The effect of combination antiretroviral therapy on CD5 B- cells, B-cell activation and hypergammaglobulinaemia in HIV-1-infected patients

HIV-1 Envelope (Env) proteins designed to induce neutralizing antibody responses allow study of the role of affinities (equilibrium dissociation constant, KD) and kinetic rates (association/dissociation rates) on B cell antigen recognition. It is unclear whether affinity discrimination during B cell activation is based solely on Env protein binding KD, and whether B cells discriminate between proteins of similar affinities but that bind with different kinetic rates. Here we used a panel of Env proteins and Ramos B cell lines expressing IgM BCRs with specificity for CD4 binding-site broadly neutralizing (bnAb) or a precursor antibody to study the role of antigen binding kinetic rates on both early (proximal/distal signaling) and late events (BCR/antigen internalization) in B cell activation. Our results support a kinetic model for B cell activation in which Env protein affinity discrimination is based not on overall KD, but on sensing of association rate and a threshold antigen-BCR half-life.

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Hyaluronate-CD44 Interactions Can Induce Murine B-Cell Activation

Blood ◽

10.1182/blood.v89.8.2901 ◽

1997 ◽

Vol 89 (8) ◽

pp. 2901-2908 ◽

Cited By ~ 71

Author(s):

Asimah Rafi ◽

Mitzi Nagarkatti ◽

Prakash S. Nagarkatti

Keyword(s):

T Cells ◽

B Cells ◽

B Cell ◽

Cell Activation ◽

Critical Role ◽

Surface Glycoprotein ◽

B Cell Differentiation ◽

B Cell Activation ◽

Cell Surface Glycoprotein ◽

Immunodeficient Mice

Abstract CD44 is a widely distributed cell surface glycoprotein whose principal ligand has been identified as hyaluronic acid (HA), a major component of the extracellular matrix (ECM). Recent studies have demonstrated that activation through CD44 leads to induction of effector function in T cells and macrophages. In the current study, we investigated whether HA or monoclonal antibodies (MoAbs) against CD44 would induce a proliferative response in mouse lymphocytes. Spleen cells from normal and nude, but not severe combined immunodeficient mice, exhibited strong proliferative responsiveness to stimulation with soluble HA or anti-CD44 MoAbs. Furthermore, purified B cells, but not T cells, were found to respond to HA. HA was unable to stimulate T cells even in the presence of antigen presenting cells (APC) and was unable to act as a costimulus in the presence of mitogenic or submitogenic concentrations of anti-CD3 MoAbs. In contrast, stimulation of B cells with HA in vitro, led to B-cell differentiation as measured by production of IgM antibodies in addition to increased expression of CD44 and decreased levels of CD45R. The fact that the B cells were responding directly to HA through its binding to CD44 and not to any contaminants or endotoxins was demonstrated by the fact that F(ab)2 fragments of anti-CD44 MoAbs or soluble CD44 fusion proteins could significantly inhibit the HA-induced proliferation of B cells. Also, HA-induced proliferation of B cells was not affected by the addition of polymixin B, and B cells from lipopolysaccharide (LPS)-unresponsive C3H/HeJ strain responded strongly to stimulation with HA. Furthermore, HA, but not chondroitin-sulfate, another major component of the ECM, induced B-cell activation. It was also noted that injection of HA intraperitoneally, triggered splenic B cell proliferation in vivo. Together, the current study demonstrates that interaction between HA and CD44 can regulate murine B-cell effector functions and that such interactions may play a critical role during normal or autoimmune responsiveness of B cells.

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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

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.2482 ◽

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

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702 Dual blockade of the PD-1 checkpoint pathway and the adenosinergic negative feedback signaling pathway with a PD-1/CD73 bispecific antibody for cancer immune therapy

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0702 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A744-A744

Author(s):

Tingting Zhong ◽

Zhaoliang Huang ◽

Xinghua Pang ◽

Na Chen ◽

Xiaoping Jin ◽

...

Keyword(s):

T Cell ◽

B Cells ◽

B Cell ◽

T Cell Activation ◽

Negative Feedback ◽

Immune Suppression ◽

Specific Antibody ◽

Cell Activation ◽

Immune Therapy ◽

B Cell Activation

BackgroundCD73 (ecto-5’-nucleotidase) is an ecto-nucleotidase that dephosphorylate AMP to form adenosine. Activation of adenosine signaling pathway in immune cells leads to the suppression of effector functions, down-regulate macrophage phagocytosis, inhibit pro-inflammatory cytokine release, as well as yield aberrantly differentiated dendritic cells producing pro-tumorigenic molecules.1 In the tumor microenvironment, adenosinergic negative feedback signaling facilitated immune suppression is considered an important mechanism for immune evasion of cancer cells.2 3 Combination of CD73 and anti-PD-1 antibody has shown promising activity in suppressing tumor growth. Hence, we developed AK119, an anti- human CD73 monoclonal antibody, and AK123,a bi-specific antibody targeting both PD-1 and CD73 for immune therapy of cancer.MethodsAK119 is a humanized antibody against CD73 and AK123 is a tetrameric bi-specific antibody targeting PD-1 and CD73. Binding assays of AK119 and AK123 to antigens, and antigen expressing cells were performed by using ELISA, Fortebio, and FACS assays. In-vitro assays to investigate the activity of AK119 and AK123 to inhibit CD73 enzymatic activity in modified CellTiter-Glo assay, to induce endocytosis of CD73, and to activate B cells were performed. Assay to evaluate AK123 activity on T cell activation were additionally performed. Moreover, the activities of AK119 and AK123 to mediate ADCC, CDC in CD73 expressing cells were also evaluated.ResultsAK119 and AK123 could bind to its respective soluble or membrane antigens expressing on PBMCs, MDA-MB-231, and U87-MG cells with high affinity. Results from cell-based assays indicated that AK119 and AK123 effectively inhibited nucleotidase enzyme activity of CD73, mediated endocytosis of CD73, and induced B cell activation by upregulating CD69 and CD83 expression on B cells, and showed more robust CD73 blocking and B cell activation activities compared to leading clinical candidate targeting CD73. AK123 could also block PD-1/PD-L1 interaction and enhance T cell activation.ConclusionsIn summary, AK119 and AK123 represent good preclinical biological properties, which support its further development as an anti-cancer immunotherapy or treating other diseases.ReferencesDeaglio S, Dwyer KM, Gao W, Friedman D, Usheva A, Erat A, Chen JF, Enjyoji K, Linden J, Oukka M, et al. Adenosine generation catalyzed by CD39 and CD73 expressed on regulatory T cells mediates immune suppression. J Exp Med 2007; 204:1257–65.Huang S, Apasov S, Koshiba M, Sitkovsky M. Role of A2a extracellular adenosine receptor-mediated signaling in adenosine-mediated inhibition of T-cell activation and expansion. Blood. 1997; 90:1600–10.Novitskiy SV, Ryzhov S, Zaynagetdinov R, Goldstein AE, Huang Y, Tikhomirov OY, Blackburn MR, Biaggioni I,Carbone DP, Feoktistov I, et al. Adenosine receptors in regulation of dendritic cell differentiation and function. Blood 2008; 112:1822–31.

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Association of interleukin-10 promoter genetic variants with T-cell and B-cell activation in HIV-1 infection

Retrovirology ◽

10.1186/1742-4690-9-s2-p168 ◽

2012 ◽

Vol 9 (S2) ◽

Author(s):

D Naicker ◽

B Julg ◽

C McClurg ◽

M Ghebremichael ◽

F Porichis ◽

...

Keyword(s):

T Cell ◽

B Cell ◽

Genetic Variants ◽

Cell Activation ◽

Interleukin 10 ◽

B Cell Activation ◽

Hiv 1

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Deep Phenotyping of CD11c+ B Cells in Systemic Autoimmunity and Controls

Frontiers in Immunology ◽

10.3389/fimmu.2021.635615 ◽

2021 ◽

Vol 12 ◽

Author(s):

Hector Rincon-Arevalo ◽

Annika Wiedemann ◽

Ana-Luisa Stefanski ◽

Marie Lettau ◽

Franziska Szelinski ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Lupus Erythematosus ◽

Cell Activation ◽

B Cell Activation ◽

Membrane Expression ◽

Ki 67 ◽

Inflammatory Conditions ◽

Systemic Autoimmunity ◽

Enhanced Expression

Circulating CD11c+ B cells are a key phenomenon in certain types of autoimmunity but have also been described in the context of regular immune responses (i.e., infections, vaccination). Using mass cytometry to profile 46 different markers on individual immune cells, we systematically initially confirmed the presence of increased CD11c+ B cells in the blood of systemic lupus erythematosus (SLE) patients. Notably, significant differences in the expression of CD21, CD27, and CD38 became apparent between CD11c− and CD11c+ B cells. We observed direct correlation of the frequency of CD21−CD27− B cells and CD21−CD38− B cells with CD11c+ B cells, which were most pronounced in SLE compared to primary Sjögren's syndrome patients (pSS) and healthy donors (HD). Thus, CD11c+ B cells resided mainly within memory subsets and were enriched in CD27−IgD−, CD21−CD27−, and CD21−CD38− B cell phenotypes. CD11c+ B cells from all donor groups (SLE, pSS, and HD) showed enhanced CD69, Ki-67, CD45RO, CD45RA, and CD19 expression, whereas the membrane expression of CXCR5 and CD21 were diminished. Notably, SLE CD11c+ B cells showed enhanced expression of the checkpoint molecules CD86, PD1, PDL1, CD137, VISTA, and CTLA-4 compared to HD. The substantial increase of CD11c+ B cells with a CD21− phenotype co-expressing distinct activation and checkpoint markers, points to a quantitative increased alternate (extrafollicular) B cell activation route possibly related to abnormal immune regulation as seen under the striking inflammatory conditions of SLE which shows a characteristic PD-1/PD-L1 upregulation.

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Antiviral Protection and Germinal Center Formation, But Impaired B Cell Memory in the Absence of CD19

Journal of Experimental Medicine ◽

10.1084/jem.188.1.145 ◽

1998 ◽

Vol 188 (1) ◽

pp. 145-155 ◽

Cited By ~ 49

Author(s):

Thomas Fehr ◽

Robert C. Rickert ◽

Bernhard Odermatt ◽

Jürgen Roes ◽

Klaus Rajewsky ◽

...

Keyword(s):

T Cell ◽

B Cells ◽

B Cell ◽

Cell Activation ◽

Antibody Responses ◽

B Cell Activation ◽

Protein Antigens ◽

Cell Memory ◽

B Cell Memory

Coligation of CD19, a molecule expressed during all stages of B cell development except plasmacytes, lowers the threshold for B cell activation with anti-IgM by a factor of 100. The cytoplasmic tail of CD19 contains nine tyrosine residues as possible phosphorylation sites and is postulated to function as the signal transducing element for complement receptor (CR)2. Generation and analysis of CD19 gene–targeted mice revealed that T cell–dependent (TD) antibody responses to proteinaceous antigens were impaired, whereas those to T cell–independent (TI) type 2 antigens were normal or even augmented. These results are compatible with earlier complement depletion studies and the postulated function of CD19. To analyze the role of CD19 in antiviral antibody responses, we immunized CD19−/− mice with viral antigens of TI-1, TI-2, and TD type. The effect of CD19 on TI responses was more dependent on antigen dose and replicative capacity than on antigen type. CR blocking experiments confirmed the role of CD19 as B cell signal transducer for complement. In contrast to immunization with protein antigens, infection of CD19−/− mice with replicating virus led to generation of specific germinal centers, which persisted for >100 d, whereas maintenance of memory antibody titers as well as circulating memory B cells was fully dependent on CD19. Thus, our study confirms a costimulatory role of CD19 on B cells under limiting antigen conditions and indicates an important role for B cell memory.

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Antigen Extraction and B Cell Activation Enable Identification of Rare Membrane Antigen Specific Human B Cells

Frontiers in Immunology ◽

10.3389/fimmu.2019.00829 ◽

2019 ◽

Vol 10 ◽

Cited By ~ 3

Author(s):

Maria Zimmermann ◽

Natalie Rose ◽

John M. Lindner ◽

Hyein Kim ◽

Ana Rita Gonçalves ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Cell Activation ◽

B Cell Activation ◽

Human B Cells

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Requirement for memory B-cell activation in protection from heterologous influenza virus reinfection

International Immunology ◽

10.1093/intimm/dxz049 ◽

2019 ◽

Vol 31 (12) ◽

pp. 771-779 ◽

Cited By ~ 8

Author(s):

Sarah Leach ◽

Ryo Shinnakasu ◽

Yu Adachi ◽

Masatoshi Momota ◽

Chieko Makino-Okamura ◽

...

Keyword(s):

Influenza Virus ◽

B Cells ◽

B Cell ◽

Cell Activation ◽

Influenza Infection ◽

Memory B Cells ◽

B Cell Activation ◽

Memory B Cell

Memory B cells protect against heterologous influenza infection

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The KDM4A/KDM4C/NF-κB and WDR5 epigenetic cascade regulates the activation of B cells

Nucleic Acids Research ◽

10.1093/nar/gky281 ◽

2018 ◽

Vol 46 (11) ◽

pp. 5547-5560 ◽

Cited By ~ 9

Author(s):

Kuo-Hsuan Hung ◽

Yong H Woo ◽

I-Ying Lin ◽

Chin-Hsiu Liu ◽

Li-Chieh Wang ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Lupus Erythematosus ◽

Cell Activation ◽

De Novo ◽

Epigenetic Mechanism ◽

B Cell Activation ◽

Motif Analysis ◽

Follicular Helper

Abstract T follicular helper (Tfh) cell-derived signals promote activation and proliferation of antigen-primed B cells. It remains unclear whether epigenetic regulation is involved in the B cell responses to Tfh cell-derived signals. Here, we demonstrate that Tfh cell-mimicking signals induce the expression of histone demethylases KDM4A and KDM4C, and the concomitant global down-regulation of their substrates, H3K9me3/me2, in B cells. Depletion of KDM4A and KDM4C potentiates B cell activation and proliferation in response to Tfh cell-derived signals. ChIP-seq and de novo motif analysis reveals NF-κB p65 as a binding partner of KDM4A and KDM4C. Their co-targeting to Wdr5, a MLL complex member promoting H3K4 methylation, up-regulates cell cycle inhibitors Cdkn2c and Cdkn3. Thus, Tfh cell-derived signals trigger KDM4A/KDM4C - WDR5 - Cdkn2c/Cdkn3 cascade in vitro, an epigenetic mechanism regulating proper proliferation of activated B cells. This pathway is dysregulated in B cells from systemic lupus erythematosus patients and may represent a pathological link.

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