological symptoms including tethered spinal cord, sacral canal cyst, and chronic enteroviral E18 meningitis. Complete blockade of the early B cell development in the bone marrow of the patient results in the absence of peripheral circulating mature B cells. Whole exome sequencing revealed a Loss of Heterozygosity (LOH) of approximately 19.20Mb containing CD79a on chromosome 19 in the patient. This is the first case of a homozygous CD79a mutation caused by segmental uniparental diploid (UPD). Another key outcome of this study is the effective management of long-term chronic enteroviral meningitis using a combination of intravenous immunoglobulin (IVIG) and fluoxetine. This approach offers compelling evidence of fluoxetine's utility in treating enteroviral meningitis, particularly in immunocompromised patients.

Hormones and B-cell development in health and autoimmunity

The development of B cells into antibody-secreting plasma cells is central to the adaptive immune system as they induce protective and specific antibody responses against invading pathogens. Various studies have shown that, during this process, hormones can play important roles in the lymphopoiesis, activation, proliferation, and differentiation of B cells, and depending on the signal given by the receptor of each hormone, they can have a positive or negative effect. In autoimmune diseases, hormonal deregulation has been reported to be related to the survival, activation and/or differentiation of autoreactive clones of B cells, thus promoting the development of autoimmunity. Clinical manifestations of autoimmune diseases have been associated with estrogens, prolactin (PRL), and growth hormone (GH) levels. However, androgens, such as testosterone and progesterone (P4), could have a protective effect. The objective of this review is to highlight the links between different hormones and the immune response mediated by B cells in the etiopathogenesis of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and multiple sclerosis (MS). The data collected provide insights into the role of hormones in the cellular, molecular and/or epigenetic mechanisms that modulate the B-cell response in health and disease.

B cell development and antibody responses in human immune system mice: current status and future perspective

Humanized immune system (HIS) mice have been developed and used as a small surrogate model to study human immune function under normal or disease conditions. Although variations are found between models, most HIS mice show robust human T cell responses. However, there has been unsuccessful in constructing HIS mice that produce high-affinity human antibodies, primarily due to defects in terminal B cell differentiation, antibody affinity maturation, and development of primary follicles and germinal centers. In this review, we elaborate on the current knowledge about and previous attempts to improve human B cell development in HIS mice, and propose a potential strategy for constructing HIS mice with improved humoral immunity by transplantation of human follicular dendritic cells (FDCs) to facilitate the development of secondary follicles.

The trajectory of human B-cell function, immune deficiency, and allergy revealed by inborn errors of immunity

The essential role of B cells is to produce protective immunoglobulins (Ig) that recognize, neutralize, and clear invading pathogens. This results from the integration of signals provided by pathogens or vaccines and the stimulatory microenvironment within sites of immune activation, such as secondary lymphoid tissues, that drive mature B cells to differentiate into memory B cells and antibody (Ab)-secreting plasma cells. In this context, B cells undergo several molecular events including Ig class switching and somatic hypermutation that results in the production of high-affinity Ag-specific Abs of different classes, enabling effective pathogen neutralization and long-lived humoral immunity. However, perturbations to these key signaling pathways underpin immune dyscrasias including immune deficiency and autoimmunity or allergy. Inborn errors of immunity that disrupt critical immune pathways have identified non-redundant requirements for eliciting and maintaining humoral immune memory but concomitantly prevent immune dysregulation. Here, we will discuss our studies on human B cells, and how our investigation of cytokine signaling in B cells have identified fundamental requirements for memory B-cell formation, Ab production as well as regulating Ig class switching in the context of protective versus allergic immune responses.

Granzyme B+ B cells detected by single-cell sequencing are associated with prognosis in patients with intrahepatic cholangiocarcinoma following liver transplantation

B cells possess anti-tumor functions mediated by granzyme B, in addition to their role in antigen presentation and antibody production. However, the variations in granzyme B+ B cells between tumor and non-tumor tissues have been largely unexplored. Therefore, we integrated 25 samples from the Gene Expression Omnibus database and analyzed the tumor immune microenvironment. The findings uncovered significant inter- and intra-tumoral heterogeneity. Notably, single-cell data showed higher proportions of granzyme B+ B cells in tumor samples compared to control samples, and these levels were positively associated with disease-free survival. The elevated levels of granzyme B+ B cells in tumor samples resulted from tumor cell chemotaxis through the MIF- (CD74 + CXCR4) signaling pathway. Furthermore, the anti-tumor function of granzyme B+ B cells in tumor samples was adversely affected, potentially providing an explanation for tumor progression. These findings regarding granzyme B+ B cells were further validated in an independent clinic cohort of 40 liver transplant recipients with intrahepatic cholangiocarcinoma. Our study unveils an interaction between granzyme B+ B cells and intrahepatic cholangiocarcinoma, opening up potential avenues for the development of novel therapeutic strategies against this disease.

Unraveling the Role of the NLRP3 Inflammasome in Lymphoma: Implications in Pathogenesis and Therapeutic Strategies

Inflammasomes are multimeric protein complexes, sensors of intracellular danger signals, and crucial components of the innate immune system, with the NLRP3 inflammasome being the best characterized among them. The increasing scientific interest in the mechanisms interconnecting inflammation and tumorigenesis has led to the study of the NLRP3 inflammasome in the setting of various neoplasms. Despite a plethora of data regarding solid tumors, NLRP3 inflammasome's implication in the pathogenesis of hematological malignancies only recently gained attention. In this review, we investigate its role in normal lymphopoiesis and lymphomagenesis. Considering that lymphomas comprise a heterogeneous group of hematologic neoplasms, both tumor-promoting and tumor-suppressing properties were attributed to the NLRP3 inflammasome, affecting neoplastic cells and immune cells in the tumor microenvironment. NLRP3 inflammasome-related proteins were associated with disease characteristics, response to treatment, and prognosis. Few studies assess the efficacy of NLRP3 inflammasome therapeutic targeting with encouraging results, though most are still at the preclinical level. Further understanding of the mechanisms regulating NLRP3 inflammasome activation during lymphoma development and progression can contribute to the investigation of novel treatment approaches to cover unmet needs in lymphoma therapeutics.

Microfluidic-assisted single-cell RNA sequencing facilitates the development of neutralizing monoclonal antibodies against SARS-CoV-2

As a class of antibodies that specifically bind to a virus and block its entry, neutralizing monoclonal antibodies (neutralizing mAbs) have been recognized as a top choice for combating COVID-19 due to their high specificity and efficacy in treating serious infections. Although conventional approaches for neutralizing mAb development have been optimized for decades, there is an urgent need for workflows with higher efficiency due to time-sensitive concerns, including the high mutation rate of SARS-CoV-2. One promising approach is the identification of neutralizing mAb candidates via single-cell RNA sequencing (RNA-seq), as each B cell has a unique transcript sequence corresponding to its secreted antibody. The state-of-the-art high-throughput single-cell sequencing technologies, which have been greatly facilitated by advances in microfluidics, have greatly accelerated the process of neutralizing mAb development. Here, we provide an overview of the general procedures for high-throughput single-cell RNA-seq enabled by breakthroughs in droplet microfluidics, introduce revolutionary approaches that combine single-cell RNA-seq to facilitate the development of neutralizing mAbs against SARS-CoV-2, and outline future steps that need to be taken to further improve development strategies for effective treatments against infectious diseases.

Molecular complexity of diffuse large B-cell lymphoma: a molecular perspective and therapeutic implications

Diffuse large B-cell lymphoma (DLBCL) stands as a formidable challenge in the landscape of non-Hodgkin's lymphomas. This review illuminates the remarkable strides made in comprehending DLBCL's molecular intricacies and devising targeted treatments. DLBCL, the most prevalent non-Hodgkin's lymphoma, has seen transformative progress in its characterization. Genetic investigations, led by high-throughput sequencing, have unveiled recurrent mutations in genes such as MYC, BCL2, and BCL6, casting light on the underlying genetic chaos propelling DLBCL's aggressiveness. A pivotal facet of this understanding centers on cell signaling pathways. Dysregulation of B-cell receptor (BCR) signaling, NF-κB, PI3K/Akt/mTOR, JAK/STAT, Wnt/β-Catenin, and Toll-like receptor pathways plays a critical role in DLBCL pathogenesis, offering potential therapeutic targets. DLBCL's complex tumor microenvironment (TME) cannot be overlooked. The dynamic interplay among tumor cells, immune cells, stromal components, and the extracellular matrix profoundly influences DLBCL's course and response to therapies. Epigenetic modifications, including DNA methylation and histone changes, add another layer of intricacy. Aberrant epigenetic regulation plays a significant role in lymphomagenesis, offering prospects for epigenetic-based therapies. Promisingly, these molecular insights have spurred the development of personalized treatments. Targeted therapies and immunotherapies, guided by genomic profiling and molecular classification, are emerging as game-changers in DLBCL management. In conclusion, this review underscores the remarkable strides in understanding DLBCL's molecular underpinnings, spanning genetics, cell signaling, the tumor microenvironment, and epigenetics. These advances pave the way for more effective, personalized treatments, renewing hope for DLBCL patients.