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Background Brucellosis, as a serious zoonotic infectious disease, has been recognized as a re-emerging disease in the developing countries worldwide. In china, the incidence of brucellosis is increasing each year, seriously threatening the health of humans as well as animal populations. Despite a quite number of diagnostic methods currently being used for brucellosis, innovative technologies are still needed for its rapid and accurate diagnosis, especially in area where traditional diagnostic is unavailable. Methodology/Principal findings In this study, a total of 22 B cell linear epitopes were predicted from five Brucella outer membrane proteins (OMPs) using an immunoinformatic approach. These epitopes were then chemically synthesized, and with the method of indirect ELISA (iELISA), each of them displayed a certain degree of capability in identifying human brucellosis positive sera. Subsequently, a fusion protein consisting of the 22 predicted epitopes was prokaryotically expressed and used as diagnostic antigen in a newly established brucellosis testing method, nano-ZnO modified paper-based ELISA (nano-p-ELISA). According to the verifying test using a collection of sera collected from brucellosis and non-brucellosis patients, the sensitivity and specificity of multiepitope based nano-p-ELISA were 92.38% and 98.35% respectively. The positive predictive value was 98.26% and the negative predictive value was 91.67%. The multiepitope based fusion protein also displayed significantly higher specificity than Brucella lipopolysaccharide (LPS) antigen. Conclusions B cell epitopes are important candidates for serologically testing brucellosis. Multiepitope fusion protein based nano-p-ELISA displayed significantly sensitivity and specificity compared to Brucella LPS antigen. The strategy applied in this study will be helpful to develop rapid and accurate diagnostic method for brucellosis in human as well as animal populations., Author summary Brucellosis is one of the most important zoonosis in the world and has caused tremendous economic losses in agriculture and animal husbandry in many countries. Developing rapid, sensitive and specific diagnostic methods is very important for early detection and treatment of brucellosis patients. In this study, a novel diagnostic technique, nano-ZnO modified paper ELISA, was established. The antigen used in this technique was a fusion protein containing multiple B cell epitopes, which were predicted from Brucella major outer membrane proteins such as Bp26, Omp31, Omp16, Omp2b and Omp25. Comparing to traditional LPS antigen, this multiepitope based antigen displayed considerably higher sensitivity and higher specificity in laboratory. With the strategy described in this paper, more efficient epitopes and protein antigen can be identified in the future. Currently, LPS antigen is only prepared from live Brucella, while protein antigen can be produced in large quantities in prokaryotic expression system. In addition to nano-p-ELISA, this protein antigen can also be used for development other methods such as fluorescent polarization assay (FPA) and immunochromatographic assay (ICA) to meet the varied demand for brucellosis testing.

Several B-cell subsets with distinct functions and polarized cytokine profiles that extend beyond antibody production have been reported in different cancers. Here we have demonstrated that proliferating B cells were predominantly found in the peritumoral region of esophageal squamous cell carcinoma (ESCC). These B cells were enriched in tumor nests with high expression of high-mobility group box 1 (HMGB1). High densities of peritumoral proliferating B cells and concomitantly high intratumoral HMGB1 expression showed improved prognostic significance, surpassing prognostic stratification of ESCC patients based on HMGB1 positivity alone. This striking association led us to set up models to test whether cancer-derived HMGB1 could shape tumor microenvironment via modulation on B cells. Overexpression of HMGB1 in ESCC cell lines (KYSE510 and EC18) enhanced proliferation and migration of B cells. Transcriptomic analysis showed that migratory B cells exhibited high enrichment of proangiogenic genes. VEGF expression in proliferating B cells was induced upon co-culture of HMGB1-overexpressing tumor cells and B cells. Secretome array profiling of conditioned media (CM) from the co-culture revealed rich expression of proangiogenic proteins. Consequently, incubation of human umbilical vein endothelial cells with CM promoted angiogenesis in tube formation and migration assays. HMGB1 inhibitor, glycyrrhizin, abolishes all the observed proangiogenic phenotypes. Finally, co-injection of B cells and CM with HMGB1-overexpressing tumor cells, but not with glycyrrhizin, significantly enhanced tumor growth associated with increased microvascular density in ESCC xenograft mice model. Our results indicate that cancer-derived HMGB1 elevates angiogenesis in ESCC by shifting the balance toward proangiogenic signals in proliferating B cells. Supplementary Information The online version contains supplementary material available at 10.1007/s10456-021-09819-0.

Licochalcone A (LA), a flavonoid found in licorice, has anticancer, antioxidant, anti-inflammatory, and neuroprotective properties. Here, we explored the effect of injecting LA into the tail vein of middle-aged C57BL/6 mice on their cognitive ability as measured by the Morris water maze (MWM) test and cerebral blood flow (CBF). The related mechanisms were assessed via RNA-seq, and T (CD3e+) and B (CD45R/B220+) cells in the spleen and whole blood were quantified via flow cytometry. LA improved the cognitive ability, according to the MWM test results, and upregulated the CBF level of treated mice. The RNA-seq results indicate that LA affected the interleukin (IL)-17 signaling pathway, which is related to T- and B-cell proliferation, and the flow cytometry data suggest that LA promoted T- and B-cell proliferation in the spleen and whole blood. We also performed immune reconstruction via a tail vein injection of lymphocytes into B-NDG (NOD-PrkdcscidIl2rgtm1/Bcge) mice before treating them with LA. We tested cognitive ability by subjecting these animals to new object recognition tests and quantified the splenic and whole blood T and B cells. Cognitive ability improved after immune reconstruction and LA treatment, and LA promoted T- and B-cell proliferation in the spleen and whole blood. This study demonstrates that LA, by activating the IL-17 signaling pathway, promotes T- and B-cell proliferation in the spleen and whole blood of mice and improves cognitive ability. Thus, LA may have immune-modulating therapeutic potential for improving cognition.

Lupus nephritis (LN) is a frequent and severe manifestation of SLE. Along the decades, the epidemiology of LN and its clinical presentation have been changing. However, even though retrospective cohort studies report a decreased mortality rate and an improvement in the disease prognosis, the percentage of patients progressing into end stage renal disease (ESRD) keeps steady despite the improvements in therapeutic strategies. Current in-use medications have been available for decades now, yet over the years, regimens for optimizing their efficacy and minimizing toxicity have been developed. Therapeutic research is now moving towards the direction of precision medicine and several new drugs, targeting selectively different pathogenetic pathways, are currently under evaluation with promising results. In this review, we address the main changes and persistent unmet needs in LN management throughout the past decades, with a focus on prognosis and upcoming treatments.

Background: Marek’s disease virus (MDV), a highly oncogenic α-herpesvirus, is the etiological agent of Marek’s disease (MD) in chickens. The antiviral activity of vaccine-induced immunity against MD reduces the level of early cytolytic infection, production of cell-free virions in the feather follicle epithelial cells (FFE), and lymphoma formation. Despite the success of several vaccines that have greatly reduced the economic losses from MD, the mechanism of vaccine-induced immunity is poorly understood. Methods: To provide insight into possible role of B cells in vaccine-mediated protection, we bursectomized birds on day of hatch and vaccinated them eight days later. The birds were challenged 10 days post vaccination with or without receiving adoptive lymphocytes from age-matched control birds prior to inoculation. The study also included vaccinated/challenged and non-vaccinated challenged intact birds. Flowcytometric analysis of PBMN cells were conducted twice post bursectomy to confirm B cell depletion and assess the effect of surgery on T cell population. Immunohistochemical analysis and viral genome copy number assessment in the skin samples at termination was performed to measure the replication rate of MDV in the FFE of the skin tissues of the challenged birds. Results: The non-vaccinated/challenged birds developed typical clinical signs of MD while the vaccinated/challenged and bursectomized, vaccinated/challenged groups with or without adoptive lymphocyte transfer, were fully protected with no sign of transient paralysis, weight loss, or T cell lymphomas. Immunohistochemical analysis and viral genome copy number evaluation in the skin samples revealed that unlike the vaccinated/challenged birds a significant number of virus particles were produced in the FFE of the non-vaccinated/challenged birds at termination. In the bursectomized, vaccinated/challenged groups, only a few replicating virions were detected in the skin of birds that received adoptive lymphocytes prior to challenge. Conclusions: The study shows that B cells do not play a critical role in MD vaccine-mediated immunity.

Background: Delayed-release dimethyl fumarate (DMF) demonstrates sustained efficacy and safety for relapsing forms of MS. Absolute lymphocyte count (ALC) is reduced initially, then stabilizes on treatment. Objective: PROCLAIM, a 96-week, prospective, open-label, phase 3b study, assessed lymphocyte subsets and immunoglobulin (Ig) levels during 48 and 96 weeks (W) of DMF treatment. Methods: Patients received 240 mg DMF BID. Endpoints: lymphocyte subset count changes (primary); Ig isotypes and ALC changes (secondary); adverse events and relationship between ALC changes and ARR/EDSS (exploratory); and neurofilament assessment (ad hoc). Results: Of 218 patients enrolled, 158 (72%) completed the study. Median ALC decreased 39% from baseline to W96 (BL–W96), stabilizing above the lower limit of normal (baseline: 1.82 × 109/L; W48: 1.06 × 109/L; W96: 1.05 × 109/L). CD4 + and CD8 + T cells correlated highly with ALC from BL–W96 ( p + and CD8 + T cells increased, whereas CD4 + and CD8 + central and effector memory T cells decreased. Total IgA, IgG, IgM, and IgG1–4 subclass levels remained stable. Adverse event rates were similar across ALC subgroups. ARR, EDSS, and neurofilament were not correlated with ALCs. Conclusion: Lymphocyte decreases with DMF were maintained over treatment, yet immunoglobulins remained stable. No increase in infection incidence was observed in patients with or without lymphopenia. Support: Biogen

Interleukin (IL)-12 family member is a heterodimer glycoprotein, composed of two covalently linked subunits, α and β chains. The α subunit consists of IL-23p19, IL-27p28, and IL-12p35, and the β subunit includes IL-12p40 and Epstein-Barr virus-induced gene (Ebi3). IL-39 is a new heterodimeric IL-12 family member composed of IL-23p19 and Ebi3 subunits. IL-39 is secreted by lipopolysaccharide-stimulated B cells. Other immune cells, such as dendritic cells and macrophages, express IL-39 mRNA. In lupus-like mice, GL7+B cells and CD138+plasma cells are highly activated and widely expressed, promoting high expression of IL-39. IL-39 mediates inflammatory responses through binding to a heterodimer of IL-23R/gp130 receptor and activation of signal transducer and activator of transcription (STAT)1/STAT3 signal molecules. The serum levels of IL-39 were significantly increased in patients with acute coronary syndrome compared with patients with normal coronary arteries. This review discusses the biological characteristics, receptor, and signal pathway as well as biological activity of IL-39 and its potential role in inflammation and other diseases.

Age‐related reductions in vaccine‐induced B cells in aging indicate that germinal centers (GCs), the anatomical site where the development of humoral responses takes place, may lose efficacy with age. We have investigated the baseline follicular and GC composition in nonhuman primates (NHPs) with respect to their age. There was a marked reduction in follicular area in old animals. We found significantly lower normalized numbers of follicular PD1hi CD4 T (Tfh) and proliferating (Ki67hi) GC B cells with aging, a profile associated with significantly higher numbers of potential follicular suppressor FoxP3hiLag3hi CD4 T cells. Furthermore, a positive correlation was found between Tfh and follicular CD8 T cells (fCD8) only in young animals. Despite the increased levels of circulating preinflammatory factors in aging, young animals had higher numbers of monocytes and granulocytes in the follicles, a profile negatively associated with numbers of Tfh cells. Multiple regression analysis showed an altered association between GC B cells and other GC immune cell populations in old animals suggesting a differential mechanistic regulation of GC activity in aging. Our data demonstrate defective baseline GC composition in old NHPs and provide an immunological base for further understanding the adaptive humoral responses with respect to aging., Steady‐state germinal center immune reactivity is compromised in aged NHPs. This loss of reactivity is characterized by changes in many GC associated cell populations including Tfh, B cells, and follicular Tregs.

B cells play both protective and pathogenic roles in T cell-mediated autoimmune diseases by releasing regulatory vs. pathogenic cytokines. B cell-depleting therapy has been attempted in various autoimmune diseases but its efficacy varies and can even worsen symptoms due to depletion of B cells releasing regulatory cytokines along with B cells releasing pathogenic cytokines. Here, we report that S-nitrosoglutathione (GSNO) and GSNO-reductase (GSNOR) inhibitor N6022 drive upregulation of regulatory cytokine (IL-10) and downregulation of pathogenic effector cytokine (IL-6) in B cells and protected against the neuroinflammatory disease of experimental autoimmune encephalomyelitis (EAE). In human and mouse B cells, the GSNO/N6022-mediated regulation of IL-10 vs. IL-6 was not limited to regulatory B cells but also to a broad range of B cell subsets and antibody-secreting cells. Adoptive transfer of B cells from N6022 treated EAE mice or EAE mice deficient in the GSNOR gene also regulated T cell balance (Treg > Th17) and reduced clinical disease in the recipient EAE mice. The data presented here provide evidence of the role of GSNO in shifting B cell immune balance (IL-10 > IL-6) and the preclinical relevance of N6022, a first-in-class drug targeting GSNOR with proven human safety, as therapeutics for autoimmune disorders including multiple sclerosis., Graphical abstract Image 1, Highlights • GSNO and GSNOR inhibitor (N6022) upregulates IL-10 and downregulates IL-6 in B cells. • GSNO/N6022-mediated cytokine regulation occurs in a broad range of B cell subsets. • GSNO/N6022 treatment ameliorates autoimmune disease of EAE. • B cell transfer from N6022-treated or GSNOR null EAE mice to EAE mice shifts T cell balance (Treg > Th17) and alleviates EAE. • The data provide the first insight into the therapeutic potential of GSNO/N6022 targeting B cells in multiple sclerosis.

Engagement of Fcγ receptor IIb (FcγRIIb) suppresses B cell activation and represents a promising target for therapy in autoimmunity. Obexelimab is a non-depleting anti-human CD19 mAb with an Fc region engineered to have high affinity for human FcγRIIb, thereby co-engaging BCR and FcγRIIb. To assess its ability to suppress B cell activation in vivo, we generated non-autoimmune-prone C57BL/6 (B6) and SLE-prone NZM 2328 (NZM) mice in which the human FcγRIIb extracellular domain was knocked into the mouse Fcgr2b locus (B6.hRIIb and NZM.hRIIb mice, respectively, the latter retaining features of SLE). XENP8206, a mAb which bears the same FcγRIIb-enhanced human Fc domain as does obexelimab but which recognizes murine CD19 rather than human CD19, inhibited in vitro BCR-triggered activation of B cells from both B6.hRIIb and NZM.hRIIb mice. Following administration of XENP8206 to B6.hRIIb or NZM.hRIIb mice, B cell numbers in the spleen and lymph nodes remained stable but became hyporesponsive to BCR-triggered activation for at least 14 days. These findings demonstrate proof-of-principle that pharmacologic co-engagement of BCR and human FcγRIIb inhibits B cell activation in non-autoimmune and SLE-prone hosts while preserving B cell numbers. These observations lay a strong foundation for clinical trials in human SLE with agents that co-engage BCR and FcγRIIb. Moreover, B6.hRIIb and NZM.hRIIb should serve as powerful in vivo models in the elucidation of the cellular and molecular underpinnings of the changes induced by BCR/FcγRIIb co-engagement., Highlights • We generated non-autoimmune B6.hRIIb and SLE-prone NZM.hRIIb knockin mice for the human FcγRIIb extracellular domain. • XENP8206 is an anti-murine CD19 mAb engineered to have high affinity for human FcγRIIb. • XENP8206 inhibited in vitro BCR-triggered activation of B cells from both B6.hRIIb and NZM.hRIIb mice. • XENP8206 inhibited in vivo BCR-triggered activation of B cells while preserving B cell numbers. • These observations lay a strong foundation for clinical trials in human SLE with agents that co-engage BCR and FcγRIIb.

T cells secrete bioactive extracellular vesicles (EVs), but the potential biological effects of CD4+ T cell EVs are not clear. The main purpose of this study is to investigate the effects of CD4+ T cell–derived EVs on B cell responses and examine their role in antigen‐mediated humoral immune responses. In this study, CD4+ T cell EVs are purified from activated CD4+ T cells in vitro. After immunization with the Hepatitis B surface antigen (HBsAg) vaccine, CD4+ T cell EVs‐treated mice show stronger humoral immune responses, which is indicated by a greater Hepatitis B surface antibody (HBsAb) level in serum and a greater proportion of plasma cells in bone marrow. In addition, it is found that EVs released from activated CD4+ T cells play an important role in B cell responses in vitro, which significantly promote B cell activation, proliferation, and antibody production. Interestingly, antigen‐specific CD4+ T cell EVs are found to be more efficient than control EVs in enhancing B cell responses. Furthermore, it is shown that CD40 ligand (CD40L) is involved in CD4+ T cell EVs‐mediated B cell responses. Overall, the results have demonstrated that CD4+ T cell EVs enhance B cell responses and serve as a novel immunomodulator to promote antigen‐specific humoral immune responses., CD4+ T cells release bioactive extracellular vesicles. CD4+ T cells extracellular vesicles (EVs) can enhance B cell responses by CD40 ligand (CD40L), which significantly promote B cell activation, proliferation, and antibody production in vitro. In addition, the application of CD4+ T cell EVs further promotes antigen‐specific humoral immune responses in Hepatitis B surface antigen (HBsAg)‐immunized mice.

Anti-CD20-mediated B-cell depletion effectively reduces acute multiple sclerosis (MS) flares. Recent data shows that antibody-mediated extinction of B cells as a lasting immune suppression, harbors the risk of developing humoral deficiencies over time. Accordingly, more selective, durable and reversible B-cell-directed MS therapies are needed. We here tested inhibition of Bruton’s tyrosine kinase (BTK), an enzyme centrally involved in B-cell receptor signaling, as the most promising approach in this direction. Using mouse models of MS, we determined that evobrutinib, the first BTK inhibiting molecule being developed, dose-dependently inhibited antigen-triggered activation and maturation of B cells as well as their release of pro-inflammatory cytokines. Most importantly, evobrutinib treatment functionally impaired the capacity of B cells to act as antigen-presenting cells for the development of encephalitogenic T cells, resulting in a significantly reduced disease severity in mice. In contrast to anti-CD20, BTK inhibition silenced this key property of B cells in MS without impairing their frequency or functional integrity. In conjunction with a recent phase II trial reporting that evobrutinib is safe and effective in MS, our mechanistic data highlight therapeutic BTK inhibition as a landmark towards selectively interfering with MS-driving B-cell properties. Electronic supplementary material The online version of this article (10.1007/s00401-020-02204-z) contains supplementary material, which is available to authorized users.

B cells are a target of Salmonella infection, allowing bacteria survival without inducing pyroptosis. This event is due to downregulation of Nlrc4 expression and lack of inflammasome complex activation, which impairs the secretion of IL-1β. YAP phosphorylation is required for downregulation of Nlrc4 in B cells during Salmonella infection; however, the microorganism’s mechanisms underlying the inhibition of the NLRC4 inflammasome in B cells are not fully understood. Our findings demonstrate that the Salmonella effector SopB triggers a signaling cascade involving PI3K, PDK1 and mTORC2 that activates Akt with consequent phosphorylation of YAP. When we deleted sopB in Salmonella, infected B cells that lack Rictor, or inhibited the signaling cascade using a pharmacological approach, we were able to restore the function of the NLRC4 inflammasome in B cells and the ability to control the infection. Furthermore, B cells from infected mice exhibited activation of Akt and YAP phosphorylation, suggesting that Salmonella also triggers this pathway in vivo. In summary, our data demonstrate that the Salmonella effector inositide phosphate phosphatase SopB triggers the PI3K-Akt-YAP pathway to inhibit the NLRC4 inflammasome in B cells. This study provides further evidence that Salmonella triggers cellular mechanisms in B lymphocytes to manipulate the host environment by turning it into a survival niche to establish a successful infection.

// Seung Seok Han 1, 2 , Seung Hee Yang 2 , Hyung Ah Jo 1 , Yun Jung Oh 2 , Minkyoung Park 2 , Joo Young Kim 2 , Hajeong Lee 1, 2 , Jung Pyo Lee 1, 2, 3 , Sang-Ho Lee 4 , Kwon Wook Joo 1, 2 , Chun Soo Lim 1, 3 , Yon Su Kim 1, 2 and Dong Ki Kim 1, 2 1 Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea 2 Kidney Research Institute, Seoul National University, Seoul, Korea 3 Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, Korea 4 Department of Internal Medicine, College of medicine, Kyung Hee University, Seoul, Korea Correspondence to: Dong Ki Kim, email: dkkim73@gmail.com Keywords: APRIL; autoimmunity; BAFF; B cells; membranous nephropathy Received: July 03, 2017 Accepted: November 14, 2017 Published: December 14, 2017 ABSTRACT Background: Based on the fact that B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) have a regulatory role in B cell biology, excessive levels of these cytokines can promote autoimmune pathogenesis. However, the expression and implication remain unresolved in cases of membranous nephropathy (MN). Results: The plasma BAFF levels of the primary MN patients were higher than those of healthy controls but lower than those of secondary MN patients, whereas the APRIL levels were similar between the MN patients and healthy controls. The BAFF levels were higher in relapse cases, whereas the APRIL levels were higher in the patients who did not experience remission compared with the counterpart patients. The ectopic expression of BAFF and APRIL was observed in the glomeruli or circulating B cells of MN patients, and this high expression trend was similar to that of lupus patients. Conclusions: Expression profile of BAFF and APRIL in MN is similar to that of other autoimmune disease, which affects the kidney outcomes. Methods: Plasma BAFF and APRIL levels were measured upon kidney biopsy in patients with primary ( n = 89) and secondary MN ( n = 13), and the results were compared with the levels in healthy controls ( n = 111). The kidney outcomes (e.g., remission and relapse) were traced for the median of 3 years. Aberrant expression of the cytokines was evaluated in the kidney and circulating B cells using immunohistochemistry and flow cytometry analyses, respectively.

Background: B cells may be involved in the pathophysiology of multiple sclerosis (MS). Inebilizumab (formerly MEDI-551) binds to and depletes CD19+ B cells. Objectives: To assess safety, tolerability, pharmacokinetics, pharmacodynamics and immunogenicity of inebilizumab in adults with relapsing MS. Methods: This phase 1 trial randomised 28 patients 3:1 (21, inebilizumab; 7, placebo) to inebilizumab (2 intravenous (IV) doses, days 1 and 15: 30, 100 or 600 mg; or single subcutaneous (SC) dose on day 1: 60 or 300 mg) or matching placebo, with follow-up until at least week 24 or return of CD19+ B-cell count to ⩾80 cells/µL. Results: Complete B-cell depletion was observed across all doses. Infusion/injection (grade 1/2) reactions occurred in 6/15 patients receiving inebilizumab IV, 2/5 placebo IV and 1/6 inebilizumab SC. Serious adverse events occurred in three patients receiving inebilizumab: pyrexia, mixed-drug intoxication (unrelated to inebilizumab; resulted in death) and urinary tract infection. Mean number of cumulative new gadolinium-enhancing lesions over 24 weeks was 0.1 with inebilizumab versus 1.3 with placebo; mean numbers of new/newly enlarging T2 lesions were 0.4 and 2.4, respectively. Conclusion: Inebilizumab had an acceptable safety profile in relapsing MS patients and showed a trend in reductions in new/newly enlarging and gadolinium-enhancing lesions.

// Arcangelo Liso 1 , Stefano Castellani 1 , Francesca Massenzio 1 , Rosa Trotta 1 , Alessandra Pucciarini 2 , Barbara Bigerna 2 , Pasquale De Luca 3 , Pietro Zoppoli 4 , Filippo Castiglione 5 , Maria Concetta Palumbo 5 , Fabrizio Stracci 6 , Matteo Landriscina 1,7 , Giorgina Specchia 8 , Leon A. Bach 9,10 , Massimo Conese 1 and Brunangelo Falini 2 1 Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy 2 Institute of Haematology, University of Perugia, Perugia, Italy 3 Stazione Zoologica A. Dohrn, Naples, Italy 4 Dipartimento di Medicina Sperimentale e Clinica, Universita degli Studi Magna Graecia, Catanzaro, Italy 5 Institute for Applied Computing, National Research Council of Italy, Rome, Italy 6 Department of Experimental Medicine, Section of Public Health, University of Perugia, Perugia, Italy 7 Laboratory of Preclinical and Translational Research, IRCCS, Referral Cancer Center of Basilicata, Rionero in Vulture, Italy 8 Institute of Hematology, University of Bari, Bari, Italy 9 Department of Medicine, Alfred Hospital, Monash University, Melbourne, Australia 10 Department of Endocrinology and Diabetes, Alfred Hospital, Melbourne, Australia Correspondence to: Arcangelo Liso, email: // Massimo Conese, email: // Keywords : apoptosis, B cells, chemotaxis, dendritic cells, hyperthermia, Immunology and Microbiology Section, Immune response, Immunity Received : April 16, 2017 Accepted : May 12, 2017 Published : June 01, 2017 Abstract Fever plays a role in activating innate immunity while its relevance in activating adaptive immunity is less clear. Even brief exposure to elevated temperatures significantly impacts on the immunostimulatory capacity of dendritic cells (DCs), but the consequences on immune response remain unclear. To address this issue, we analyzed the gene expression profiles of normal human monocyte-derived DCs from nine healthy adults subjected either to fever-like thermal conditions (39°C) or to normal temperature (37°C) for 180 minutes. Exposure of DCs to 39°C caused upregulation of 43 genes and downregulation of 24 genes. Functionally, the up/downregulated genes are involved in post-translational modification, protein folding, cell death and survival, and cellular movement. Notably, when compared to monocytes, DCs differentially upregulated transcription of the secreted protein IGFBP-6, not previously known to be specifically linked to hyperthermia. Exposure of DCs to 39°C induced apoptosis/necrosis and resulted in accumulation of IGFBP-6 in the conditioned medium at 48 h. IGFBP-6 may have a functional role in the hyperthermic response as it induced chemotaxis of monocytes and T lymphocytes, but not of B lymphocytes. Thus, temperature regulates complex biological DC functions that most likely contribute to their ability to induce an efficient adaptive immune response.

// Julia Alles 1 , Nicole Ludwig 1 , Stefanie Rheinheimer 1 , Petra Leidinger 1 , Friedrich A. Grasser 2 , Andreas Keller 3 and Eckart Meese 1 1 Institute of Human Genetics, Saarland University, 66421 Homburg, Germany 2 Institute of Virology, Saarland University, 66421 Homburg, Germany 3 Chair for Clinical Bioinformatics, Saarland University, 66123 Saarbrucken, Germany Correspondence to: Julia Alles, email: ju.al@mx.uni-saarland.de Keywords: B cells, microRNA, miR-148a, SOS, ERK Received: March 15, 2017 Accepted: April 24, 2017 Published: May 07, 2017 ABSTRACT Although microRNAs have been recognized as central cellular regulators, there is an evident lack of knowledge about their targets. Here, we analyzed potential target genes for miR-148a functioning in Ras signaling in B cells, including SOS1 and SOS2. A dual-luciferase reporter assay showed significantly decreased luciferase activity upon ectopic overexpression of miR-148a in HEK-293T cells that were co-transfected with the 3′UTR of either SOS1 or SOS2. Each of the 3′UTRs of SOS1 and SOS2 contained two binding sites for miR-148a both of which were necessary for the decreased luciferase activity. MiR-148a overexpression in HEK-293T lead to significantly reduced levels of both endogenous SOS1 and SOS2 proteins. Likewise, reduced levels of SOS proteins were found in two B cell lines that were transfected with miR-148a. The level of ERK1/2 phosphorylation as one of the most relevant downstream members of the Ras/ERK signaling pathway was also reduced in cells with miR-148a overexpression. The data show that miR-148a impairs the Ras/ERK signaling pathway via SOS1 and SOS2 proteins in B cells.

Combination antiretroviral therapies (cART) can lead to normal life expectancy in HIV-infected persons, and people aged >50 yrs represent the fastest growing HIV group. Although HIV and aging are independently associated with impaired humoral immunity, immune status in people aging with HIV is relatively unexplored. In this study influenza vaccination was used to probe age associated perturbations in the B cell compartment of HIV-negative “healthy controls” (HC) and virologically controlled HIV-infected participants on cART (HIV) (n=124), grouped by age as young (

// Viswa Teja Colluru 1,2 and Douglas G. McNeel 1,2 1 Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA 2 Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, USA Correspondence to: Douglas G. McNeel, email: // Keywords : DNA vaccine, B cells, dendritic cells, direct presentation, Immunology and Microbiology Section, Immune response, Immunity Received : July 26, 2016 Accepted : September 16, 2016 Published : September 21, 2016 Abstract In spite of remarkable preclinical efficacy, DNA vaccination has demonstrated low immunogenicity in humans. While efforts have focused on increasing cross-presentation of DNA-encoded antigens, efforts to increase DNA vaccine immunogenicity by targeting direct presentation have remained mostly unexplored. In these studies, we compared the ability of different APCs to present antigen to T cells after simple co-culture with plasmid DNA. We found that human primary peripheral B lymphocytes, and not monocytes or in vitro derived dendritic cells (DCs), were able to efficiently encode antigen mRNA and expand cognate tumor antigen-specific CD8 T cells ex vivo . Similarly, murine B lymphocytes co-cultured with plasmid DNA, and not DCs, were able to prime antigen-specific T cells in vivo. Moreover, B lymphocyte-mediated presentation of plasmid antigen led to greater Th1-biased immunity and was sufficient to elicit an anti-tumor effect in vivo . Surprisingly, increasing plasmid presentation by B cells, and not cross presentation of peptides by DCs, further augmented traditional plasmid vaccination. Together, these data suggest that targeting plasmid DNA to B lymphocytes, for example through transfer of ex vivo plasmidloaded B cells, may be novel means to achieve greater T cell immunity from DNA vaccines.

// Yanxia Lu 1 , Crystal Tze Ying Tan 2 , Ma Shwe Zin Nyunt 3 , Esther Wing Hei Mok 2 , Xavier Camous 2 , Hassen Kared 2 , Tamas Fulop 4 , Liang Feng 5 , Tze Pin Ng 3,* and Anis Larbi 2,4* 1 Department of Clinical Psychology and Psychiatry/School of Public Health, Zhejiang University College of Medicine, Hangzhou, China 2 Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore 3 Gerontology Research Programme, Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 4 Geriatrics Division, Department of Medicine, Research Center on Aging, University of Sherbrooke, Sherbrooke, Quebec, Canada 5 Graduate Medical School, Duke-National University of Singapore, Singapore * These authors have contributted equally to this work Correspondence to: Anis Larbi, email: // Keywords : inflammation; immunosenescence; frailty risk; T cell subsets; B cells; Gerotarget Received : November 18, 2015 Accepted : April 10, 2016 Published : April 22, 2016 Abstract Chronic systematic inflammation and reduced immune system fitness are considered potential contributing factors to the development of age-related frailty, but the underlying mechanisms are poorly defined. This exploratory study aimed to identify frailty-related inflammatory markers and immunological phenotypes in a cohort of community-dwelling adults aged ≥ 55 years. Frailty was assessed using two models, a Frailty Index and a categorical phenotype, and correlated with levels of circulating immune biomarkers and markers of senescence in immune cell subsets. We identified eight serological biomarkers that were associated with frailty, including sgp130, IL-2Rα, I-309, MCP-1, BCA-1, RANTES, leptin, and IL-6R. Frailty Index was inversely predicted by the frequency of CD3+, CD45RA+, and central memory CD4 cells, and positively predicted by the loss of CD28 expression, especially in CD8+ T cells, while frailty status was predicted by the frequency of terminal effector CD8+ T cells. In γ/δ T cells, frailty was negatively associated with CD27, and positively associated with IFNγ+TNFα- secretion by γ/δ2+ cells and IFNγ-TNFα+ secretion by γ/δ2- cells. Increased numbers of exhausted and CD38+ B cells, as well as CD14+CD16+ inflammatory monocytes, were also identified as frailty-associated phenotypes. This pilot study supports an association between inflammation, cellular immunity, and the process of frailty. These findings have significance for the early identification of frailty using circulating biomarkers prior to clinical manifestations of severe functional decline in the elderly.

International audience; Pax5 is the guardian of the B cell identity since it primes or enhances the expression of B cell specific genes and concomitantly represses the expression of B cell inappropriate genes. The tight regulation of Pax5 is therefore required for an efficient B cell differentiation. A defect in its dosage can translate into immunodeficiency or malignant disorders such as leukemia or lymphoma. Pax5 is expressed from two different promoters encoding two isoforms that only differ in the sequence of their first alternative exon. Very little is known regarding the role of the two isoforms during B cell differentiation and the regulation of their expression. Our work aims to characterize the mechanisms of regulation of the expression balance of these two isoforms and their implication in the B cell differentiation process using murine ex vivo analyses. We show that these two isoforms are differentially regulated but have equivalent function during early B cell differentiation and may have functional differences after B cell activation. The tight control of their expression may thus reflect a way to finely tune Pax5 dosage during B cell differentiation process.

Background:Staphylococcus pseudintermedius is an opportunistic pathogen that is the major cause of pyoderma affecting dogs. Conventional antimicrobial treatment for infections caused by this organism have failed in recent years due to widespread resistance and alternative treatment strategies are a high priority. Protein A encoded in Staphylococcus aureus by spa protects the bacterium by binding IgG and acts as a superantigen. Staphylococcus pseudintermedius possess two genes orthologous to S. aureus spa, spsP, and spsQ. Methods: SpsQ and SpsQ-M, a non-toxigenic SpsQ, were cloned and expressed as recombinant proteins and their cytotoxic effect on canine B cells was measured. The neutralizing ability of antibody raised against them in clinically healthy dogs was evaluated. Results: S. pseudintermedius SpsQ induced apoptosis of canine B cells. Specific amino acid substitutions diminished SpsQ-M binding to immunoglobulin and its super-antigenic activity, while its antigenicity was maintained. This recombinant, non-toxigenic S. pseudintermedius SpsQ stimulated the production of antibodies in dogs that specifically reacted with SpsQ and greatly diminished its cytotoxic effect on canine B cells. Conclusions: The production of neutralizing antibody suggests that attenuated, non-toxic SpsQ produced in this study is a good candidate for inclusion in a vaccine for use in the treatment and prevention of S. pseudintermedius infections. Abbreviations: SpA: Staphylococcus aureus protein A; SpsP: Staphylococcus pseudintermedius protein A; SpsQ: Staphylococcus pseudintermedius protein A; SpsQ-M: attenuated Staphylococcus pseudintermedius protein A; MRSP: methicillin resistant Staphylococcus pseudintermedius; IgA: immunoglobulin A; IgG: immunoglobulin G; IgM: immunoglobulin M; VH: variable region of immunoglobulin heavy chain; IgBD: immunoglobulin binding domains; MFI: mean fluorescent intensity; SEM: standard error of the mean; PBMC: Peripheral blood mononuclear cells; CD21: complement receptor type 2; ST: Sequence type; OD: Optical density; ORF: open reading frame; PBS: Phosphate buffered saline; Tween 20: Polyethylene glycol sorbitan monolaurate 20; HRP: horseradish peroxidase; TMB- 3,3',5,5'-Tetramethylbenzidine

The involvement of proteoglycans (PGs) in EBV-host interactions and lymphomagenesis remains poorly investigated. In this study, expression of major proteoglycans (syndecan-1, glypican-1, perlecan, versican, brevican, aggrecan, NG2, serglycin, decorin, biglycan, lumican, CD44), heparan sulphate (HS) metabolic system (EXT1/2, NDST1/2, GLCE, HS2ST1, HS3ST1/2, HS6ST1/2, SULF1/2, HPSE) and extracellular matrix (ECM) components (collagen 1A1, fibronectin, elastin) in primary B cells and EBV carrying cell lines with different phenotypes, patterns of EBV-host cell interaction and viral latency stages (type I-III) was investigated. Primary B cells expressed a wide repertoire of PGs (dominated by serglycin and CD44) and ECM components. Lymphoblastoid EBV+ B cell lines (LCLs) showed specific PG expression with down-regulation of CD44 and ECM components and up-regulation of serglycin and perlecan/HSPG2. For Burkitt's lymphoma cells (BL), serglycin was down-regulated in BL type III cells and perlecan in type I BL cells. The biosynthetic machinery for HS was active in all cell lines, with some tendency to be down-regulated in BL cells. 5'-aza-dC and/or Trichostatin A resulted in transcriptional upregulation of the genes, suggesting that low expression of ECM components, proteoglycan core proteins and HS biosynthetic system is due to epigenetic suppression in type I cells. Taken together, our data show that proteoglycans are expressed in primary B lymphocytes whereas they are not or only partly expressed in EBV-carrying cell lines, depending on their latency type program.

// Changyou Wu 1 , Zitao Li 1 , Xiaoying Fu 1 , Sifei Yu 1 , Suihua Lao 2 and Binyan Yang 1 1 Institute of Immunology, Zhongshan School of Medicine, Guangdong Provincial Key Laboratory of Organ Donation and Transplant Immunology, Sun Yat-Sen University, Guangzhou, China 2 Chest Hospital of Guangzhou, Guangzhou, China Correspondence to: Changyou Wu, email: // Keywords : NKT cells, tuberculosis, IL-21, B cells, immunoglobulins, Immunology and Microbiology Section, Immune response, Immunity Received : July 13, 2015 Accepted : September 05, 2015 Published : September 21, 2015 Abstract Natural killer T (NKT) cells from mouse and human play an important role in the immune responses against Mycobacterium tuberculosis . However, the function of CD3 + TCRvβ11 + NKT cells at the local site of M. tuberculosis infection remains poorly defined. In the present study, we found that after stimulation with M. tuberculosis antigens, NKT cells isolated from tuberculosis (TB) pleural fluid mononuclear cells (PFMCs) produced IL-21 and other cytokines including IFN-γ, TNF-α, IL-2 and IL-17. IL-21-expressing NKT cells in PFMCs displayed effector memory phenotype, expressing CD45RO high CD62L low CCR7 low . Moreover, NKT cells expressed high levels of CXCR5 and all of IL-21-expressing NKT cells co-expressed CXCR5. The frequency of BCL-6-expression was higher in IL-21-expressing but not in non-IL-21-expressing CD3 + TCRvβ11 + NKT cells. Sorted CD3 + TCRvβ11 + NKT cells from PFMCs produced IFN-γ and IL-21 after stimulation, which expressed CD40L. Importantly, CD3 + TCRvβ11 + NKT cells provided help to B cells for the production of IgG and IgA. Taken together, our data demonstrate that CD3 + TCRvβ11 + NKT cells from a local site of M. tuberculosis infection produce IL-21, express CXCR5 and CD40L, help B cells to secrete IgG and IgA, and may participate in local immune responses against M. tuberculosis infection.

The tumor suppressor p53 is a transcription factor that coordinates the cellular response to DNA damage. Here we provide an integrated analysis of p53 genomic occupancy and p53-dependent gene regulation in the splenic B and non-B cell compartments of mice exposed to whole-body ionizing radiation, providing insight into general principles of p53 activity in vivo. In unstressed conditions, p53 bound few genomic targets; induction of p53 by ionizing radiation increased the number of p53 bound sites, leading to highly overlapping profiles in the different cell types. Comparison of these profiles with chromatin features in unstressed B cells revealed that, upon activation, p53 localized at active promoters, distal enhancers, and a smaller set of unmarked distal regions. At promoters, recognition of the canonical p53 motif as well as binding strength were associated with p53-dependent transcriptional activation, but not repression, indicating that the latter was most likely indirect. p53-activated targets constituted the core of a cell type-independent response, superimposed onto a cell type-specific program. Core response genes included most of the known p53-regulated genes, as well as many new ones. Our data represent a unique characterization of the p53-regulated response to ionizing radiation in vivo.