scholarly journals Memory B Cells in Multiple Sclerosis: Emerging Players in Disease Pathogenesis

2021 ◽  
Vol 12 ◽  
Author(s):  
Krista D. DiSano ◽  
Francesca Gilli ◽  
Andrew R. Pachner
Keyword(s):  
Multiple Sclerosis ◽  
B Cells ◽  
B Cell ◽  
Antigen Presentation ◽  
Cytokine Production ◽  
Memory B Cells ◽  
Cell Phenotype ◽  
Effector Functions ◽  
Immunomodulatory Therapies ◽  
Antibody Secreting Cells

Multiple Sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. Once thought to be primarily driven by T cells, B cells are emerging as central players in MS immunopathogenesis. Interest in multiple B cell phenotypes in MS expanded following the efficacy of B cell-depleting agents targeting CD20 in relapsing-remitting MS and inflammatory primary progressive MS patients. Interestingly, these therapies primarily target non-antibody secreting cells. Emerging studies seek to explore B cell functions beyond antibody-mediated roles, including cytokine production, antigen presentation, and ectopic follicle-like aggregate formation. Importantly, memory B cells (Bmem) are rising as a key B cell phenotype to investigate in MS due to their antigen-experience, increased lifespan, and rapid response to stimulation. Bmem display diverse effector functions including cytokine production, antigen presentation, and serving as antigen-experienced precursors to antibody-secreting cells. In this review, we explore the cellular and molecular processes involved in Bmem development, Bmem phenotypes, and effector functions. We then examine how these concepts may be applied to the potential role(s) of Bmem in MS pathogenesis. We investigate Bmem both within the periphery and inside the CNS compartment, focusing on Bmem phenotypes and proposed functions in MS and its animal models. Finally, we review how current immunomodulatory therapies, including B cell-directed therapies and other immunomodulatory therapies, modify Bmem and how this knowledge may be harnessed to direct therapeutic strategies in MS.

scholarly journals A pathogenic and clonally expanded B cell transcriptome in active multiple sclerosis

2020 ◽  
Vol 117 (37) ◽  
pp. 22932-22943 ◽  
Author(s):  
Akshaya Ramesh ◽  
Ryan D. Schubert ◽  
Ariele L. Greenfield ◽  
Ravi Dandekar ◽  
Rita Loudermilk ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
B Cells ◽  
B Cell ◽  
Single Cell ◽  
Rna Sequencing ◽  
Chemokine Receptors ◽  
Plasma Cells ◽  
Cholesterol Biosynthesis ◽  
Memory B Cells ◽  
Cell Phenotype

Central nervous system B cells have several potential roles in multiple sclerosis (MS): secretors of proinflammatory cytokines and chemokines, presenters of autoantigens to T cells, producers of pathogenic antibodies, and reservoirs for viruses that trigger demyelination. To interrogate these roles, single-cell RNA sequencing (scRNA-Seq) was performed on paired cerebrospinal fluid (CSF) and blood from subjects with relapsing-remitting MS (RRMS; n = 12), other neurologic diseases (ONDs; n = 1), and healthy controls (HCs; n = 3). Single-cell immunoglobulin sequencing (scIg-Seq) was performed on a subset of these subjects and additional RRMS (n = 4), clinically isolated syndrome (n = 2), and OND (n = 2) subjects. Further, paired CSF and blood B cell subsets (RRMS; n = 7) were isolated using fluorescence activated cell sorting for bulk RNA sequencing (RNA-Seq). Independent analyses across technologies demonstrated that nuclear factor kappa B (NF-κB) and cholesterol biosynthesis pathways were activated, and specific cytokine and chemokine receptors were up-regulated in CSF memory B cells. Further, SMAD/TGF-β1 signaling was down-regulated in CSF plasmablasts/plasma cells. Clonally expanded, somatically hypermutated IgM+ and IgG1+ CSF B cells were associated with inflammation, blood–brain barrier breakdown, and intrathecal Ig synthesis. While we identified memory B cells and plasmablast/plasma cells with highly similar Ig heavy-chain sequences across MS subjects, similarities were also identified with ONDs and HCs. No viral transcripts, including from Epstein–Barr virus, were detected. Our findings support the hypothesis that in MS, CSF B cells are driven to an inflammatory and clonally expanded memory and plasmablast/plasma cell phenotype.

scholarly journals Ectopic Lymphoid Follicles in Multiple Sclerosis: Centers for Disease Control?

2020 ◽  
Vol 11 ◽  
Author(s):  
Austin Negron ◽  
Olaf Stüve ◽  
Thomas G. Forsthuber
Keyword(s):  
Multiple Sclerosis ◽  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
T Cell Responses ◽  
Memory B Cells ◽  
Lymphoid Follicles ◽  
Cell Responses ◽  
B Cell Responses

While the contribution of autoreactive CD4+ T cells to the pathogenesis of Multiple Sclerosis (MS) is widely accepted, the advent of B cell-depleting monoclonal antibody (mAb) therapies has shed new light on the complex cellular mechanisms underlying MS pathogenesis. Evidence supports the involvement of B cells in both antibody-dependent and -independent capacities. T cell-dependent B cell responses originate and take shape in germinal centers (GCs), specialized microenvironments that regulate B cell activation and subsequent differentiation into antibody-secreting cells (ASCs) or memory B cells, a process for which CD4+ T cells, namely follicular T helper (TFH) cells, are indispensable. ASCs carry out their effector function primarily via secreted Ig but also through the secretion of both pro- and anti-inflammatory cytokines. Memory B cells, in addition to being capable of rapidly differentiating into ASCs, can function as potent antigen-presenting cells (APCs) to cognate memory CD4+ T cells. Aberrant B cell responses are prevented, at least in part, by follicular regulatory T (TFR) cells, which are key suppressors of GC-derived autoreactive B cell responses through the expression of inhibitory receptors and cytokines, such as CTLA4 and IL-10, respectively. Therefore, GCs represent a critical site of peripheral B cell tolerance, and their dysregulation has been implicated in the pathogenesis of several autoimmune diseases. In MS patients, the presence of GC-like leptomeningeal ectopic lymphoid follicles (eLFs) has prompted their investigation as potential sources of pathogenic B and T cell responses. This hypothesis is supported by elevated levels of CXCL13 and circulating TFH cells in the cerebrospinal fluid (CSF) of MS patients, both of which are required to initiate and maintain GC reactions. Additionally, eLFs in post-mortem MS patient samples are notably devoid of TFR cells. The ability of GCs to generate and perpetuate, but also regulate autoreactive B and T cell responses driving MS pathology makes them an attractive target for therapeutic intervention. In this review, we will summarize the evidence from both humans and animal models supporting B cells as drivers of MS, the role of GC-like eLFs in the pathogenesis of MS, and mechanisms controlling GC-derived autoreactive B cell responses in MS.

scholarly journals Memory persistence and differentiation into antibody-secreting cells accompanied by positive selection in longitudinal BCR repertoires

2022 ◽  
Author(s):  
Artem I. Mikelov ◽  
Evgeniia I. Alekseeva ◽  
Ekaterina A. Komech ◽  
Dmitriy B. Staroverov ◽  
Maria A. Turchaninova ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
Plasma Cells ◽  
Inflammatory Diseases ◽  
Affinity Maturation ◽  
Memory B Cells ◽  
Immune Memory ◽  
Memory B Cell ◽  
Antibody Secreting Cells

B-cell mediated immune memory holds both plasticity and conservatism to respond to new challenges and repeated infections. Here, we analyze the dynamics of immunoglobulin heavy chain (IGH) repertoires of memory B cells, plasmablasts and plasma cells sampled several times during one year from peripheral blood of volunteers without severe inflammatory diseases. We reveal a high degree of clonal persistence in individual memory B-cell subsets with inter-individual convergence in memory and antibody-secreting cells (ASCs). Clonotypes in ASCs demonstrate clonal relatedness to memory B cells and are transient in peripheral blood. Two clusters of expanded clonal lineages displayed different prevalence of memory B cells, isotypes, and persistence. Phylogenetic analysis revealed signs of reactivation of persisting memory B cell-enriched clonal lineages, accompanied by new rounds of affinity maturation during proliferation to ASCs. Negative selection contributes to both, persisting and reactivated lineages, saving functionality and specificity of BCRs to protect from the current and future pathogens.

scholarly journals Cytoplasmic FOXO1 identifies a novel disease-activity associated B cell phenotype in SLE

2018 ◽  
Vol 5 (1) ◽  
pp. e000296 ◽  
Author(s):  
Molly K Hritzo Ahye ◽  
Amit Golding
Keyword(s):  
B Cells ◽  
Disease Activity ◽  
B Cell ◽  
Lupus Erythematosus ◽  
Cell Activation ◽  
Activity Index ◽  
Human Lymphocytes ◽  
Disease Activity Index ◽  
Memory B Cells ◽  
Cell Phenotype

Systemic lupus erythematosus (SLE) is a manifestation of hyperactivated lymphocytes and results, in part, from the loss of normal tolerance checkpoints. FOXO1 is a transcription factor involved at critical early and late B cell development checkpoints; however, its role in regulating peripheral B cell tolerance is not fully understood. We have applied our published approach for using imaging flow cytometry to study native FOXO1 localisation in human lymphocytes to peripheral blood samples from healthy individuals versus patients with SLE. We report, here, on dramatic cytoplasmic localisation of FOXO1 in two peripheral B cell SLE subsets: IgD-CD27+ (class-switched memory) B cells and IgD-CD27- (atypical memory) B cells. The latter, so-called ‘Double Negative’ (DN) B cells have previously been shown to be increased in SLE and enriched in autoreactive clones. Cytoplasmic-predominant FOXO1 (CytoFOX) B cells are significantly increased in patients with SLE as compared to healthy controls, and the levels of CytoFoOX DN B cells correlate directly with SLE disease activity. The highest abundance of CytoFox DN B cells was observed in African American females with SLE Disease Activity Index (SLEDAI)≥6. The phenotype of CytoFOX DN B cells in SLE includes uniquely low CD20 expression and high granularity/side scatter. As FOXO1 phosphorylation downstream of B cell receptor-dependent signalling is required for nuclear exclusion, CytoFOX B cells likely represent a high state of B cell activation with excess signalling and/or loss of phosphatase activity. We hypothesise that CytoFOX B cells in lupus represent a novel biomarker for the expansion of pathological, autoreactive B cells which may provide new insights into the pathophysiology of SLE.

Deletion or Inhibition of Fc Gamma Receptor IIb (CD32) Prevents the Memory B Cell Response to Factor VIII in a Hemophilia A Mouse Model

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 204-204 ◽  
Author(s):  
Sonja Werwitzke ◽  
Marcus von Hornung ◽  
Katy Kalippke ◽  
Arne Trummer ◽  
Arnold Ganser ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Knockout Mice ◽  
Cell Response ◽  
Hemophilia A ◽  
Memory B Cells ◽  
Double Knockout ◽  
Memory B Cell ◽  
Specific Memory ◽  
Antibody Secreting Cells

Abstract Abstract 204 The formation of inhibitory antibodies to factor VIII (FVIII) is the foremost complication of replacement therapy in hemophilia A. Patients with inhibitors are treated with very high doses of FVIII, over prolonged periods of time, to induce immune tolerance. Studies in a hemophilia A mouse model demonstrated that very high doses of FVIII can induce apoptosis in FVIII-specific memory B cells and prevent their differentiation into antibody-secreting cells. The Fc gamma receptor IIb (FcgRIIb) is expressed on B cells and mediates inhibitory signals after crosslinking with the B cell receptor. Here, we studied the potential role of this receptor in the regulation of memory B cell response to FVIII. FVIII knockout mice (B6;129S4-F8tm2Kaz/J) were crossed with FcgRIIb knockout mice (B6;129S4-Fcgr2btm1Ttk/J). Comparing F8−/− mice and F8−/−/FcgR2b−/− double knockout mice, the initial anti-FVIII antibody formation was similar after intravenous exposure to 4 weekly doses of 80 or 400 IU/kg. Similar numbers of FVIII-specific antibody-secreting cells were detected in the spleen and bone marrow by ELISPOT. As previously shown, in vitro re-stimulation of memory B cells from spleens of immunized F8−/− mice at doses of 1 to 200 ng/ml induced their differentiation into antibody-secreting cells. Higher doses of 400 to 800 ng/ml prevented differentiation. In F8−/−/FcgR2b−/− double knockout mice, however, formation of antibody-secreting cells was completely inhibited across all FVIII doses tested. Addition of B220-depleted splenocytes from F8−/− mice did not restore memory B cell function in F8−/−/FcgR2b−/− double knockout mice, indicating that the observed effect was not due to dysfunction of follicular dendritic cells or other antigen-presenting cells. Inhibition of FcgRIIb using a monoclonal antibody prevented the FVIII-specific memory B cell response in splenocytes from immunized F8−/− mice. Staining with propidium iodide, annexin V, or anti-caspase 3 indicated increased rates of apoptosis when FcgRIIb was blocked during re-stimulation. In summary, FcgRIIb plays a crucial role for the differentiation of FVIII-specific splenic memory B cells into antibody-secreting cells. Inhibition of FcgRIIb appears to sensitize B cells for apoptosis during re-stimulation with FVIII. This mechanism could potentially facilitate the eradication of FVIII-specific memory B cells during ITI. Disclosures: No relevant conflicts of interest to declare.

IgM+ memory B cells induced in response to Plasmodium berghei adopt a germinal centre B cell phenotype during secondary infection

Parasitology ◽  
2020 ◽  
Vol 147 (9) ◽  
pp. 994-998 ◽  
Author(s):  
Halina M. Pietrzak ◽  
Lisa J. Ioannidis ◽  
Diana S. Hansen
Keyword(s):  
B Cells ◽  
B Cell ◽  
Plasma Cells ◽  
Secondary Infection ◽  
Memory B Cells ◽  
Germinal Centre ◽  
Cell Phenotype ◽  
Memory B Cell ◽  
Humoral Immune ◽  
Transfer Strategies

AbstractEmerging evidence started to delineate multiple layers of memory B cells, with distinct effector functions during recall responses. Whereas most studies examining long-lived memory B cell responses have focussed on the IgG+ memory B cell compartment, IgM+ memory B cells have only recently started to receive attention. It has been proposed that unlike IgG+ memory B cells, which differentiate into antibody-secreting plasma cells upon antigen re-encounter, IgM+ memory B cells might have the additional capacity to establish secondary germinal centre (GC) responses. The precise function of IgM+ memory B cells in the humoral immune response to malaria has not been fully defined. Using a murine model of severe malaria infection and adoptive transfer strategies we found that IgM+ memory B cells induced in responses to P. berghei ANKA readily proliferate upon re-infection and adopt a GC B cell-like phenotype. The results suggest that that IgM+ memory B cells might play an important role in populating secondary GCs after re-infection with Plasmodium, thereby initiating the induction of B cell clones with enhanced affinity for antigen, at faster rates than naive B cells.

scholarly journals Differential effects of fingolimod on B-cell populations in multiple sclerosis

2014 ◽  
Vol 20 (10) ◽  
pp. 1371-1380 ◽  
Author(s):  
Masakazu Nakamura ◽  
Takako Matsuoka ◽  
Norio Chihara ◽  
Sachiko Miyake ◽  
Wakiro Sato ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
B Cells ◽  
B Cell ◽  
Mononuclear Cells ◽  
Memory B Cells ◽  
Lymphoid Cells ◽  
Oral Drug ◽  
Cell Populations ◽  
Lymphoid Tissues ◽  
Ki 67

Background: Fingolimod is an oral drug approved for multiple sclerosis (MS) with an ability to trap central memory T cells in secondary lymphoid tissues; however, its variable effectiveness in individual patients indicates the need to evaluate its effects on other lymphoid cells. Objective: To clarify the effects of fingolimod on B-cell populations in patients with MS. Methods: We analysed blood samples from 9 fingolimod-treated and 19 control patients with MS by flow cytometry, to determine the frequencies and activation states of naive B cells, memory B cells, and plasmablasts. Results: The frequencies of each B-cell population in peripheral blood mononuclear cells (PBMC) were greatly reduced 2 weeks after starting fingolimod treatment. Detailed analysis revealed a significant reduction in activated memory B cells (CD38int-high), particularly those expressing Ki-67, a marker of cell proliferation. Also, we noted an increased proportion of activated plasmablasts (CD138+) among whole plasmablasts, in the patients treated with fingolimod. Conclusions: The marked reduction of Ki-67+ memory B cells may be directly linked with the effectiveness of fingolimod in treating MS. In contrast, the relative resistance of CD138+ plasmablasts to fingolimod may be of relevance for understanding the differential effectiveness of fingolimod in individual patients.

scholarly journals The Choroid Plexus Is Permissive for a Preactivated Antigen-Experienced Memory B-Cell Subset in Multiple Sclerosis

2021 ◽  
Vol 11 ◽  
Author(s):  
Jürgen Haas ◽  
Henriette Rudolph ◽  
Leonardo Costa ◽  
Simon Faller ◽  
Saskia Libicher ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
B Cells ◽  
B Cell ◽  
Choroid Plexus ◽  
Cell Activation ◽  
Choroid Plexus Papilloma ◽  
Cell Subset ◽  
Memory B Cells ◽  
Cell Trafficking ◽  
Migration Routes

The role of B cells in multiple sclerosis (MS) is increasingly recognized. B cells undergo compartmentalized redistribution in blood and cerebrospinal fluid (CSF) during active MS, whereby memory B cells accumulate in the CSF. While B-cell trafficking across the blood–brain barrier has been intensely investigated, cellular diapedesis through the blood–CSF barrier (BCSFB) is incompletely understood. To investigate how B cells interact with the choroid plexus to transmigrate into the CSF we isolated circulating B cells from healthy donors (HC) and MS patients, utilized an inverted cell culture filter system of human choroid plexus papilloma (HIBCPP) cells to determine transmigration rates of B-cell subsets, immunofluorescence, and electron microscopy to analyze migration routes, and qRT-PCR to determine cytokines/chemokines mediating B-cell diapedesis. We also screened the transcriptome of intrathecal B cells from MS patients. We found, that spontaneous transmigration of HC- and MS-derived B cells was scant, yet increased significantly in response to B-cell specific chemokines CXCL-12/CXCL-13, was further boosted upon pre-activation and occurred via paracellular and transcellular pathways. Migrating cells exhibited upregulation of several genes involved in B-cell activation/migration and enhanced expression of chemokine receptors CXCR4/CXCR5, and were predominantly of isotype class switched memory phenotype. This antigen-experienced migratory subset displayed more pronounced chemotactic activities in MS than in HC and was retrieved in intrathecal B cells from patients with active MS. Trafficking of class-switched memory B cells was downscaled in a small cohort of natalizumab-exposed MS patients and the proportions of these phenotypes were reduced in peripheral blood yet were enriched intrathecally in patients who experienced recurrence of disease activity after withdrawal of natalizumab. Our findings highlight the relevance of the BCSFB as important gate for the entry of potentially harmful activated B cells into the CSF.

scholarly journals Characterising the Phenotypic Diversity of Antigen-Specific Memory B Cells Before and After Vaccination

2021 ◽  
Vol 12 ◽  
Author(s):  
M. Christian Tjiam ◽  
Sonia Fernandez ◽  
Martyn A. French
Keyword(s):  
B Cells ◽  
B Cell ◽  
Phenotypic Diversity ◽  
Binding Capacity ◽  
Booster Vaccination ◽  
Cell Receptor ◽  
Memory B Cells ◽  
Cell Phenotype ◽  
Antigen Binding ◽  
B Cell Subsets

The diversity of B cell subsets and their contribution to vaccine-induced immunity in humans are not well elucidated but hold important implications for rational vaccine design. Prior studies demonstrate that B cell subsets distinguished by immunoglobulin (Ig) isotype expression exhibit divergent activation-induced fates. Here, the antigen-specific B cell response to tetanus toxoid (TTd) booster vaccination was examined in healthy adults, using a dual-TTd tetramer staining flow cytometry protocol. Unsupervised analyses of the data revealed that prior to vaccination, IgM-expressing CD27+ B cells accounted for the majority of TTd-binding B cells. 7 days following vaccination, there was an acute expansion of TTd-binding plasmablasts (PB) predominantly expressing IgG, and a minority expressing IgA or IgM. Frequencies of all PB subsets returned to baseline at days 14 and 21. TTd-binding IgG+ and IgA+ memory B cells (MBC) exhibited a steady and delayed maximal expansion compared to PB, peaking in frequencies at day 14. In contrast, the number of TTd-binding IgM+IgD+CD27+ B cells and IgM-only CD27+ B cells remain unchanged following vaccination. To examine TTd-binding capacity of IgG+ MBC and IgM+IgD+CD27+ B cells, surface TTd-tetramer was normalised to expression of the B cell receptor-associated CD79b subunit. CD79b-normalised TTd binding increased in IgG+ MBC, but remained unchanged in IgM+IgD+CD27+ B cells, and correlated with the functional affinity index of plasma TTd-specific IgG antibodies, following vaccination. Finally, frequencies of activated (PD-1+ICOS+) circulating follicular helper T cells (cTFH), particularly of the CXCR3-CCR6- cTFH2 cell phenotype, at their peak expansion, strongly predicted antigen-binding capacity of IgG+ MBC. These data highlight the phenotypic and functional diversity of the B cell memory compartment, in their temporal kinetics, antigen-binding capacities and association with cTFH cells, and are important parameters for consideration in assessing vaccine-induced immune responses.

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