The early history of B cells

Mitochondrial control of lymphocyte homeostasis

Mitochondria play a multitude of essential roles within mammalian cells, and understanding how they control immunity is an emerging area of study. Lymphocytes, as integral cellular components of the adaptive immune system, rely on mitochondria for their function, and mitochondria can dynamically instruct their differentiation and activation by undergoing rapid and profound remodelling. Energy homeostasis and ATP production are often considered the primary functions of mitochondria in immune cells; however, their importance extends across a spectrum of other molecular processes, including regulation of redox balance, signalling pathways, and biosynthesis. In this review, we explore the dynamic landscape of mitochondrial homeostasis in T and B cells, and discuss how mitochondrial disorders compromise adaptive immunity.

Subtractive proteomics-based vaccine targets annotation and reverse vaccinology approaches to identify multiepitope vaccine against Plesiomonas shigelloides

Plesiomonas shigelloides, an aquatic bacterium belonging to the Enterobacteriaceae family, is a frequent cause of gastroenteritis with diarrhea and gastrointestinal severe disease. Despite decades of research, discovering a licensed and globally accessible vaccine is still years away. Developing a putative vaccine that can combat the Plesiomonas shigelloides infection by boosting population immunity against P. shigelloides is direly needed. In the framework of the current study, the entire proteome of P. shigelloides was explored using subtractive genomics integrated with the immunoinformatics approach for designing an effective vaccine construct against P. shigelloides. The overall stability of the vaccine construct was evaluated using molecular docking, which demonstrated that MEV showed higher binding affinities with toll-like receptors (TLR4: 51.5 ± 10.3, TLR2: 60.5 ± 9.2) and MHC receptors(MHCI: 79.7 ± 11.2 kcal/mol, MHCII: 70.4 ± 23.7). Further, the therapeutic efficacy of the vaccine construct for generating an efficient immune response was evaluated by computational immunological simulation. Finally, computer-based cloning and improvement in codon composition without altering amino acid sequence led to the development of a proposed vaccine. In a nutshell, the findings of this study add to the existing knowledge about the pathogenesis of this infection. The schemed MEV can be a possible prophylactic agent for individuals infected with P. shigelloides. Nevertheless, further authentication is required to guarantee its safeness and immunogenic potential.

Causal Relationship Between Circulating Immune Cells and Recurrent Spontaneous Abortion: A Bidirectional Mendelian Randomization Study

BACKGROUND

Recurrent spontaneous abortion (RSA) is a serious and common complication of pregnancy caused by multiple factors. The etiology remains incompletely understood, but immunologic factors play important roles. Here, we aimed to evaluate whether circulating immune cells causally impacted RSA.

METHODS

In this study, we conducted a comprehensive two-sample Mendelian randomization (MR) study to determine the causal association between the 731 immunophenotypes of human peripheral blood lymphocytes and the number of spontaneous abortions as well as recurrent miscarriage. Sensitivity analyses were performed to assess and minimize heterogeneity and horizontal pleiotropy. Reverse MR analysis was used to assess reverse causality.

RESULTS

After Bonferroni-correction, eight immunophenotypes were significantly associated with the number of spontaneous abortions: FSC-A on CD4+ T cell (beta = -0.051, 95% CI = [-0.085, -0.017], P-value = 0.004), CD8 on HLA DR+ CD8+ T cell (beta = -0.040, 95% CI = [-0.067, -0.014], P-value = 0.003), HLA DR on CD33dim HLA DR+ CD11b- (beta = -0.021, 95% CI = [-0.036, -0.005], P-value = 0.010), HLA DR+ T cell Absolute Count (beta = 0.022, 95% CI = [0.006, 0.037], P-value = 0.008), HLA DR+ T cell % lymphocyte (beta = 0.026, 95% CI = [0.010, 0.041], P-value = 0.001), HLA DR+ T cell % T cell (beta = 0.023, 95% CI = [0.007, 0.039], P-value = 0.004), HLA DR+ CD4+ T cell % lymphocyte (beta = 0.034, 95% CI = [0.007, 0.060], P-value = 0.012), and HLA DR on B cell (beta = 0.012, 95% CI = [0.003, 0.021], P-value = 0.010). In addition, we identified two immunophenotypes associated with recurrent miscarriage: HLA DR on B cell (OR = 0.854, 95% CI = [0.757, 0.964], P-value = 0.011), and CD19 on naive-mature B cell (OR = 4.595, 95% CI = [1.674, 12.617], P-value = 0.003). There was no evidence of heterogeneity, horizontal pleiotropy and reverse causality.

CONCLUSIONS

Our study demonstrated a tight link between adaptive immune cells and RSA through genetic means, thus providing potential therapeutic targets or novel diagnostic biomarkers.

Principles and therapeutic applications of adaptive immunity

Adaptive immunity provides protection against infectious and malignant diseases. These effects are mediated by lymphocytes that sense and respond with targeted precision to perturbations induced by pathogens and tissue damage. Here, we review key principles underlying adaptive immunity orchestrated by distinct T cell and B cell populations and their extensions to disease therapies. We discuss the intracellular and intercellular processes shaping antigen specificity and recognition in immune activation and lymphocyte functions in mediating effector and memory responses. We also describe how lymphocytes balance protective immunity against autoimmunity and immunopathology, including during immune tolerance, response to chronic antigen stimulation, and adaptation to non-lymphoid tissues in coordinating tissue immunity and homeostasis. Finally, we discuss extracellular signals and cell-intrinsic programs underpinning adaptive immunity and conclude by summarizing key advances in vaccination and engineering adaptive immune responses for therapeutic interventions. A deeper understanding of these principles holds promise for uncovering new means to improve human health.

Optimising IL-2 for Cancer Immunotherapy

The key role of T cells in cancer immunotherapy is well established and is highlighted by the remarkable capacity of Ab-mediated checkpoint blockade to overcome T-cell exhaustion and amplify anti-tumor responses. However, total or partial tumor remission following checkpoint blockade is still limited to only a few types of tumors. Hence, concerted attempts are being made to devise new methods for improving tumor immunity. Currently, much attention is being focused on therapy with IL-2. This cytokine is a powerful growth factor for T cells and optimises their effector functions. When used at therapeutic doses for cancer treatment, however, IL-2 is highly toxic. Nevertheless, recent work has shown that modifying the structure or presentation of IL-2 can reduce toxicity and lead to effective anti-tumor responses in synergy with checkpoint blockade. Here, we review the complex interaction of IL-2 with T cells: first during normal homeostasis, then during responses to pathogens, and finally in anti-tumor responses.

Computational Analysis of B-Cell Receptor (BCR) Immune Repertoires with Abalign

The widespread application of high-throughput sequencing technology has generated massive sequences of B-cell receptor (BCR) immune repertoires. Computational analysis of these data has gained significant attention due to the increasing importance of immunotherapy and precision medicine. It not only reveals the diversity and dynamic changes in immune responses, contributing to the study of associated diseases, but also provides valuable information for immunodiagnostics and drug development. Recently, we introduced a BCR-specific multiple sequence alignment (MSA) method along with a comprehensive platform software called Abalign, which stands out as an excellent choice for analyzing BCR immune repertoires due to its unique high-throughput processing capability. It offers ultra-fast MSA functionality and a wide range of analytical features, including BCR/antibody extraction, clonal grouping, lineage tree construction, mutation profiling, diversity statistics, VJ gene assignment, antibody humanization, and more. Importantly, users can perform these analyses using the graphical user interface without any programming skills or scripts. In this article, we present a series of protocols that integrate Abalign's analysis modules into a cohesive workflow. This step-by-step workflow provides detailed instructions for software installation, data preparation, and comprehensive analysis of BCR immune repertoires. This workflow facilitates the efficient acquisition of comprehensive results in profiling BCR immune repertoires, offering insights into the impacts of infectious diseases, allergies, autoimmune disorders, tumor immunology, and antibody drugs. Abalign is freely available at http://cao.labshare.cn/abalign/. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Resource preparation Basic Protocol 2: Analyzing BCR immune repertoires Support Protocol 1: Aiding antibody humanization Support Protocol 2: Constructing B-cell lineage trees Alternate Protocol: Running with Linux command line Basic Protocol 3: Comparing BCR immune repertoires.

Transcriptomic evaluation of N6-methyladenosine modification can be used to identify differentially gene and immune-related biological processes in TX mice with liver fibrosis

BACKGROUND

N6-methyladenosine (m6A) modification controls the stability, splicing, and translation of mRNA, which is important in the development of illnesses. Wilson's disease (WD) is an autosomal recessive liver copper metabolic disorder that causes liver fibrosis. The role of m6A methylation in WD-induced liver fibrosis development is still unclear. Thus, the goal of this study was to examine the scope of m6A methylation and further explore the potential targets related to WD-induced liver fibrosis.

RESULTS

A total of 1930 significantly different m6A peaks were found on 1737 mRNAs, of which 993 were hypermethylated and 744 were hypomethylated when comparing normal and WD-induced liver fibrosis mice (n = 3). In parallel, 1261 differentially expressed mRNAs, comprising 557 upregulated and 704 downregulated mRNAs, were found. Overall, 114 mRNAs with significant changes in m6A levels and RNA expression were identified via joint analysis. Then, through PPI network construction and functional enrichment analysis, 12 hub genes were identified, these genes were mainly enriched in the inflammatory response and immunomodulation, and they are associated with immune cell infiltration.

CONCLUSIONS

The significant difference in the amount of mRNA m6A modifications indicates that m6A modification is involved in the progression of WD-induced liver fibrosis, and theidentified hub genes are involved in inflammation and immune infiltration. These results may provide insights for subsequent studies on potential regulatory mechanisms.

Dysregulation of B lymphocyte development in the SKG mouse model of rheumatoid arthritis

Rheumatoid arthritis is a chronic and systemic inflammatory disease that affects approximately 1% of the world's population and is characterised by joint inflammation, the destruction of articular cartilage and bone, and many potentially life-threatening extraarticular manifestations. B lymphocytes play a central role in the pathology of rheumatoid arthritis as the precursors of autoantibody secreting plasma cells, as highly potent antigen-presenting cells, and as a source of various inflammatory cytokines, however, the effects of rheumatoid arthritis on B lymphocyte development remain poorly understood. Here, we analyse B lymphocyte development in murine models of rheumatoid arthritis, quantifying all the subsets of B cell precursors in the bone marrow and splenic B cells using flow cytometry. We demonstrate a severe reduction in pre-B cells and immature B cells in the bone marrow of mice with active disease, despite no major effects on the mature naïve B cell numbers. The loss of B cell precursors in the bone marrow of the affected mice was associated with a highly significant reduction in the proportion of Ki67+ cells, indicating impaired cell proliferation, while the viability of the B cell precursors was not significantly affected. We also observed some mobilisation of the B cell precursor cells into the mouse spleen, demonstrated with flow cytometry and pre-B colony forming units assays. In summary, the current work demonstrates a severe dysregulation in B lymphocyte development in murine rheumatoid arthritis, with possible implications for B cell repertoire formation, tolerance induction, and disease mechanisms.

Neutrophil-to-lymphocyte ratio an inflammatory biomarker, and prognostic marker in heart failure, cardiovascular disease and chronic inflammatory diseases: New insights for a potential predictor of anti-cytokine therapy responsiveness

In the 20th century, research focused on cholesterol and lipoproteins as the key mechanism in establishing atherosclerotic cardiovascular disease (ASCVD). Given that some studies demonstrated subclinical atherosclerosis in subjects without conventional cardiovascular risk factors, the elevated low-density lipoprotein (LDL) levels alone cannot account for the entire burden of atherosclerosis. Hence, large-scale clinical trials demonstrated the operation of immune and inflammatory pathways in ASCVD. In this regard, the evidence establishes that cells of the immune system, both the innate (neutrophils, macrophages) and adaptive (T cell and other lymphocytes) limbs, contribute to atherosclerosis and atherothrombosis. Besides, basic science studies have identified proatherogenic cytokines such as interleukin (IL)-1, IL-12, and IL-18. In this regard, some studies showed that antiinflammatory therapy targeting the immune system by modulating or blocking interleukins, also known as anti-cytokine therapy, can reduce the risk of major cardiovascular adverse events. The neutrophils play a key role in the innate immune system, representing the acute phase of an inflammatory response. In contrast, lymphocytes represent the adaptive immune system and promote the induction of autoimmune inflammation, especially in the chronic inflammatory response. Through the literature review, we will highlight the inflammatory pathway for the physiopathology of ASCVD, HF, and COVID-19. In this regard, the neutrophil-to-lymphocyte ratio (NLR) integrates the innate immune and adaptive immune systems, making the NLR a biomarker of inflammation. In addition, we provided an update on the evidence showing that high NLR is associated with worse prognosis in heart failure (HF), ASCVD, and COVID-19, as well as their clinical applications showing that the normalization of NLR after anti-cytokine therapy is a potential predictor of therapy responsiveness and is associated with reduction of major adverse cardiovascular events.

Noncanonical B Cells: Characteristics of Uncharacteristic B Cells

B lymphocytes were originally described as a cell type uniquely capable of secreting Abs. The importance of T cell help in Ab production was revealed soon afterward. Following these seminal findings, investigators made great strides in delineating steps in the conventional pathway that B cells follow to produce high-affinity Abs. These studies revealed generalized, or canonical, features of B cells that include their developmental origin and paths to maturation, activation, and differentiation into Ab-producing and memory cells. However, along the way, examples of nonconventional B cell populations with unique origins, age-dependent development, tissue localization, and effector functions have been revealed. In this brief review, features of B-1a, B-1b, marginal zone, regulatory, killer, NK-like, age-associated, and atypical B cells are discussed. Emerging work on these noncanonical B cells and functions, along with the study of their significance for human health and disease, represents an exciting frontier in B cell biology.

FCRL1 immunoregulation in B cell development and malignancy

Immunotherapeutic targeting of surface regulatory proteins and pharmacologic inhibition of critical signaling pathways has dramatically shifted our approach to the care of individuals with B cell malignancies. This evolution in therapy reflects the central role of the B cell receptor (BCR) signaling complex and its co-receptors in the pathogenesis of B lineage leukemias and lymphomas. Members of the Fc receptor-like gene family (FCRL1-6) encode cell surface receptors with complex tyrosine-based regulation that are preferentially expressed by B cells. Among them, FCRL1 expression peaks on naïve and memory B cells and is unique in terms of its intracellular co-activation potential. Recent studies in human and mouse models indicate that FCRL1 contributes to the formation of the BCR signalosome, modulates B cell signaling, and promotes humoral responses. Progress in understanding its regulatory properties, along with evidence for its over-expression by mature B cell leukemias and lymphomas, collectively imply important yet unmet opportunities for FCRL1 in B cell development and transformation. Here we review recent advances in FCRL1 biology and highlight its emerging significance as a promising biomarker and therapeutic target in B cell lymphoproliferative disorders.

Glycome dynamics in T and B cell development: basic immunological mechanisms and clinical applications

Glycans cover the surfaces of all mammalian cells through a process called glycosylation. Nearly all proteins and receptors that integrate the intricate series of co-stimulatory/inhibitory pathways of the immune system are glycosylated. Growing evidence indicates that the development of the immune system at the origins of T and B cell development is tightly regulated by glycosylation. In this opinion, we hypothesize that the glycome composition of developing T and B cells is developmentally regulated. We discuss how glycans play fundamental roles in lymphocyte development and how glycans early define T and B cell functionality in multiple aspects of adaptive immunity. These advances can provide opportunities for the discovery of novel disease factors and more effective candidate treatments for various conditions.

Regulatory roles of cytokines in T and B lymphocytes-mediated immunity in teleost fish

T and B lymphocytes (T and B cells) are immune effector cells that play critical roles in adaptive immunity and defend against external pathogens in most vertebrates, including teleost fish. In mammals, the development and immune response of T and B cells is associated with cytokines including chemokines, interferons, interleukins, lymphokines, and tumor necrosis factors during pathogenic invasion or immunization. Given that teleost fish have evolved a similar adaptive immune system to mammals with T and B cells bearing unique receptors (B-cell receptors (BCRs) and T-cell receptors (TCRs)) and that cytokines in general have been identified, whether the regulatory roles of cytokines in T and B cell-mediated immunity are evolutionarily conserved between mammalians and teleost fish is a fascinating question. Thus, the purpose of this review is to summarize the current knowledge of teleost cytokines and T and B cells as well as the regulatory roles of cytokines on these two types of lymphocytes. This may provide important information on the parallelisms and dissimilarities of the functions of cytokines in bony fish versus higher vertebrates, which may aid in the evaluation and development of adaptive immunity-based vaccines or immunostimulants.

Epigenomic profiling of isolated blood cell types reveals highly specific B cell smoking signatures and links to disease risk

BACKGROUND

Tobacco smoking alters the DNA methylation profiles of immune cells which may underpin some of the pathogenesis of smoking-associated diseases. To link smoking-driven epigenetic effects in specific immune cell types with disease risk, we isolated six leukocyte subtypes, CD14+ monocytes, CD15+ granulocytes, CD19+ B cells, CD4+ T cells, CD8+ T cells, and CD56+ natural killer cells, from whole blood of 67 healthy adult smokers and 74 nonsmokers for epigenome-wide association study (EWAS) using Illumina 450k and EPIC methylation arrays.

RESULTS

Numbers of smoking-associated differentially methylated sites (smCpGs) at genome-wide significance (p < 1.2 × 10-7) varied widely across cell types, from 5 smCpGs in CD8+ T cells to 111 smCpGs in CD19+ B cells. We found unique smoking effects in each cell type, some of which were not apparent in whole blood. Methylation-based deconvolution to estimate B cell subtypes revealed that smokers had 7.2% (p = 0.033) less naïve B cells. Adjusting for naïve and memory B cell proportions in EWAS and RNA-seq allowed the identification of genes enriched for B cell activation-related cytokine signaling pathways, Th1/Th2 responses, and hematopoietic cancers. Integrating with large-scale public datasets, 62 smCpGs were among CpGs associated with health-relevant EWASs. Furthermore, 74 smCpGs had reproducible methylation quantitative trait loci single nucleotide polymorphisms (SNPs) that were in complete linkage disequilibrium with genome-wide association study SNPs, associating with lung function, disease risks, and other traits.

CONCLUSIONS

We observed blood cell-type-specific smCpGs, a naïve-to-memory shift among B cells, and by integrating genome-wide datasets, we identified their potential links to disease risks and health traits.

The physical exercise-induced oxidative/inflammatory response in peripheral blood mononuclear cells: Signaling cellular energetic stress situations

Peripheral blood mononuclear cells (PBMCs) are a variety of specialized immune cells produced in the bone marrow from hematopoietic stem cells (HSCs) that work together to protect our bodies from harmful pathogens. From a metabolic point of view, these cells can serve as sentinel tissue source for distinguishing multiple types of whole-body physiological perturbations. The significant interaction of PBMCs with systemic physiology makes these cells an attractive target for several interventions such as physical exercise. Analyses of oxidative/inflammatory and metabolic markers of PBMCs obtained from unhealthy and healthy humans have been used in monitoring immune response in different exercise conditions. It is already a common consensus that regular practice of physical exercise, that is planned, structured, and repetitive, influences personal health by altering the metabolic state and the immune system. However, the role of distinct metabolic processes responsible for maintaining metabolic balance during physical exercise in PBMCs is not fully understood. Furthermore, a complete dose-response analysis between different exercise protocols and biomarkers capable of predicting physical performance needs to be better elucidated. The absence of published reviews on this topic compromises the understanding of the crosstalk between the metabolic adaptations of PBMCs and exercise-induced changes in the immune system. Given the above, this review highlights the main findings in the literature involving the responses of PBMCs in the inflammatory/oxidative stress induced by physical exercise. The present review also highlights how distinct phenotypes and functional diversity of PBMCs make these cells an accessible alternative for assessing exercise-induced metabolic adaptations.

Cancer-Associated B Cells in Sarcoma

Despite being one of the first types of cancers studied that hinted at a major role of the immune system in pro- and anti-tumor biology, little is known about the immune microenvironment in sarcoma. Few types of sarcoma have shown major responses to immunotherapy, and its rarity and heterogeneity makes it challenging to study. With limited systemic treatment options, further understanding of the underlying mechanisms in sarcoma immunity may prove crucial in advancing sarcoma care. While great strides have been made in the field of immunotherapy over the last few decades, most of these efforts have focused on harnessing the T cell response, with little attention on the role B cells may play in the tumor microenvironment. A growing body of evidence suggests that B cells have both pro- and anti-tumoral effects in a large variety of cancers, and in the age of bioinformatics and multi-omic analysis, the complexity of the humoral response is just being appreciated. This review explores what is currently known about the role of B cells in sarcoma, including understanding the various B cell populations associated with sarcoma, the organization of intra-tumoral B cells in tertiary lymphoid structures, recent trials in immunotherapy in sarcoma, intra-tumoral immunoglobulin, the pro-tumor effects of B cells, and exciting future areas for research.

IgD multiple myeloma: biology, diagnosis, and treatment

IgD multiple myeloma is uncommon. Patients generally present at a younger age and have shorter progression free and overall survivals (OSs). Its rarity has inhibited development of a specific risk stratification system or informed best treatment protocols. We present interphase fluorescence in situ hybridization results from a group of 29 cases. These showed evidence of a decreased male to female ratio, decreased OS in patients aged 70 and over, better outcomes in those with kappa light chain restriction, and CD56 positive patients had longer survivals than those lacking CD56. We discuss the biology of IgD multiple myeloma, the need for prospective studies, and challenges for improvements in diagnosis and treatment. We suggest an International Register to accelerate development of best practice guidelines for diagnosis, risk stratification, and treatment.

Immunoinformatics-guided designing and in silico analysis of epitope-based polyvalent vaccines against multiple strains of human coronavirus (HCoV)

OBJECTIVES

The group of human coronaviruses (HCoVs) consists of some highly pathogenic viruses that have caused several outbreaks in the past. The newly emerged strain of HCoV, the SARS-CoV-2 is responsible for the recent global pandemic that has already caused the death of hundreds of thousands of people due to the lack of effective therapeutic options.

METHODS

In this study, immunoinformatics methods were used to design epitope-based polyvalent vaccines which are expected to be effective against four different pathogenic strains of HCoV i.e., HCoV-OC43, HCoV-SARS, HCoV-MERS, and SARS-CoV-2.

RESULTS

The constructed vaccines consist of highly antigenic, non-allergenic, nontoxic, conserved, and non-homologous T-cell and B-cell epitopes from all the four viral strains. Therefore, they should be able to provide strong protection against all these strains. Protein-protein docking was performed to predict the best vaccine construct. Later, the MD simulation and immune simulation of the best vaccine construct also predicted satisfactory results. Finally, in silico cloning was performed to develop a mass production strategy of the vaccine.

CONCLUSION

If satisfactory results are achieved in further in vivo and in vitro studies, then the vaccines designed in this study might be effective as preventative measures against the selected HCoV strains.

A p38α-BLIMP1 signalling pathway is essential for plasma cell differentiation

Plasma cells (PC) are antibody-secreting cells and terminal effectors in humoral responses. PCs differentiate directly from activated B cells in response to T cell-independent (TI) antigens or from germinal center B (GCB) cells in T cell-dependent (TD) antigen-induced humoral responses, both of which pathways are essentially regulated by the transcription factor BLIMP1. The p38 mitogen-activated protein kinase isoforms have already been implicated in B cell development, but the precise role of p38α in B cell differentiation is still largely unknown. Here we show that PC differentiation and antibody responses are severely impaired in mice with B cell-specific deletion of p38α, while B cell development and the GCB cell response are spared. By utilizing a Blimp1 reporter mouse model, we show that p38α-deficiency results in decreased BLIMP1 expression. p38α-driven BLIMP1 up-regulation is required for both TI and TD PCs differentiation. By combining CRISPR/Cas9 screening and other approaches, we identify TCF3, TCF4 and IRF4 as downstream effectors of p38α to control PC differentiation via Blimp1 transcription. This study thus identifies an important signalling pathway underpinning PC differentiation upstream of BLIMP1, and points to a highly specialized and non-redundant role for p38α among p38 isoforms.

Impact of interaction networks of B cells with other cells on tumorigenesis, progression and response to immunotherapy of renal cell carcinoma: A review

Ample evidence indicates that the development and progression of renal cell carcinoma (RCC) are complex pathological processes involving interactions between tumor cells, immune cells and stromal components. Tumor infiltrated immune cells determine whether tumor advancement is promoted or inhibited. Among them, infiltrated B lymphocytes are present in all stages of RCC, playing a major role in determining tumor formation and advancement, as an essential part in the tumor microenvironment (TME). Although the advent of targeted and immune therapies has remarkably improved the survival of patients with advanced RCC, few cases can achieve complete response due to drug resistance. In this review article, we intend to summary the recent studies that outline the interaction networks of B cells with other cells, discuss the role of B cells in RCC development and progression, and assess their impact on RCC immunotherapy.

Vaccinomics to Design a Multiepitope Vaccine against Legionella pneumophila

Legionella pneumophila is found in the natural aquatic environment and can resist a wide range of environmental conditions. There are around fifty species of Legionella, at least twenty-four of which are directly linked to infections in humans. L. pneumophila is the cause of Legionnaires' disease, a potentially lethal form of pneumonia. By blocking phagosome-lysosome fusion, L. pneumophila lives and proliferates inside macrophages. For this disease, there is presently no authorized multiepitope vaccine available. For the multi-epitope-based vaccine (MEBV), the best antigenic candidates were identified using immunoinformatics and subtractive proteomic techniques. Several immunoinformatics methods were utilized to predict B and T cell epitopes from vaccine candidate proteins. To construct an in silico vaccine, epitopes (07 CTL, 03 HTL, and 07 LBL) were carefully selected and docked with MHC molecules (MHC-I and MHC-II) and human TLR4 molecules. To increase the immunological response, the vaccine was combined with a 50S ribosomal adjuvant. To maximize vaccine protein expression, MEBV was cloned and reverse-translated in Escherichia coli. To prove the MEBV's efficacy, more experimental validation is required. After its development, the resulting vaccine is greatly hoped to aid in the prevention of L. pneumophila infections.

Conserved Role of mTORC1 Signaling in B Cell Immunity in Teleost Fish

Mammalian studies have demonstrated that B cell immune responses are regulated by mechanistic target of rapamycin complex 1 (mTORC1) signaling. Teleost fish represent the oldest living bony vertebrates that contain bona fide B cells. So far, whether the regulatory mechanism of mTORC1 signaling in B cells occurred in teleost fish is still unknown. In this study, we developed a fish model by using rapamycin (RAPA) treatment to inhibit mTORC1 signaling and demonstrated the role of mTORC1 signaling in teleost B cells. In support, we found inhibition of mTORC1 signaling by RAPA decreased the phagocytic capacity, proliferation, and Ig production of B cells. Critically, Flavobacterium columnare induced specific IgM binding in serum, and these titers were significantly inhibited by RAPA treatment, thus decreasing Ab-mediated agglutination of F. columnare and significantly increasing the susceptibility of fish upon F. columnare reinfection. Collectively, our findings elucidated that the mTORC1 pathway is evolutionarily conserved in regulating B cell responses, thus providing a new point for understanding the B cells functions in teleost fish.

Allelic polymorphism controls autoreactivity and vaccine elicitation of human broadly neutralizing antibodies against influenza virus

Human broadly neutralizing antibodies (bnAbs) targeting the hemagglutinin stalk of group 1 influenza A viruses (IAVs) are biased for IGHV1-69 alleles that use phenylalanine (F54) but not leucine (L54) within their CDRH2 loops. Despite this, we demonstrated that both alleles encode for human IAV bnAbs that employ structurally convergent modes of contact to the same epitope. To resolve differences in lineage expandability, we compared F54 versus L54 as substrate within humanized mice, where antibodies develop with human-like CDRH3 diversity but are restricted to single VH genes. While both alleles encoded for bnAb precursors, only F54 IGHV1-69 supported elicitation of heterosubtypic serum bnAbs following immunization with a stalk-only nanoparticle vaccine. L54 IGHV1-69 was unproductive, co-encoding for anergic B cells and autoreactive stalk antibodies that were cleared from B cell memory. Moreover, human stalk antibodies also demonstrated L54-dependent autoreactivity. Therefore, IGHV1-69 polymorphism, which is skewed ethnically, gates tolerance and vaccine expandability of influenza bnAbs.

A SLC35C2 Transporter-Targeting Fluorescent Probe for the Selective Detection of B Lymphocytes Identified by SLC-CRISPRi and Unbiased Fluorescence Library Screening

T and B lymphocytes are two major adaptive immune cells in the human defense system. To real-time monitor their diverse functions, a live-cell-selective probe for only one cell type is need to investigate the complex interaction of the immune cells. Herein, a small-molecule probe CDyB for live B cells is developed by an unbiased fluorescence library screening. The cell selectivity was confirmed by multiparametric single-cell analysis using CyTOF. Through a systematic SLC-CRISPRi library screening, the molecular target of CDyB was identified as SLC35C2 transporter based on a gating-oriented live-cell distinction (GOLD) mechanism. The gene expression analysis and knock-out experiments validated that the SLC35C2 transporter was the target for CDyB distinction. Interestingly, when CDyB was applied to study B cell development, the CDyB fluorescence and SLC35C2 expression were positively correlated with the B cell maturation process, and not involved in the T cell development.

Deletion of Mettl3 at the Pro-B Stage Marginally Affects B Cell Development and Profibrogenic Activity of B Cells in Liver Fibrosis

N6-methyladenosine (m⁶A) modification plays a pivotal role in cell fate determination. Previous studies show that eliminating m⁶A using Mb1-Cre dramatically impairs B cell development. However, whether disturbing m⁶A modification at later stages affects B cell development and function remains elusive. Here, we deleted m⁶A methyltransferase Mettl3 from the pro-B stage on using Cd19-Cre (Mettl3 cKO) and found that the frequency of total B cells in peripheral blood, peritoneal cavity, and liver is comparable between Mettl3 cKO mice and wild-type (WT) littermates, while the percentage of whole splenic B cells slightly increases in Mettl3 cKO individuals. The proportion of pre-pro-B, pro-B, pre-B, immature, and mature B cells in the bone marrow were minimally affected. Loss of Mettl3 resulted in increased apoptosis but barely affected B cells' proliferation and IgG production upon LPS, CD40L, anti-IgM, or TNF-α stimulation. Different stimuli had different effects on B cell activation. In addition, B cell-specific Mettl3 knockout had no influence on the pro-fibrogenic activity of B cells in liver fibrosis, evidenced by comparable fibrosis in carbon tetrachloride- (CCl₄-) treated Mettl3 cKO mice and WT controls. In summary, our study demonstrated that deletion of Mettl3 from the pro-B stage on has minimal effects on B cell development and function, as well as profibrogenic activity of B cells in liver fibrosis, revealing a stage-specific dependence on Mettl3-mediated m⁶A of B cell development.

Modulation of Peripheral Immune Cell Subpopulations After RapidArc/Moderate Hypofractionated Radiotherapy for Localized Prostate Cancer: Findings and Comparison With 3D Conformal/Conventional Fractionation Treatment

Radiotherapy (RT) is an important therapeutic option in patients with localized prostate cancer (PC). Unfortunately, radiation treatment causes a decrease in peripheral lymphocytes and, consequently, influences the patients' immune status. Our aim was to study changes in peripheral blood immune cell subpopulations after RT and during 6 months' follow-up in 2 groups of PC patients irradiated with different techniques and dose fractions with curative intent. We also investigated the presence of correlation between immune cell modulation and genitourinary or gastrointestinal toxicity. We enrolled 44 patients treated with curative RT (RapidArc/hypofractionation regimen or 3D conformal/conventional fractionation) for localized PC. Total white blood cell (WBC), absolute lymphocyte counts (ALCs), and peripheral immune cell subpopulations were analyzed at baseline, at the end of RT, and 3 and 6 months after the end of RT. WBC and ALC greatly decreased at the end of RT with a trend to recover at 6 months' follow-up in the hypofractionation group but not in the conventional one. Furthermore, B, total T, T CD4+, T CD8+, and NK cell values dropped significantly in both groups at the end of RT, with a minor decrease detectable in the hypofractionation group for B, total T, and T CD4+ lymphocytes with respect to the other technique/fractionation group. Double-negative T (DNT), double-positive T (DPT), and NKT cells significantly decreased at the end of RT with a slight tendency to recover values during follow-up, particularly in the hypofractionation group. No correlation with genitourinary or gastrointestinal toxicity was found. In this study, we showed, for the first time, the effects of RapidArc/moderate hypofractionation RT on immune cell subsets in patients treated for localized PC. Due to the growing interest in minority T-cell subpopulations for immunotherapy, we also reported longitudinal monitoring of the effects of RT on DNT, DPT, and NKT, which was never studied before. Our preliminary data highlight the importance of considering the effects of different RT techniques/fractionation regimens on peripheral immune cells, in the era of RT and immunotherapy combination.

B cells in autoimmune hepatitis: bystanders or central players?

B cells are central for the adaptive immune system to mount successful immune responses not only as antibody producers but also as regulators of cellular immunity. These multifaceted features are also reflected in autoimmunity where autoreactive B cells can fuel disease by production of cytotoxic autoantibodies, presentation of autoantigens to autoreactive T cells, and secretion of cytokines and chemokines that either promote detrimental immune activation or impair regulatory T and B cells. The role of B cells and autoantibodies in autoimmune hepatitis (AIH) have been controversially discussed, with typical autoantibodies and hypergammaglobulinemia indicating a key role, while strong HLA class II association suggests T cells as key players. In this review, we summarize current knowledge on B cells in AIH and how different B cell subpopulations may drive AIH progression beyond autoantibodies. We also discuss recent findings of B cell-directed therapies in AIH.

Uniting Disciplines to Develop Therapeutics: Targeted mRNA Lipid Nanoparticles Reprogram the Immune System In Vivo to Treat Heart Disease

The burgeoning field of immunomedicine is primed to expand beyond oncology (Aghajanian et al., 2022). Over the past several decades, many cell-based therapies have been proposed, developed, and deployed in the clinic. The recent explosion of targeted cell therapies has primarily been aimed at oncological malignancies. In parallel, cardiology researchers have been investigating the various cell types that contribute to heart diseases, especially those responsible for tissue fibrosis and myocardial dysfunction. Our laboratory proposed in 2019 to unite these two disciplines: could a targeted cell therapy be used to ameliorate cardiac fibrosis (Aghajanian et al., 2019). Although preliminary results were encouraging, the genetic engineering approach used to manufacture immune cells would result in persistent cytolytic T cell if directly translated to humans. This would pose a safety concern since activated fibroblasts are essential cells in the setting of acute injury. Therefore, we developed a novel technology to deliver modified RNA to T cells in vivo, resulting in a transient antiactivated fibroblast therapeutic (Rurik et al., 2022). Although active for only a few days, these cells were sufficient to significantly improve cardiac function in a murine model of cardiac fibrosis. These results pave the way for low-cost and scalable, and dose-able and immune therapy for fibrotic disorders.

Whole-Transcriptome Profiling and circRNA-miRNA-mRNA Regulatory Networks in B-Cell Development

The generation and differentiation of B lymphocytes (B cells) is a flexible process with many critical regulatory factors. Previous studies indicated that non-coding RNAs play multiple roles in the development of lymphocytes. However, little has been known about the circular RNA (circRNA) profiles and their competing endogenous RNA (ceRNA) networks in B-cell development and differentiation. Here, four B-cell subsets were purified from single-cell suspensions of mouse bone marrow. Then RNA sequencing (RNA-Seq) was used to display expression profiles of circRNAs, miRNAs and mRNAs during B-cell differentiation. 175, 203, 219 and 207 circRNAs were specifically expressed in pro-B cells, pre-B cells, immature B cells and mature B cells, respectively. The circRNA-associated ceRNA networks constructed in two sequential stages of B-cell differentiation revealed the potential mechanism of circRNAs in these processes. This study is the first to explore circRNA profiles and circRNA-miRNA-mRNA networks in different B-cell developmental stages of mouse bone marrow, which contribute to further research on their mechanism in B-cell development and differentiation.

miR-582 negatively regulates pre-B cell proliferation and survival through targeting Hif1α and Rictor

B cell development in bone marrow (BM) is a multi-staged process involving pro-B, pre-B, immature B, and mature B cells, among which pre-B cells undergo vigorous proliferation, differentiation, apoptosis, and gene rearrangement. While several signaling pathways participate in pre-B cell development have been clarified, detailed intrinsic mechanisms regulating pre-B cell proliferation and survival have not been fully understood. In the current study, we report that miR-582 regulates pre-B cell proliferation and survival. miR-582 is enriched in pre-B cells. Deletion of miR-582 in mice expanded the BM pre-B cell population in a cell-autonomous manner as shown by competitive BM transplantation. We show that forced miR-582 overexpression inhibited pre-B cell proliferation and survival, whereas downregulation of miR-582 by siRNA significantly promoted pre-B cell proliferation and survival in vitro. We identified that Hif1α and Rictor are authentic targets of miR-582 in pre-B cells as shown by reporter assays. Moreover, miR-582 overexpression reduced the expression of Hif1α and its downstream molecule Glut1, as well as Rictor and mTORC2 activity as shown by attenuated AKT and FoxO1 phosphorylation, while miR-582 knockdown showed opposite effects. miR-582 knockdown-induced increases in pre-B proliferation and survival was abrogated by Hif1α and Rictor inhibitors. Together, miR-582 functions as a negative regulator of pre-B cell proliferation and survival by simultaneously targeting Hif1α and mTORC2 signaling that regulates metabolism in early B cell development.

Towards Tabula Gallus

The Tabula Gallus is a proposed project that aims to create a map of every cell type in the chicken body and chick embryos. Chickens (Gallus gallus) are one of the most recognized model animals that recapitulate the development and physiology of mammals. The Tabula Gallus will generate a compendium of single-cell transcriptome data from Gallus gallus, characterize each cell type, and provide tools for the study of the biology of this species, similar to other ongoing cell atlas projects (Tabula Muris and Tabula Sapiens/Human Cell Atlas for mice and humans, respectively). The Tabula Gallus will potentially become an international collaboration between many researchers. This project will be useful for the basic scientific study of Gallus gallus and other birds (e.g., cell biology, molecular biology, developmental biology, neuroscience, physiology, oncology, virology, behavior, ecology, and evolution). It will eventually be beneficial for a better understanding of human health and diseases.

Graphene oxide activates B cells with upregulation of granzyme B expression: evidence at the single-cell level for its immune-modulatory properties and anticancer activity

We recently found by single-cell mass cytometry that ex vivo human B cells internalize graphene oxide (GO). The functional impact of such uptake on B cells remains unexplored. Here, we disclosed the effects of GO and amino-functionalized GO (GONH₂) interacting with human B cells in vitro and ex vivo at the protein and gene expression levels. Moreover, our study considered three different subpopulations of B cells and their functionality in terms of: (i) cytokine production, (ii) activation markers, (iii) killing activity towards cancer cells. Single-cell mass cytometry screening revealed the higher impact of GO on cell viability towards naïve, memory, and plasma B cell subsets. Different cytokines such as granzyme B (GrB) and activation markers, like CD69, CD80, CD138, and CD38, were differently regulated by GONH₂ compared to GO, supporting possible diverse B cell activation paths. Moreover, co-culture experiments also suggest the functional ability of both GOs to activate B cells and therefore enhance the toxicity towards HeLa cancer cell line. Complete transcriptomic analysis on a B cell line highlighted the distinctive GO and GONH₂ elicited responses, inducing pathways such as B cell receptor and CD40 signaling pathways, key players for GrB secretion. B cells were regularly left behind the scenes in graphene biological studies; our results may open new horizons in the development of GO-based immune-modulatory strategies having B cell as main actors.

Nanomedicines in B cell-targeting therapies

B cells play multiple roles in immune responses related to autoimmune diseases as well as different types of cancers. As such, strategies focused on B cell targeting attracted wide interest and developed intensively. There are several common mechanisms various B cell targeting therapies have relied on, including direct B cell depletion, modulation of B cell antigen receptor (BCR) signaling, targeting B cell survival factors, targeting the B cell and T cell costimulation, and immune checkpoint blockade. Nanocarriers, used as drug delivery vehicles, possess numerous advantages to low molecular weight drugs, reducing drug toxicity, enhancing blood circulation time, as well as augmenting targeting efficacy and improving therapeutic effect. Herein, we review the commonly used targets involved in B cell targeting approaches and the utilization of various nanocarriers as B cell-targeted delivery vehicles. STATEMENT OF SIGNIFICANCE: As B cells are engaged significantly in the development of many kinds of diseases, utilization of nanomedicines in B cell depletion therapies have been rapidly developed. Although numerous studies focused on B cell targeting have already been done, there are still various potential receptors awaiting further investigation. This review summarizes the most relevant studies that utilized nanotechnologies associated with different B cell depletion approaches, providing a useful tool for selection of receptors, agents and/or nanocarriers matching specific diseases. Along with uncovering new targets in the function map of B cells, there will be a growing number of candidates that can benefit from nanoscale drug delivery.

Development of a Candidate Multi-Epitope Subunit Vaccine against Klebsiella aerogenes: Subtractive Proteomics and Immuno-Informatics Approach

Klebsiella aerogenes is a Gram-negative bacterium which has gained considerable importance in recent years. It is involved in 10% of nosocomial and community-acquired urinary tract infections and 12% of hospital-acquired pneumonia. This organism has an intrinsic ability to produce inducible chromosomal AmpC beta-lactamases, which confer high resistance. The drug resistance in K. aerogenes has been reported in China, Israel, Poland, Italy and the United States, with a high mortality rate (~50%). This study aims to combine immunological approaches with molecular docking approaches for three highly antigenic proteins to design vaccines against K. aerogenes. The synthesis of the B-cell, T-cell (CTL and HTL) and IFN-γ epitopes of the targeted proteins was performed and most conserved epitopes were chosen for future research studies. The vaccine was predicted by connecting the respective epitopes, i.e., B cells, CTL and HTL with KK, AAY and GPGPG linkers and all these were connected with N-terminal adjuvants with EAAAK linker. The humoral response of the constructed vaccine was measured through IFN-γ and B-cell epitopes. Before being used as vaccine candidate, all identified B-cell, HTL and CTL epitopes were tested for antigenicity, allergenicity and toxicity to check the safety profiles of our vaccine. To find out the compatibility of constructed vaccine with receptors, MHC-I, followed by MHC-II and TLR4 receptors, was docked with the vaccine. Lastly, in order to precisely certify the proper expression and integrity of our construct, in silico cloning was carried out. Further studies are needed to confirm the safety features and immunogenicity of the vaccine.

Proteome-Wide Mapping and Reverse Vaccinology Approaches to Design a Multi-Epitope Vaccine against Clostridium perfringens

C. perfringens is a highly versatile bacteria of livestock and humans, causing enteritis (a common food-borne illness in humans), enterotoxaemia (in which toxins are formed in the intestine which damage and destroy organs, i.e., the brain), and gangrene (wound infection). There is no particular cure for the toxins of C. perfringens. Supportive care (medical control of pain, intravenous fluids) is the standard treatment. Therefore, a multiple-epitope vaccine (MEV) should be designed to battle against C. perfringens infection. Furthermore, the main objective of this in silico investigation is to design an MEV that targets C. perfringens. For this purpose, we selected the top three proteins that were highly antigenic using immuno-informatics approaches, including molecular docking. B-cells, IFN-gamma, and T cells for target proteins were predicted and the most conserved epitopes were selected for further investigation. For the development of the final MEV, epitopes of LBL5, CTL17, and HTL13 were linked to GPGPG, AAY, and KK linkers. The vaccine N-end was joined to an adjuvant through an EAAK linker to improve immunogenicity. After the attachment of linkers and adjuvants, the final construct was 415 amino acids. B-cell and IFN-gamma epitopes demonstrate that the model structure is enhanced for humoral and cellular immune responses. To validate the immunogenicity and safety of the final construct, various physicochemical properties, and other properties such as antigenicity and non-allergens, were evaluated. Furthermore, molecular docking was carried out for verification of vaccine compatibility with the receptor, evaluated in silico. Also, in silico cloning was employed for the verification of the proper expression and credibility of the construct.

Development of a Conserved Chimeric Vaccine for Induction of Strong Immune Response against Staphylococcus aureus Using Immunoinformatics Approaches

Staphylococcus aureus is one of the most notorious Gram-positive bacteria with a very high mortality rate. The WHO has listed S. aureus as one of the ESKAPE pathogens requiring urgent research and development efforts to fight against it. Yet there is a major layback in the advancement of effective vaccines against this multidrug-resistant pathogen. SdrD and SdrE proteins are attractive immunogen candidates as they are conserved among all the strains and contribute specifically to bacterial adherence to the host cells. Furthermore, these proteins are predicted to be highly antigenic and essential for pathogen survival. Therefore, in this study, using the immunoinformatics approach, a novel vaccine candidate was constructed using highly immunogenic conserved T-cell and B-cell epitopes along with specific linkers, adjuvants, and consequently modeled for docking with human Toll-like receptor 2. Additionally, physicochemical properties, secondary structure, disulphide engineering, and population coverage analysis were also analyzed for the vaccine. The constructed vaccine showed good results of worldwide population coverage and a promising immune response. For evaluation of the stability of the vaccine-TLR-2 docked complex, a molecular dynamics simulation was performed. The constructed vaccine was subjected to in silico immune simulations by C-ImmSim and Immune simulation significantly provided high levels of immunoglobulins, T-helper cells, T-cytotoxic cells, and INF-γ. Lastly, upon cloning, the vaccine protein was reverse transcribed into a DNA sequence and cloned into a pET28a (+) vector to ensure translational potency and microbial expression. The overall results of the study showed that the designed novel chimeric vaccine can simultaneously elicit humoral and cell-mediated immune responses and is a reliable construct for subsequent in vivo and in vitro studies against the pathogen.

Impaired memory B-cell recall responses in the elderly following recurrent influenza vaccination

Influenza is a highly contagious viral respiratory disease that affects million of people worldwide each year. Annual vaccination is recommended by the World Health Organization with the goal of reducing influenza severity and limiting transmission through elicitation of antibodies targeting the hemagglutinin (HA) glycoprotein. The antibody response elicited by current seasonal influenza virus vaccines is predominantly strain-specific, but pre-existing influenza virus immunity can greatly impact the serological antibody response to vaccination. However, it remains unclear how B cell memory is shaped by recurrent annual vaccination over the course of multiple seasons, especially in high-risk elderly populations. Here, we systematically profiled the B cell response in young adult (18-34 year old) and elderly (65+ year old) vaccine recipients that received annual split inactivated influenza virus vaccination for 3 consecutive seasons. Specifically, the antibody serological and memory B-cell compartments were profiled for reactivity against current and historical influenza A virus strains. Moreover, multiparametric analysis and antibody landscape profiling revealed a transient increase in strain-specific antibodies in the elderly, but with an impaired recall response of pre-existing memory B-cells, plasmablast (PB) differentiation and long-lasting serological changes. This study thoroughly profiles and compares the immune response to recurrent influenza virus vaccination in young and elderly participants unveiling the pitfalls of current influenza virus vaccines in high-risk populations.

Critical roles of the E3 ubiquitin ligase FBW7 in B-cell response and the pathogenesis of experimental autoimmune arthritis

Proper regulation of B-cell function is essential for effective humoral immunity and maintenance of immune tolerance. Here, we found that FBW7 (F-box/WD40 repeat-containing protein 7) is highly expressed in germinal centre B and B1 cells, and confirmed that it has an intrinsic role in maintaining homeostasis of mature B cells and B-1 cells. FBW7 deletion led to an impairment of antibody response, and although germinal centre formation was not affected, antibody class-switch recombination and affinity maturation processes were defective. Likewise, memory immune response was severely impaired. Moreover, FBW7 ablation ameliorated the pathogenesis of an autoimmune disease model, collagen-induced arthritis, by reducing the production of anti-collagen II autoantibodies. Taken together, these data suggest that FBW7 may be an attractive target for developing new therapeutics for the treatment of autoimmune diseases.

Know your enemy or find your friend?-Induction of IgA at mucosal surfaces

Most antibodies produced in the body are of the IgA class. The dominant cell population producing them are plasma cells within the lamina propria of the gastrointestinal tract, but many IgA-producing cells are also found in the airways, within mammary tissues, the urogenital tract and inside the bone marrow. Most IgA antibodies are transported into the lumen by epithelial cells as part of the mucosal secretions, but they are also present in serum and other body fluids. A large part of the commensal microbiota in the gut is covered with IgA antibodies, and it has been demonstrated that this plays a role in maintaining a healthy balance between the host and the bacteria. However, IgA antibodies also play important roles in neutralizing pathogens in the gastrointestinal tract and the upper airways. The distinction between the two roles of IgA - protective and balance-maintaining - not only has implications on function but also on how the production is regulated. Here, we discuss these issues with a special focus on gut and airways.

Mechanisms for the regulation of memory B-cell recall responses in mice

Upon infection by pathogens or vaccination, the adaptive immune system rapidly but transiently produces antibodies. Some weeks later, however, long-lasting immunity is established that protects the host against the same pathogens almost for life through continuous production of antibodies on one hand and the maintenance of cytotoxic T cells on the other, collectively called immunological memory. The antibody-mediated arm, also called serological memory, is mainly exerted by long-lived plasma cells and memory B cells (MBCs). MBCs express receptors for the specific pathogens and circulate to survey the body for almost a life-long period. Upon recognizing the pathogen, MBCs clonally expand and produce a large amount of the specific antibodies to stop the infection, the process called a (memory) recall response. Although such a function of MBCs has long been known, the mechanism of how their performance is regulated has been obscure. This is due to their paucity in the body, lack of definitive surface markers and obscure ontogeny. However, recent studies have revealed the multifold mechanisms by which the recall response of MBCs is regulated: Rapid and enhanced antibody production is due to a mechanism intrinsic to MBCs; namely, upregulated expression levels of surface molecules interacting with T cells and the property of IgG-class antigen receptors; to a property of the responsible subset of MBCs; and to co-stimulation through innate receptors and cytokines. It has also been unveiled that the recall response is negatively regulated by an inhibitory receptor on MBCs and by antigens with repetitive epitopes.

B Cells in Atherosclerosis: Mechanisms and Potential Clinical Applications

•

B cells regulate atherosclerotic plaque formation through production of antibodies and cytokines, and effects are subset specific (B1 and B2).

•

Putative human atheroprotective B1 cells function similarly to murine B1 in their spontaneous IgM antibody production. However, marker strategies in identifying human and murine B1 are different.

•

IgM antibody to oxidation specific epitopes produced by B1 cells associate with human coronary artery disease.

•

Neoantigen immunization may be a promising strategy for atherosclerosis vaccine development, but further study to determine relevant antigens still need to be done.

•

B-cell–targeted therapies, used in treating autoimmune diseases as well as lymphoid cancers, might have potential applications in treating cardiovascular diseases. Short- and long-term cardiovascular effects of these agents need to be assessed.

Because atherosclerotic cardiovascular disease is a leading cause of death worldwide, understanding inflammatory processes underpinning its pathology is critical. B cells have been implicated as a key immune cell type in regulating atherosclerosis. B-cell effects, mediated by antibodies and cytokines, are subset specific. In this review, we focus on elaborating mechanisms underlying subtype-specific roles of B cells in atherosclerosis and discuss available human data implicating B cells in atherosclerosis. We further discuss potential B cell–linked therapeutic approaches, including immunization and B cell–targeted biologics. Given recent evidence strongly supporting a role for B cells in human atherosclerosis and the expansion of immunomodulatory agents that affect B-cell biology in clinical use and clinical trials for other disorders, it is important that the cardiovascular field be cognizant of potential beneficial or untoward effects of modulating B-cell activity on atherosclerosis.

Integrated Core Proteomics, Subtractive Proteomics, and Immunoinformatics Investigation to Unveil a Potential Multi-Epitope Vaccine against Schistosomiasis

Schistosomiasis is a parasitic infection that causes considerable morbidity and mortality in the world. Infections of parasitic blood flukes, known as schistosomes, cause the disease. No vaccine is available yet and thus there is a need to design an effective vaccine against schistosomiasis. Schistosoma japonicum, Schistosoma mansoni, and Schistosoma haematobium are the main pathogenic species that infect humans. In this research, core proteomics was combined with a subtractive proteomics pipeline to identify suitable antigenic proteins for the construction of a multi-epitope vaccine (MEV) against human-infecting Schistosoma species. The pipeline revealed two antigenic proteins-calcium binding and mycosubtilin synthase subunit C-as promising vaccine targets. T and B cell epitopes from the targeted proteins were predicted using multiple bioinformatics and immunoinformatics databases. Seven cytotoxic T cell lymphocytes (CTL), three helper T cell lymphocytes (HTL), and four linear B cell lymphocytes (LBL) epitopes were fused with a suitable adjuvant and linkers to design a 217 amino-acid-long MEV. The vaccine was coupled with a TLR-4 agonist (RS-09; Sequence: APPHALS) adjuvant to enhance the immune responses. The designed MEV was stable, highly antigenic, and non-allergenic to human use. Molecular docking, molecular dynamics (MD) simulations, and molecular mechanics/generalized Born surface area (MMGBSA) analysis were performed to study the binding affinity and molecular interactions of the MEV with human immune receptors (TLR2 and TLR4) and MHC molecules (MHC I and MHC II). The MEV expression capability was tested in an Escherichia coli (strain-K12) plasmid vector pET-28a(+). Findings of these computer assays proved the MEV as highly promising in establishing protective immunity against the pathogens; nevertheless, additional validation by in vivo and in vitro experiments is required to discuss its real immune-protective efficacy.

B cells modulate the expression of MHC-II on cardiac CCR2- macrophages

The uninjured murine heart contains a heterogeneous population of macrophages with disparate ontogenies and functions. These macrophages are often associated with blood vessels and can be subclassified based on the expression of CC chemokine receptor 2 (CCR2) and major histocompatibility complex class II (MHC-II). The biological cues that modulate these macrophage pool subpopulations have not been completely identified. It has been recently shown that a sub-population of circulating naïve B cells adheres to the myocardial microvasculature. We hypothesized that B cells might modulate the phenotype of myocardial macrophages. To test this hypothesis, we analyzed both the relative location of B cells and macrophages in myocardial histological section and the prevalence of myocardial macrophage subsets in hearts from B cell-deficient mice (μMT) and mice depleted of B cells through administration of an anti-CD20 antibody. We found that B cells pause in the microvasculature in proximity of macrophages and modulate the number of myocardial CCR2^-MHC-II^high cells. Through in vitro studies we found that this is likely the result of a paracrine effect of B cells on the expression of MHC-II in CCR2^- cells. These results reveal an unexpected relationship between B cells and resident macrophages and, highlighting a direct intramyocardial effect of circulating B cells, challenge the currently held belief that naïve recirculating B lymphocytes merely shuttle between lymphoid stations.

Evidence-Based Immunotherapeutic Effects of Herbal Compounds on Humoral Immunity: Ancient and New Approaches

The human immune system represents a dynamic multiscale system with high complexity in biology. Humoral immunity, as the main branch of adaptive immunity, is characterized by differentiated stages of the B lymphocytes, producing the final product of antibodies that has a diversity of the tuning mechanisms within genetic and epigenetic levels in confrontation with environmental exposures. Disorders because of disturbed humoral immunity are linked with dysregulation of feedback-regulated signaling and the dynamic of immune components that determine the overall response. Food products, mainly herbal components have a significant role in tailoring the immune system micro-ecosystem which can diversify the adaptive nature of humoral immunity. Herein, we review the current evidence-based approaches for the impact of medicinal herbs on humoral immunity signaling and antibody production with a focus on immunotherapeutic applications.

Immune System Alterations in Multiple Myeloma: Molecular Mechanisms and Therapeutic Strategies to Reverse Immunosuppression

Simple Summary

A common characteristic of multiple myeloma (MM) is the dysfunction of patients’ immune system, a condition termed immunosuppression. This state is mainly due to alterations in the number and functionality of the principal immune populations. In this setting, immunotherapy has acquired high relevance in the last years and the investigation of agents that boost the immune system represent a field of interest. In the present review, we will summarize the main cellular and molecular alterations observed in MM patients’ immune system. Furthermore, we will describe the mechanisms of action of the four immunotherapeutic drugs approved so far for the treatment of MM, which are part of the group of monoclonal antibodies (mAbs). Finally, the immune-stimulating effects of several therapeutic agents are described due to their potential role in reversing immunosuppression and, therefore, in favoring the efficacy of immunotherapy drugs, such as mAbs, as part of future pharmacological combinations.

Abstract

Immunosuppression is a common feature of multiple myeloma (MM) patients and has been associated with disease evolution from its precursor stages. MM cells promote immunosuppressive effects due to both the secretion of soluble factors, which inhibit the function of immune effector cells, and the recruitment of immunosuppressive populations. Alterations in the expression of surface molecules are also responsible for immunosuppression. In this scenario, immunotherapy, as is the case of immunotherapeutic monoclonal antibodies (mAbs), aims to boost the immune system against tumor cells. In fact, mAbs exert part of their cytotoxic effects through different cellular and soluble immune components and, therefore, patients’ immunosuppressive status could reduce their efficacy. Here, we will expose the alterations observed in symptomatic MM, as compared to its precursor stages and healthy subjects, in the main immune populations, especially the inhibition of effector cells and the activation of immunosuppressive populations. Additionally, we will revise the mechanisms responsible for all these alterations, including the interplay between MM cells and immune cells and the interactions among immune cells themselves. We will also summarize the main mechanisms of action of the four mAbs approved so far for the treatment of MM. Finally, we will discuss the potential immune-stimulating effects of non-immunotherapeutic drugs, which could enhance the efficacy of immunotherapeutic treatments.

Rational design of multimeric based subunit vaccine against Mycoplasma pneumonia: Subtractive proteomics with immunoinformatics framework

Mycoplasma pneumoniae is the prevalent cause of acquired respiratory infections around the globe. A multi-epitope vaccine (MEV) must be developed to combat infections of M. pneumoniae because there is no specific disease-modifying treatment or vaccination is present. The objective of this research is to design a vaccine that targets M. pneumoniae top five highly antigenic proteins using a combination of immunological techniques and molecular docking. T-cell (HTL & CTL), B-cell, and IFN-γ of target proteins were forecasted and highly conservative epitopes were chosen for further study. For designing of final vaccine, 4LBL, 7CTL, and 5HTL epitopes were joined by linkers of KK, AAY, and GPGPG. The N-end of the vaccine was linked to an adjuvant (Cholera enterotoxin subunit B) with a linker named EAAAK to enhance immunogenicity. After the addition of adjuvants and linkers, the size of the construct was 395 amino acids. The epitopes of IFN-γ and B-cells illustrate that the model construct is optimized for cell-mediated immune or humoral responses. To ensure that the final design is safer and immunogenic, properties like non-allergens, antigenicity, and various physicochemical properties were evaluated. Molecular docking of the vaccine with the toll-like receptor 4 (TLR4) was conducted to check the compatibility of the vaccine with the receptor. Besides, in-silico cloning was utilized for validation of the credibility and proper expression of the vaccine. Furthermore, to confirm that the multi-epitope vaccine created is protective and immunogenic, this research requires experimental validation.