IgM+ and IgT+ B Cell Traffic to the Heart during SAV Infection in Atlantic Salmon

B cells of teleost fish differentiate in the head kidney, and spleen, and either remain in the lymphatic organs or move to the blood and peripheral tissues. There is limited knowledge about piscine B cell traffic to sites of vaccination and infection and their functional roles at these sites. In this work, we examined the traffic of B cells in Atlantic salmon challenged with salmonid alphavirus (SAV). In situ hybridization (RNAScope) showed increased numbers of immunoglobin (Ig)M+ and IgT+ B cells in the heart in response to SAV challenge, with IgM+ B cells being most abundant. An increase in IgT+ B cells was also evident, indicating a role of IgT+ B cells in nonmucosal tissues and systemic viral infections. After infection, B cells were mainly found in the stratum spongiosum of the cardiac ventricle, colocalizing with virus-infected myocardial-like cells. From sequencing the variable region of IgM in the main target organ (heart) and comparing it with a major lymphatic organ (the spleen), co-occurrence in antibody repertoires indicated a transfer of B cells from the spleen to the heart, as well as earlier recruitment of B cells to the heart in vaccinated fish compared to those that were unvaccinated. Transcriptome analyses performed at 21 days post-challenge suggested higher expression of multiple mediators of inflammation and lymphocyte-specific genes in unvaccinated compared to vaccinated fish, in parallel with a massive suppression of genes involved in heart contraction, metabolism, and development of tissue. The adaptive responses to SAV in vaccinated salmon appeared to alleviate the disease. Altogether, these results suggest that migration of B cells from lymphatic organs to sites of infection is an important part of the adaptive immune response of Atlantic salmon to SAV.

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CXCR5+CD8+ T Cells Shape Antibody Responses In Vivo Following Protein Immunisation and Peripheral Viral Infection

Frontiers in Immunology ◽

10.3389/fimmu.2021.626199 ◽

2021 ◽

Vol 12 ◽

Author(s):

Timona S. Tyllis ◽

Kevin A. Fenix ◽

Todd S. Norton ◽

Ervin E. Kara ◽

Duncan R. McKenzie ◽

...

Keyword(s):

T Cells ◽

B Cells ◽

Viral Infection ◽

B Cell ◽

Viral Infections ◽

Antibody Responses ◽

Infection Model ◽

Peripheral Tissues ◽

Tfh Cells

Crosstalk between T and B cells is crucial for generating high-affinity, class-switched antibody responses. The roles of CD4+ T cells in this process have been well-characterised. In contrast, regulation of antibody responses by CD8+ T cells is significantly less defined. CD8+ T cells are principally recognised for eliciting cytotoxic responses in peripheral tissues and forming protective memory. However, recent findings have identified a novel population of effector CD8+ T cells that co-opt a differentiation program characteristic of CD4+ T follicular helper (Tfh) cells, upregulate the chemokine receptor CXCR5 and localise to B cell follicles. While it has been shown that CXCR5+CD8+ T cells mediate the removal of viral reservoirs in the context of follicular-trophic viral infections and maintain the response to chronic insults by virtue of progenitor/stem-like properties, it is not known if CXCR5+CD8+ T cells arise during acute peripheral challenges in the absence of follicular infection and whether they influence B cell responses in vivo in these settings. Using the ovalbumin-specific T cell receptor transgenic (OT-I) system in an adoptive transfer-immunisation/infection model, this study demonstrates that CXCR5+CD8+ T cells arise in response to protein immunisation and peripheral viral infection, displaying a follicular-homing phenotype, expression of cell surface molecules associated with Tfh cells and limited cytotoxic potential. Furthermore, studies assessing the B cell response in the presence of OT-I or Cxcr5-/- OT-I cells revealed that CXCR5+CD8+ T cells shape the antibody response to protein immunisation and peripheral viral infection, promoting class switching to IgG2c in responding B cells. Overall, the results highlight a novel contribution of CD8+ T cells to antibody responses, expanding the functionality of the adaptive immune system.

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Pro-Inflammatory and B Cell Regulating Capacities of TWEAK in Rainbow Trout (Oncorhynchus mykiss)

Frontiers in Immunology ◽

10.3389/fimmu.2021.748836 ◽

2021 ◽

Vol 12 ◽

Author(s):

Beatriz Abós ◽

Elena Pérez-Fernández ◽

Esther Morel ◽

Pedro Perdiguero ◽

Carolina Tafalla

Keyword(s):

Rainbow Trout ◽

B Cells ◽

Oncorhynchus Mykiss ◽

B Cell ◽

Teleost Fish ◽

Viral Infections ◽

Biological Effects ◽

Head Kidney ◽

B Cell Differentiation ◽

Inflammatory Genes

Tumor necrosis factor (TNF)-like weak inducer of apoptosis or TWEAK is a member of the TNF superfamily involved in the regulation of many biological processes. In mammals, TWEAK has been shown to play a role in some autoimmune or inflammatory conditions, but its immune role is not yet clearly defined. In teleost fish, although a few studies have identified homologues to mammalian TWEAK, their biological effects have never been investigated. In the current study, we have studied the transcriptional regulation of two TWEAK homologues (TWEAK 1 and 2) identified in rainbow trout (Oncorhynchus mykiss) throughout different tissues, in response to parasitic or viral infections, or in head kidney (HK) leukocytes stimulated with different stimuli. Although the transcription of both homologues was modulated when HK leukocytes were exposed to several immune stimuli, only TWEAK 1 was significantly modulated upon pathogenic exposure. Thus, we performed a characterization of the functions exerted by this cytokine in HK leukocytes. Recombinant TWEAK 1 strongly up-regulated the transcription of pro-inflammatory genes and antimicrobial peptides in HK leukocytes, with differential transcriptional effects in IgM+ B cells, IgM- lymphocytes and myeloid cells. TWEAK 1 also increased the survival and promoted the differentiation of B cells in HK leukocyte cultures. Our results demonstrate that in teleost fish, TWEAK 1 is involved in the response to different types of pathogens, through the modulation of antimicrobial and pro-inflammatory genes in different leukocytes subsets. Furthermore, a role for TWEAK as a B cell differentiation factor has also been established in rainbow trout.

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Deficiency of the B Cell-Activating Factor Receptor Results in Limited CD169+Macrophage Function during Viral Infection

Journal of Virology ◽

10.1128/jvi.02976-14 ◽

2015 ◽

Vol 89 (9) ◽

pp. 4748-4759 ◽

Cited By ~ 13

Author(s):

Haifeng C. Xu ◽

Jun Huang ◽

Vishal Khairnar ◽

Vikas Duhan ◽

Aleksandra A. Pandyra ◽

...

Keyword(s):

B Cells ◽

Viral Infection ◽

B Cell ◽

Viral Infections ◽

Type I Interferon ◽

Type I ◽

Interferon Production ◽

Immune Priming ◽

Adaptive Immune ◽

Deficient Mice

ABSTRACTThe B cell-activating factor (BAFF) is critical for B cell development and humoral immunity in mice and humans. While the role of BAFF in B cells has been widely described, its role in innate immunity remains unknown. Using BAFF receptor (BAFFR)-deficient mice, we characterized BAFFR-related innate and adaptive immune functions following infection with vesicular stomatitis virus (VSV) and lymphocytic choriomeningitis virus (LCMV). We identified a critical role for BAFFR signaling in the generation and maintenance of the CD169+macrophage compartment. Consequently,Baffr−/−mice exhibited limited induction of innate type I interferon production after viral infection. Lack of BAFFR signaling reduced virus amplification and presentation following viral infection, resulting in highly reduced antiviral adaptive immune responses. As a consequence, BAFFR-deficient mice showed exacerbated and fatal disease after viral infection. Mechanistically, transient lack of B cells inBaffr−/−animals resulted in limited lymphotoxin expression, which is critical for maintenance of CD169+cells. In conclusion, BAFFR signaling affects both innate and adaptive immune activation during viral infections.IMPORTANCEViruses cause acute and chronic infections in humans resulting in millions of deaths every year. Innate immunity is critical for the outcome of a viral infection. Innate type I interferon production can limit viral replication, while adaptive immune priming by innate immune cells induces pathogen-specific immunity with long-term protection. Here, we show that BAFFR deficiency not only perturbed B cells, but also resulted in limited CD169+macrophages. These macrophages are critical in amplifying viral particles to trigger type I interferon production and initiate adaptive immune priming. Consequently, BAFFR deficiency resulted in reduced enforced viral replication, limited type I interferon production, and reduced adaptive immunity compared to BAFFR-competent controls. As a result, BAFFR-deficient mice were predisposed to fatal viral infections. Thus, BAFFR expression is critical for innate immune activation and antiviral immunity.

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Death by a B Cell Superantigen

Journal of Experimental Medicine ◽

10.1084/jem.20020552 ◽

2003 ◽

Vol 197 (9) ◽

pp. 1125-1139 ◽

Cited By ~ 108

Author(s):

Carl S. Goodyear ◽

Gregg J. Silverman

Keyword(s):

B Cells ◽

B Cell ◽

Protein A ◽

Death Receptor ◽

Variable Region ◽

Microbial Pathogens ◽

Host Immune System ◽

Antigen Receptors ◽

Sequence Of Events

Amongst the many ploys used by microbial pathogens to interfere with host immune responses is the production of proteins with the properties of superantigens. These properties enable superantigens to interact with conserved variable region framework subdomains of the antigen receptors of lymphocytes rather than the complementarity determining region involved in the binding of conventional antigens. To understand how a B cell superantigen affects the host immune system, we infused protein A of Staphylococcus aureus (SpA) and followed the fate of peripheral B cells expressing B cell receptors (BCRs) with VH regions capable of binding SpA. Within hours, a sequence of events was initiated in SpA-binding splenic B cells, with rapid down-regulation of BCRs and coreceptors, CD19 and CD21, the induction of an activation phenotype, and limited rounds of proliferation. Apoptosis followed through a process heralded by the dissipation of mitochondrial membrane potential, the induction of the caspase pathway, and DNA fragmentation. After exposure, B cell apoptotic bodies were deposited in the spleen, lymph nodes, and Peyer's patches. Although in vivo apoptosis did not require the Fas death receptor, B cells were protected by interleukin (IL)-4 or CD40L, or overexpression of Bcl-2. These studies define a pathway for BCR-mediated programmed cell death that is VH region targeted by a superantigen.

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Reprogramming the antigen specificity of B cells using genomeediting technologies

10.1101/455402 ◽

2018 ◽

Cited By ~ 1

Author(s):

James E. Voss ◽

Alicia Gonzalez-Martin ◽

Raiees Andrabi ◽

Roberta P. Fuller ◽

Ben Murrell ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Cytidine Deaminase ◽

Variable Region ◽

Neutralizing Antibody ◽

Surface Expression ◽

Affinity Maturation ◽

Cell Surface Expression ◽

Human Antibody ◽

Antigen Specificity

We have developed a method to introduce novel paratopes into the human antibody repertoire by modifying the immunoglobulin genes of mature B cells directly using genome editing technologies. We used CRISPR-Cas9 in a homology directed repair strategy, to replace the heavy chain (HC) variable region in B cell lines with that from an HIV broadly neutralizing antibody, PG9. Our strategy is designed to function in cells that have undergone VDJ recombination using any combination of variable (V), diversity (D) and joining (J) genes. The modified locus expresses PG9 HC which pairs with native light chains resulting in the cell surface expression of HIV specific B cell receptors (BCRs). Endogenous activation-induced cytidine deaminase (AID) in engineered cells allowed for Ig class switching and generated BCR variants with improved anti-HIV neutralizing activity. Thus, BCRs engineered in this way retain the genetic flexibility normally required for affinity maturation during adaptive immune responses.

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Bone marrow origin of a B-cell lymphoma

Blood ◽

10.1182/blood.v72.1.94.bloodjournal72194 ◽

1988 ◽

Vol 72 (1) ◽

pp. 94-101

Author(s):

LF Bertoli ◽

H Kubagawa ◽

GV Borzillo ◽

PD Burrows ◽

MT Schreeder ◽

...

Keyword(s):

Bone Marrow ◽

B Cells ◽

B Cell ◽

Cell Lymphoma ◽

Variable Region ◽

B Cell Lymphoma ◽

Large Cell ◽

Low Grade ◽

Immunoglobulin Gene ◽

B Lineage

To search for precursors of the neoplastic B cells in a patient with a nodular lymphoma, we produced a monoclonal antibody to a variable region idiotope on the lymphoma IgM heavy chain. Clonal ancestors of the lymphoma cells were identified by this marker among bone marrow pre- B cells (5% to 26%). A second antiidiotype (anti-Id) antibody specific for the complete lymphoma IgM kappa recognized 10% of B cells in bone marrow and blood and greater than 95% of B cells in lymphomatous lymph nodes, including one obtained after tumor conversion to a diffuse large cell lymphoma. Immunoglobulin gene analysis surprisingly revealed expansion of multiple clones of early B lineage cells in bone marrow, including members of the neoplastic clone. The data suggest that this lymphoma arose through a progression of transformational events beginning in bone marrow: first, creation of an oligoclonal pre- neoplastic pool of pre-B cells, subsequent conversion of a single subclone into low grade neoplastic B cells that homed to the lymph node follicles, and later progression to a more invasive form of the B-cell lymphoma.

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Human germinal center B cells express the apoptosis-inducing genes Fas, c-myc, P53, and Bax but not the survival gene bcl-2.

Journal of Experimental Medicine ◽

10.1084/jem.183.3.971 ◽

1996 ◽

Vol 183 (3) ◽

pp. 971-977 ◽

Cited By ~ 156

Author(s):

H Martinez-Valdez ◽

C Guret ◽

O de Bouteiller ◽

I Fugier ◽

J Banchereau ◽

...

Keyword(s):

Cell Cycle ◽

B Cells ◽

B Cell ◽

Germinal Center ◽

Somatic Hypermutation ◽

Cell Subset ◽

Variable Region ◽

Negative Regulator ◽

Memory B Cell ◽

Survival Gene

During T cell-dependent antibody responses, B cells within germinal centers (GC) alter the affinity of their antigen receptor by introducing somatic mutations into variable region of immunoglobulin (IgV) genes. During this process, GC B cells are destined to die unless positively selected by antigens and CD40-ligand. To understand survival/death control of germinal center B cell, the expression of four apoptosis-inducing genes, Fas, c-myc, Bax, and P53, together with the survival gene bcl-2, has been analyzed herein among purified tonsillar naive, GC, and memory B cells. IgD+CD38- naive B cells were separated into CD23- (mature B cell [Bm]1) subset and CD23+ (Bm2), IgD-CD38+ GC B cells were separated into subsets of CD77+ centroblasts (Bm3) and CD77- centrocytes (Bm4), whereas IgD-CD38- cells represented the Bm5 memory B cell subset. Sequence analysis of IgV region genes indicated that somatic hypermutation was triggered in the Bm3 centroblast subset. Here we show that bcl-2 is only detectable with naive (Bm1 and 2) and memory B cell (Bm5) subsets, whereas all four apoptosis-inducing genes were most significantly expressed within GC B cells. Fas was equally expressed in Bm3 centroblasts and Bm4 centrocytes, whereas Bax was most significantly expressed in Bm4 centrocytes. c-myc, a positive regulator of cell cycle, was most significantly expressed in proliferating Bm3 centroblasts, whereas P53, a negative regulator of cell cycle, was most signficantly expressed in nonproliferating Bm4 centrocytes. The present results indicate that the survival/death of GC B cells are regulated by the up- and downregulation of multiple genes, among which the expression of c-myc and P53 in the absence of bcl-2 may prime the proliferating Bm3 centroblasts and nonproliferating Bm4 centrocytes to apoptosis.

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IRF-4/MUM-1 Expression Is a Critical Switch in the Generation of Plasma Cells Versus Memory B-Cells.

Blood ◽

10.1182/blood.v106.11.337.337 ◽

2005 ◽

Vol 106 (11) ◽

pp. 337-337 ◽

Cited By ~ 2

Author(s):

Ulf Klein ◽

Stefano Casola ◽

Giorgio Cattoretti ◽

Qiong Shen ◽

Marie Lia ◽

...

Keyword(s):

B Cells ◽

Transgenic Mice ◽

B Cell ◽

Plasma Cells ◽

Large Fraction ◽

Variable Region ◽

Memory B Cells ◽

Critical Event ◽

Tumor Subtypes

Abstract Most types of human B-cell lymphomas harbor somatically mutated Ig variable region genes, reflecting their origin from cells that have undergone the germinal center (GC) reaction of T-dependent immune responses. The lymphomas exhibit diverse phenotypes and clinical behaviors, likely as a consequence of differences both in the mechanisms of transformation and in the specific target cell. We have recently identified two distinct subsets of GC B-cells that may represent late stages of the GC-reaction and may be the precursors of plasma cells and memory B-cells. The corresponding subsets are characterized by downregulation of the GC-marker BCL6 and the alternative expression of IRF-4/MUM-1 or nuclear c-Rel. These two subsets seem to reflect distinct cellular programs which are altered during B-lymphomagenesis in various tumor subtypes which co-express BCL6, IRF-4 and nuclear c-Rel, an event never observed in normal B-cells. In order to gain insights into the physiologic role of IRF-4/MUM-1 and nuclear c-Rel in GC-development, we are ablating their expression specifically in mouse GC B-cells. Transgenic mice were generated that carry an IRF-4/MUM-1 null allele and a conditional IRF-4/MUM-1 allele which, following Cre-mediated deletion of the loxP-flanked promotor region and exons 1 and 2, expresses eGFP, thus allowing to track the development of the IRF-4/MUM-1 deficient cells at the single cell level. IRF-4/MUM-1fl/- mice were crossed with transgenic mice that express the Cre-recombinase specifically in B-cells undergoing class-switch to IgG1, an event occurring in a large fraction of GC B-cells. Upon immunization with sheep red blood cells or nitrophenyl-(NP)-KLH, mice unable to express IRF-4/MUM-1 in late GC B-cells (IRF-4/MUM-1fl/-/Cγ 1Cre/+), in contrast to control mice (IRF-4/MUM-1fl/+/Cγ 1Cre/+), did not develop plasma cells (IgG1+CD138+) in the peripheral lymphoid organs, blood, and bone marrow. On the other hand, the generation of memory B-cells appears normal since antigen-specific B-cells were present in the spleen (eGFP+B220+PNA-IgG1+) and blood (eGFP+B220+CD38+IgG1+). These results suggest that the IRF-4/MUM-1 gene product is required for the development of antigen-selected GC B-cells into plasma cells. We suggest that the expression of IRF-4/MUM-1 in a GC centrocyte is the critical event in the commitment of B-cells to differentiate into a plasma cell versus a memory B-cell, and are currently testing the role of nuclear c-Rel in the same process.

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Bone marrow origin of a B-cell lymphoma

Blood ◽

10.1182/blood.v72.1.94.94 ◽

1988 ◽

Vol 72 (1) ◽

pp. 94-101 ◽

Cited By ~ 25

Author(s):

LF Bertoli ◽

H Kubagawa ◽

GV Borzillo ◽

PD Burrows ◽

MT Schreeder ◽

...

Keyword(s):

Bone Marrow ◽

B Cells ◽

B Cell ◽

Cell Lymphoma ◽

Variable Region ◽

B Cell Lymphoma ◽

Large Cell ◽

Low Grade ◽

Immunoglobulin Gene ◽

B Lineage

Abstract To search for precursors of the neoplastic B cells in a patient with a nodular lymphoma, we produced a monoclonal antibody to a variable region idiotope on the lymphoma IgM heavy chain. Clonal ancestors of the lymphoma cells were identified by this marker among bone marrow pre- B cells (5% to 26%). A second antiidiotype (anti-Id) antibody specific for the complete lymphoma IgM kappa recognized 10% of B cells in bone marrow and blood and greater than 95% of B cells in lymphomatous lymph nodes, including one obtained after tumor conversion to a diffuse large cell lymphoma. Immunoglobulin gene analysis surprisingly revealed expansion of multiple clones of early B lineage cells in bone marrow, including members of the neoplastic clone. The data suggest that this lymphoma arose through a progression of transformational events beginning in bone marrow: first, creation of an oligoclonal pre- neoplastic pool of pre-B cells, subsequent conversion of a single subclone into low grade neoplastic B cells that homed to the lymph node follicles, and later progression to a more invasive form of the B-cell lymphoma.

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Functional anergy in a subpopulation of naive B cells from healthy humans that express autoreactive immunoglobulin receptors

Journal of Experimental Medicine ◽

10.1084/jem.20080611 ◽

2008 ◽

Vol 206 (1) ◽

pp. 139-151 ◽

Cited By ~ 139

Author(s):

J. Andrew Duty ◽

Peter Szodoray ◽

Nai-Ying Zheng ◽

Kristi A. Koelsch ◽

Qingzhao Zhang ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Lupus Erythematosus ◽

Plasma Cells ◽

Cell Subset ◽

Variable Region ◽

Cell Receptor ◽

Clonal Deletion ◽

Healthy Humans ◽

Human B Cells

Self-reactive B cells not controlled by receptor editing or clonal deletion may become anergic. We report that fully mature human B cells negative for surface IgM and retaining only IgD are autoreactive and functionally attenuated (referred to as naive IgD+IgM− B cells [BND]). These BND cells typically make up 2.5% of B cells in the peripheral blood, have antibody variable region genes in germline (unmutated) configuration, and, by all current measures, are fully mature. Analysis of 95 recombinant antibodies expressed from the variable genes of single BND cells demonstrated that they are predominantly autoreactive, binding to HEp-2 cell antigens and DNA. Upon B cell receptor cross-linkage, BND cells have a reduced capacity to mobilize intracellular calcium or phosphorylate tyrosines, demonstrating that they are anergic. However, intense stimulation causes BND cells to fully respond, suggesting that these cells could be the precursors of autoantibody secreting plasma cells in autoimmune diseases such as systemic lupus erythematosus or rheumatoid arthritis. This is the first identification of a distinct mature human B cell subset that is naturally autoreactive and controlled by the tolerizing mechanism of functional anergy.

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