scholarly journals High Peripheral Blood Circulating BDNF Levels Are Associated with Good Prognosis in CLL Patients; A CXCR-4 Dependent Effect?

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5562-5562
Author(s):  
David Azoulay ◽  
Yair Herishanu ◽  
Mika Shapiro ◽  
Yarden Brenshaft ◽  
Celia Suriu ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
B Cells ◽  
Serum Levels ◽  
Surface Expression ◽  
Independent Effect ◽  
Total Serum ◽  
Healthy Controls ◽  
Disease Prognosis ◽  
And Migration

Abstract Introduction: BDNF is a neuronal growth factor that previously showed to exert survival effect in B cells. The role of BDNF in CLL is unknown. Objectives: To study the circulating levels of BDNF in CLL patients and their association with disease prognosis. We also looked for CXCR-4 as a possible mechanisms underlying BDNF effect in CLL. Design and methods: The total BDNF levels and the levels of the BDNF precursor; proBDNF were quantified in the serum of 36 CLL patients and 5 healthy controls by commercial ELISA kits (DY248 and DY3175 DuoSet, respectively, from R&D Systems, Minneapolis, MN, USA). The patients' BDNF levels were correlated to the disease characteristics and clinical course. mRNA and protein expression of the high affinity receptor for BDNF; TrkB were evaluated by real time PCR and flow cytometry respectively. The effect of BDNF on CXCR4 surface expression and migration of CLL cells towards SDF-1 were studied in-vitro. Results: The total serum levels of BDNF in CLL patients was not statistically different compared to healthy controls (mean±SD; 19.9±15.1ng/ml vs. 10.5±9.5ng/ml respectively, p=0.19). Serum proBDNF levels in both CLL patients and healthy controls were under the detection limit of the kit. Within the CLL group we found higher total BDNF levels in patients with mutated immunoglobulin variable heavy-chain (IGHV) status than in patients with unmutated IGHV (25.2±14.6ng/ml vs. 14.1±13.0 in mutated and unmutated status, respectively, p=0.028). We also found higher serum levels of total BDNF in CLL patients in Binet stage A compared to those with a more advance clinical stage (mean±SD ; 24.5±14.6ng/ml vs. 17.0±16.9 and 10.2±9.6 in A,B and C, respectively, p=0.013). Accordantly, higher BDNF levels were detected in patients who had a clinically stable disease compared to patients who had disease progression and required treatment (23.1±14.7ng/ml vs. 13.4±14.5, respectively, p=0.013). The mRNA levels of the BDNF receptor; TrkB, were twofold lower in CLL cells compared to normal B cells. However, the overall TrkB mRNA transcripts were very low in CLL cells and normal B cells compared to the normalized housekeeping genes of Beta-2-microglobulin and CD19. Likewise, surface expression of TrkB in CLL was undetectable using several commercial monoclonal Abs by flow cytometry. In vitro culture of CLL cells in serum free media for 24h resulted in an increased CXCR4 surface expression and greater apoptosis. Culture of CLL cells in the presence of recombinant BDNF (50ng/ml) resulted in downregulation CXCR-4 surface levels and protection from spontaneous apoptosis, irrespectively of the IGHV mutational status. The effect of BDNF on CXCR4 downregulation was also confirmed at 1h culture as it shows to induce similar effect to SDF-1 (50ng/ml) and additive effect when combined with SDF-1. Finally, possible competition between BDNF and SDF-1 was indicated as pretreatment of CLL cells with BDNF inhibit their migration toward SDF-1. Discussion: Our findings show association between high BDNF levels and favorable disease prognosis in CLL. Undetected TrkB expression in CLL cells is compatible with previous reports showing sequestration of TrkB in normal and malignant B cells and suggests TrkB independent effect of BDNF in CLL. The effect of BDNF on the survival and migration of CLL cells via CXCR-4 needs to be further investigated. Disclosures No relevant conflicts of interest to declare.

scholarly journals THU0034 AUTOREACTIVE B CELLS ESCAPE PERIPHERAL CHECKPOINT IN ANCA-ASSOCIATED VASCULITIS AND SJÖGREN’S SYNDROME

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 230.3-230
Author(s):  
N. Chriti ◽  
M. Boudigou ◽  
E. Porchet ◽  
J. O. Pers ◽  
S. Hillion ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
Healthy Subjects ◽  
Peripheral Tolerance ◽  
Healthy Controls ◽  
Autoreactive B Cells ◽  
Anca Associated Vasculitis

Background:B cells play a central role in many autoimmune diseases (AIDs) including ANCA-associated vasculitis (AAV) and primary Sjögren’s syndrome (pSS). Most of the research that has been conducted on AID has focused on the production, secretion, and pathogenicity of auto-antibodies, but little is known on the characteristics of autoreactive B cells in humans.Objectives:This study aims at characterizing circulating autoantigen (PR3 ou SSA)-specific B-cells in patients with AAV and pSS compared to healthy subjects to better understand their role in thenatural and pathological autoimmunityand define the mechanisms leading to the breakdown of self-tolerance in patients with AID.Methods:First, we developed a new flow-cytometry method to detect circulating auto-reactive B cell based on the specificity of their B-cell receptor (BCR). To study surface phenotype of specific B cells by flow cytometry, blood samples were collected from patient with PR3-ANCA AAV, pSS and from healthy subjects. Functional analysis of antigen-specific B cells was also elicited by in vitro analysis of their capacity to secrete immunoglobulins against SSA or PR3 antigens by ELISPOTResults:Phenotype analysis showed that antigen-specific B cells in patients have a memory phenotype compared with healthy controls (5 to 9% are IgG-expressing memory B cells). It suggests that in AID, theses auto-reactive cells are able to differentiate into IgG isotype-switched cells and escape peripheral tolerance checkpoint but not in healthy subjects. Interestingly, Naturalauto-reactive Bcells are able to secrete only IgM isotype autoantibodies uponin vitrostimulation but not IgG class switched antibodies. In order to better understand what differentiates auto-reactive B cells and the mechanisms leading to pathological autoimmunity, agenomic analysisof the antibody repertoire as well as atranscriptional profilingof these cells by single-cell RNA seq is ongoing to understand further the differences of these autoreactive B cells between healthy subjects and patients with AIDs.Conclusion:We developed a technology to identify and isolate antigen-specific B cells from the peripheral blood of patients with AID. Our results suggest that autoreactive B cells escape peripheral tolerance checkpoint and are able to differentiate into IgG isotype-switched cells in patients with AIDs but not in healthy subjects.References:[1]D. Cornec, A. Berti, A. Hummel, T. Peikert, J.-O. Pers, et U. Specks, « Identification and phenotyping of circulating autoreactive proteinase 3-specific B cells in patients with PR3-ANCA associated vasculitis and healthy controls »,J. Autoimmun., vol. 84, p. 122–131, 2017[2]P. F. Kerkman et al., « Identification and characterisation of citrullinated antigen-specific B cells in peripheral blood of patients with rheumatoid arthritis », Ann. Rheum. Dis., vol. 75, no 6, p. 1170‑1176, juin 2016, doi: 10.1136/annrheumdis-2014-207182.Acknowledgments:with support of vasculitis foundation, CSL Berhing, SFRDisclosure of Interests:None declared

The Role of Surface Immunoglobulin Isotype in Chronic Lymphocytic Leukemia Disease Biology and Clinical Outcome

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2850-2850
Author(s):  
Danielle M. Brander ◽  
Sallie D. Allgood ◽  
Karen M. Bond ◽  
J. Brice Weinberg ◽  
Mark C Lanasa
Keyword(s):  
Flow Cytometry ◽  
B Cells ◽  
Conflicts Of Interest ◽  
Fold Increase ◽  
Surface Expression ◽  
Lymphocytic Leukemia ◽  
Mutation Status ◽  
Immunoglobulin Isotype ◽  
Surface Immunoglobulin

Abstract Abstract 2850 Background: Upon encountering cognate antigen, naïve B cells may undergo germinal center reaction. This results in DNA modification including somatic hypermutations (HSM) of the immunoglobulin heavy chain variable region gene (IGHV) and immunoglobulin class switch recombination (CSR). HSM and CSR are unlinked, but share initiating and mechanistic factors. Prior evidence indicates CLL B cells are antigen experienced; however, half of all CLL patients have an unmutated IGHV and follow more aggressive clinical courses. The biologic importance of the CLL immunoglobulin isotype and CSR in B cell receptor (BCR)-mediated signaling is not well understood. We hypothesized the immunoglobulin isotype and expression density of surface immunoglobulin would correlate with IGHV mutation status and other clinical parameters, and predict BCR responsiveness in vitro. Methods: 195 samples from our CLL specimen repository with detailed clinical and biologic characterization were evaluated. Surface expression of IgD, IgM and IgG was determined using multi-parameter flow cytometry and samples were classified as either IgG+ or IgM+IgD+ co-expressing. An ROC analysis was performed to identify the most discriminate value for dichotomization of IgM surface expression as a function of IGHV mutation status. IgMhiIgD+, and IgMlowIgD+ patients were then analyzed for associations with clinical and biologic parameters. To investigate the biological mechanisms of potential associations, BCR-mediated signaling after isotype specific crosslinking in vitro was measured by quantification of downstream phospho-proteins (SYK, AKT, ERK, MEK1, NFκB) by flow cytometry (phospho-flow). Samples were crosslinked with IgM (or IgG if IgG+), IgD, and isotype control and incubated for 0, 15, 30, 60, and 120 minutes. The extent of phosphorylation at each timepoint was expressed as mean fluorointensity (MFI) of the examined proteins. Crosslinked samples were also analyzed using oligonucleotide microarray gene analysis (GEP) to assess differential transcription. Results: A correlation was identified between the percentage of CLL cells expressing surface IgM and IGHV mutation status (r2=0.33); higher surface expression of IgM correlated with unmutated IGHV. The most discriminate value of IgM expression for prediction of IGHV mutation was 47%, with an area under ROC curve of 0.72. Of the 195 patient samples analyzed, 91 (47%) were IgMhiIgD+; 85 (43%) were IgMlowIgD+; and 19 (10%) were IgG+. IgMhiIgD+ samples showed increased expression of CD38 (p<0.01) and ZAP70 (p<0.05) compared to IgMlowIgD+ samples. Only 1 of 19 IgG+ samples was IGHV unmutated. Neither immunoglobulin isotype nor density correlated with gender, lymphocyte doubling time, age, or Rai stage at diagnosis. There was a trend toward shorter time to first treatment by IgM expression (IgMhiIgD+ 7.9yrs vs. IgMlowIgD+ 9.4yrs) but this was not significant (p=0.09). To date, we have tested the biologic relevance of surface immunoglobulin (sIg) density and isotype in 13 patients using phospho-flow analysis. Crosslinking in the IgMlow patients (sIgM <30%; n=5) demonstrated no change in MFI of tested proteins. Among IgMmod patients (sIg 31–60%; n=2), a maximal 3 fold increase in p-SYK MFI with IgM crosslinking and 3.8 fold increase with IgD crosslinking was observed. In IgMhi samples (sIgM >60%; n=3), there was a maximal 3.5 fold increase in MFI with IgM but no change with IgD crosslinking. In the IgG+ samples (n=3), a maximum 5 fold increase in MFI was observed. Analysis of GEP data is ongoing. Conclusion: Surface expression of IgM in CLL varies considerably between patients. This difference in density of surface IgM expression correlates with markers of clinical risk. Although we do not propose immunoglobulin isotype or expression density as a novel prognostic factor, the findings that high surface expression of IgM in CLL predicts BCR mediated signaling after crosslinking provides insight into CLL immunobiology and disease responsiveness to antigens in the microenvironment. In addition, the observation of significant BCR activation within the IgG+ population (which was predominantly IGHV mutated) suggests that the responsiveness of the BCR to crosslinking may be related to the immunoglobulin isotype and density, and not solely determined by the IGHV mutation status. Disclosures: No relevant conflicts of interest to declare.

scholarly journals TACI Expression and Signaling in Chronic Lymphocytic Leukemia

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Antigoni Mamara ◽  
Anastasios E. Germenis ◽  
Maria Kompoti ◽  
Maria Palassopoulou ◽  
Eudokia Mandala ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Serum Levels ◽  
Lymphocytic Leukemia ◽  
Healthy Controls ◽  
Therapeutic Approaches ◽  
Survival Capacity ◽  
Selection Of

TACI is a membrane receptor of BAFF and APRIL, contributing to the differentiation and survival of normal B cells. Although malignant B cells are also subjected on TACI signaling, there is a remarkable intradisease and interindividual variability of TACI expression in B-cell malignancies. The aim of our study was to explore the possible role of TACI signaling in the biology of chronic lymphocytic leukemia (CLL), including its phenotypic and clinical characteristics and prognosis. Ninety-four patients and 19 healthy controls were studied. CLL patients exhibited variable TACI expression, with the majority of cases displaying low to undetectable TACI, along with low to undetectable BAFF and increased APRIL serum levels compared to healthy controls. CLL cells with high TACI expression displayed a better survival capacity in vitro, when cultured with BAFF and/or APRIL. Moreover, TACI expression was positively correlated with the presence of monoclonal gammopathy and inversely with CD11c expression. Therefore, our study provides further evidence for the contribution of BAFF/APRIL signaling to CLL biology, suggesting also that TACI detection might be useful in the selection of patients for novel targeting therapeutic approaches.

scholarly journals AB0024 IN VITRO CHARACTERIZATION OF CENERIMOD, A POTENT AND SELECTIVE SPHINGOSINE 1-PHOSPHATE RECEPTOR 1 (S1P1) MODULATOR IN PREVENTING MIGRATION OF NON-ACTIVATED AND ACTIVATED PRIMARY HUMAN B CELLS IN THE PRESENCE OR ABSENCE OF GLUCOCORTICOIDS

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1046.1-1046
Author(s):  
L. Schlicher ◽  
P. Kulig ◽  
M. Murphy ◽  
M. Keller
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Lymphocytes ◽  
Cell Activation ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
B Cell Activation ◽  
Human B Cells ◽  
Circulating Lymphocytes

Background:Cenerimod is a potent, selective, and orally active sphingosine 1-phosphate receptor 1 (S1P1) modulator that is currently being evaluated in a Phase 2b study in patients with systemic lupus erythematosus (SLE) (NCT03742037). S1P1 receptor modulators sequester circulating lymphocytes within lymph nodes, thereby reducing pathogenic autoimmune cells (including B lymphocytes) in the blood stream and in inflamed tissues. Extensive clinical experience has become available for the nonselective S1P receptor modulator fingolimod in relapsing forms of multiple sclerosis, supporting this therapeutic concept for the treatment of autoimmune disorders.Objectives:Although the effect of S1P-receptor modulators in reducing peripheral B cells is well documented1,2, the role of the S1P1 receptor on this cell type is only incompletely understood. In this study, the mode of action of cenerimod on primary human B cells was investigated in a series of in vitro experiments, including S1P1 receptor cell surface expression and chemotaxis towards S1P. Moreover, S1P1 expression following B cell activation in vitro was studied. As glucocorticoids (GC) are frequently used in the treatment of patients with autoimmune disorders including SLE, the potential influence of GC on the mode of action of cenerimod was evaluated.Methods:Primary human B lymphocytes from healthy donors were isolated from whole blood. In one set of experiments, cells were treated with different concentrations of cenerimod to measure S1P1 receptor internalization by flow cytometry. In a second set of experiments, isolated B cells were activated using different stimuli or left untreated. Cells were then analysed for S1P1 and CD69 cell surface expression and tested in a novel real-time S1P-mediated migration assay. In addition, the effect of physiological concentrations of GCs (prednisolone and prednisone) on cenerimod activity in preventing S1P mediated migration was tested.Results:In vitro, cenerimod led to a dose-dependent internalization of the S1P1 receptor on primary human B lymphocytes. Cenerimod also blocked migration of nonactivated and activated B lymphocytes towards S1P in a concentration-dependent manner, which is in line with the retention of lymphocytes in the lymph node and the reduction of circulating lymphocytes observed in the clinical setting. Upon B cell activation, which was monitored by CD69 upregulation, a simultaneous downregulation of S1P1 expression was detected, leading to less efficient S1P-directed cell migration. Importantly, physiological concentrations of GC did not affect the inhibitory activity of cenerimod on B cell migration.Conclusion:These results show that cenerimod, by modulating S1P1, blocks B lymphocyte migration towards its natural chemoattractant S1P and demonstrate compatibility of cenerimod with GC. These results are consistent with results of comparable experiments done previously using primary human T lymphocytes.References:[1]Nakamura M et al., Mult Scler. 2014 Sep; 20(10):1371-80.[2]Strasser DS et al., RMD Open 2020;6:e001261.Disclosure of Interests:None declared

scholarly journals Reduced peripheral blood regulatory B cell levels are not associated with the Expanded Disability Status Scale score in multiple sclerosis

2018 ◽  
Vol 46 (9) ◽  
pp. 3970-3978 ◽  
Author(s):  
Shujun Guo ◽  
Qingqing Chen ◽  
Xiaoli Liang ◽  
Mimi Mu ◽  
Jing He ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
B Cells ◽  
Peripheral Blood ◽  
Plasma Cells ◽  
Serum Levels ◽  
Memory B Cells ◽  
Healthy Controls ◽  
Expanded Disability Status Scale ◽  
Disability Status ◽  
Edss Score

Objective To investigate levels of regulatory B (Breg) cells, plasma cells, and memory B cells in the peripheral blood, and interleukin (IL)-10 in the serum of multiple sclerosis (MS) patients, and to determine the correlation between Breg cell levels and the Expanded Disability Status Scale (EDSS) score. Methods Levels of Breg cells, plasma cells, and memory B cells in the peripheral blood of 12 MS patients were measured using flow cytometry. IL-10 serum levels were measured by enzyme-linked immunosorbent assay. The correlation between Breg cell levels and MS EDSS score was measured using Pearson’s correlation coefficient. Results Compared with healthy controls, MS patients had decreased levels of CD19+CD24hiCD38hi Breg cells in their peripheral blood and reduced serum levels of IL-10; however, the ratios of CD19+CD27hiCD38hi plasma cells and CD19+CD27+CD24hi memory B cells to total B cells did not differ significantly between healthy controls and MS patients. CD19+CD24hiCD38hi Breg cell levels in the peripheral blood of MS patients were not significantly correlated with MS EDSS score. Conclusion Peripheral blood CD19+CD24hiCD38hi Breg cell levels and serum IL-10 levels were reduced in MS patients compared with controls, but Breg cell levels were not correlated with MS EDSS score.

scholarly journals Shortened platelet half-life in multiple myeloma

Blood ◽  
1986 ◽  
Vol 68 (2) ◽  
pp. 514-520
Author(s):  
E Fritz ◽  
H Ludwig ◽  
W Scheithauer ◽  
H Sinzinger
Keyword(s):  
Multiple Myeloma ◽  
Half Life ◽  
Serum Levels ◽  
Statistical Correlation ◽  
Control Group ◽  
Healthy Controls ◽  
Platelet Factor ◽  
Healthy Control

Various defects in platelet function have been reported as being associated with multiple myeloma. In 30 myeloma patients and 15 healthy controls, we investigated platelet survival using in vitro labeling of autologous platelets with 111indium-oxine and measuring the in vivo kinetics of the radioisotope. Significantly shortened platelet half- life in patients averaged 73 hours, while platelet half-life in the healthy controls averaged 107 hours. In myeloma patients, serum levels of thromboxane B2, beta-thromboglobulin, and platelet factor 4 were significantly elevated; aggregation indices were within the pathological range; platelet counts and spleen-liver indices, however, were comparable to those of the healthy control group. No statistical correlation was found between platelet half-life and paraprotein concentrations. Our findings suggest an initial--so far unexplained-- intravascular process of platelet activation and consumption that finally manifests in shortened platelet half-life. It seems that overt thrombocytopenia develops only when the compensatory capacity of the bone marrow finally becomes exhausted. Further studies should be able to elucidate the pathophysiologic processes involved.

scholarly journals Thrombopoietin in Patients With Congenital Thrombocytopenia and Absent Radii: Elevated Serum Levels, Normal Receptor Expression, But Defective Reactivity to Thrombopoietin

Blood ◽  
1997 ◽  
Vol 90 (2) ◽  
pp. 612-619 ◽  
Author(s):  
Matthias Ballmaier ◽  
Harald Schulze ◽  
Gabriele Strauβ ◽  
Klara Cherkaoui ◽  
Nicole Wittner ◽  
...  
Keyword(s):  
Elevated Serum ◽  
Signal Transduction Pathway ◽  
Adenosine Diphosphate ◽  
Serum Levels ◽  
Receptor Expression ◽  
Healthy Controls ◽  
Transduction Pathway ◽  
Platelet Response ◽  
Tar Syndrome

The pathophysiology of thrombocytopenia in the syndrome of thrombocytopenia with absent radii (TAR) is not yet understood. We examined thrombopoietin (TPO) serum levels and the in vitro reactivity of platelets to TPO in five patients affected with TAR syndrome. We found elevated TPO serum levels in all patients tested, excluding a TPO production defect as cause for thrombocytopenia in TAR syndrome. In addition, we found similar expression of the TPO receptor c-Mpl on the surface of platelets from TAR patients (5 of 5) and a similar molecular weight of the receptor as compared with healthy controls (4 of 4). Platelet response to adenosine diphosphate or thrombin receptor agonist peptide SFLLRN (TRAP) was normal in TAR patients. However, in contrast to results with healthy controls we could show absence of in vitro reactivity of platelets from TAR patients to recombinant TPO as measured by testing TPO synergism to adenine diphosphate and TRAP in platelet activation. TPO induced tyrosine phosphorylation of platelet proteins was completely absent (3 of 4) or markedly decreased (1 of 4). Our results indicate that defective megakaryocytopoiesis/thrombocytopoiesis in TAR syndrome is not caused by a defect in TPO production but a lack of response to TPO in the signal transduction pathway of c-Mpl.

scholarly journals Ascorbic acid attenuates activation and cytokine production in sepsis-like monocytes

2021 ◽  
Author(s):  
Tobias Schmidt ◽  
Robin Kahn ◽  
Fredrik Kahn
Keyword(s):  
Flow Cytometry ◽  
Ascorbic Acid ◽  
Cytokine Production ◽  
In Vitro Study ◽  
Surface Expression ◽  
High Dose ◽  
Functional Assay ◽  
Dependent Manner ◽  
Dose Dependent

Objective To investigate the effects of high dose ascorbic acid (AA) on monocyte polarization and cytokine production in vitro Design Experimental in vitro study of cells from healthy subjects and patients with sepsis Setting University research laboratory and academic hospital Subjects Six healthy controls and three patients with sepsis Interventions Monocytes were isolated from whole blood of healthy donors (n=6) and polarized in vitro for 48hrs using LPS or LTA. Polarization was confirmed by surface marker expression using flow cytometry. As a comparison, monocytes were also isolated from septic patients (n=3) and analyzed for polarization markers. The effect of AA on monocyte polarization was evaluated. As a functional assay, AA-treated monocytes were analyzed for cytokine production of TNF and IL-8 by intracellular staining and flow cytometry following activation with LPS or LTA. Measurements and Main Results Both LPS and LTA induced polarization in healthy monocytes in vitro, with increased expression of both pro- (CD40 and PDL1, p<0.05) and anti-inflammatory (CD16 and CD163, p<0.05) polarization markers, with non-significant effects on CD86 and CD206. This pattern resembled, at least partly, that of monocytes from septic patients. Treatment with AA significantly inhibited the upregulation of surface expression of CD16 and CD163 (p<0.05) in a dose dependent manner, but not CD40 or PDL-1. Finally, AA attenuated LPS or LTA-induced cytokine production of IL-8 and TNF in a dose-dependent manner (both p<0.05). Conclusions AA inhibits upregulation of anti-, but not pro-inflammatory related markers in LPS or LTA polarized monocytes. Additionally, AA attenuates cytokine production from in vitro polarized monocytes, displaying functional involvement. This study provides important insight into the immunological effects of high dose AA on monocytes, and potential implications in sepsis.

scholarly journals Carbohydrate-dependent B cell activation by fucose-binding bacterial lectins

2019 ◽  
Vol 12 (571) ◽  
pp. eaao7194 ◽  
Author(s):  
Isabel Wilhelm ◽  
Ella Levit-Zerdoun ◽  
Johanna Jakob ◽  
Sarah Villringer ◽  
Marco Frensch ◽  
...  
Keyword(s):  
B Cells ◽  
Cell Surface ◽  
B Cell ◽  
Cell Activation ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
B Cell Activation ◽  
Intracellular Ca ◽  
Bacterial Lectins

Bacterial lectins are typically multivalent and bind noncovalently to specific carbohydrates on host tissues to facilitate bacterial adhesion. Here, we analyzed the effects of two fucose-binding lectins, BambL fromBurkholderia ambifariaand LecB fromPseudomonas aeruginosa, on specific signaling pathways in B cells. We found that these bacterial lectins induced B cell activation, which, in vitro, was dependent on the cell surface expression of the B cell antigen receptor (BCR) and its co-receptor CD19, as well as on spleen tyrosine kinase (Syk) activity. The resulting release of intracellular Ca2+was followed by an increase in the cell surface abundance of the activation marker CD86, augmented cytokine secretion, and subsequent cell death, replicating all of the events that are observed in vitro upon canonical and antigen-mediated B cell activation. Moreover, injection of BambL in mice resulted in a substantial, BCR-independent loss of B cells in the bone marrow with simultaneous, transient enlargement of the spleen (splenomegaly), as well as an increase in the numbers of splenic B cells and myeloid cells. Together, these data suggest that bacterial lectins can initiate polyclonal activation of B cells through their sole capacity to bind to fucose.

scholarly journals Human macrophage inflammatory protein alpha (MIP-1 alpha) and MIP-1 beta chemokines attract distinct populations of lymphocytes.

1993 ◽  
Vol 177 (6) ◽  
pp. 1821-1826 ◽  
Author(s):  
T J Schall ◽  
K Bacon ◽  
R D Camp ◽  
J W Kaspari ◽  
D V Goeddel
Keyword(s):  
T Cells ◽  
B Cells ◽  
Cytotoxic T Cells ◽  
Human Macrophage ◽  
Immune Effector ◽  
Effector Cells ◽  
Inflammatory Protein ◽  
And Migration ◽  
Macrophage Inflammatory Protein

Lymphocyte trafficking is an essential process in immune and inflammatory functions which can be thought to contain at least two main components: adhesion and migration. Whereas adhesion molecules such as the selections are known to mediate the homing of leukocytes from the blood to the endothelium, the chemoattractant substances responsible for the migration of specific subsets of lymphocytes to sites of infection or inflammation are largely unknown. Here we show that two molecules in the chemokine (for chemoattractant cytokine) superfamily, human macrophage inflammatory protein 1 alpha (MIP-1 alpha) and MIP-1 beta, do not share identical attractant activities for lymphocyte subpopulations. When analyzed in vitro in microchemotaxis experiments, HuMIP-1 beta tends to attract CD4+ T lymphocytes, with some preference for T cells of the naive (CD45RA) phenotype. HuMIP-1 alpha, when tested in parallel with HuMIP-1 beta, is a more potent lymphocyte chemoattractant with a broader range of concentration-dependent chemoattractant specificities. HuMIP-1 alpha at a concentration of 100 pg/ml attracts B cells and cytotoxic T cells, whereas at higher concentrations (10 ng/ml), the migration of these cells appears diminished, and the migration of CD4+ T cells is enhanced. Thus, in this assay system, HuMIP-1 alpha and -1 beta have differential attractant activities for subsets of immune effector cells, with HuMIP-1 alpha having greater effects than HuMIP-1 beta, particularly on B cells.

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