scholarly journals Antibody to a Lytic Cycle Viral Protein Decreases Gammaherpesvirus Latency in B-Cell-Deficient Mice

2002 ◽  
Vol 76 (22) ◽  
pp. 11460-11468 ◽  
Author(s):  
Shivaprakash Gangappa ◽  
Sharookh B. Kapadia ◽  
Samuel H. Speck ◽  
Herbert W. Virgin
Keyword(s):  
B Cells ◽  
B Cell ◽  
Viral Genome ◽  
Ex Vivo ◽  
Critical Role ◽  
Passive Transfer ◽  
Lytic Cycle ◽  
Peritoneal Cells ◽  
Latently Infected ◽  
Immunocompromised Hosts

ABSTRACT While antiviral antibody plays a key role in resistance to acute viral infection, the contribution of antibody to the control of latent virus infection is less well understood. Gammaherpesvirus 68 (γHV68) infection of mice provides a model well suited to defining contributions of specific immune system components to the control of viral latency. B cells play a critical role in regulating γHV68 latency, but the mechanism(s) by which B cells regulate latency is not known. In the experiments reported here, we determined the effect of passively transferred antibody on established γHV68 latency in B-cell-deficient (B-cell−/−) mice. Immune antibody decreased the frequency of cells reactivating ex vivo from latency in splenocytes (>10-fold) and peritoneal cells (>100-fold) and the frequency of cells carrying latent viral genome in splenocytes (>5-fold) and peritoneal cells (>50-fold). This effect required virus-specific antibody and was observed when total and virus-specific serum antibody concentrations in recipient B-cell−/− mice were <8% of those in normal mice during latent infection. Passive transfer of antibody specific for the lytic cycle γHV68 RCA protein, but not passive transfer of antibody specific for the v-cyclin protein or the latent protein M2, decreased both the frequency of cells reactivating ex vivo from latency and the frequency of cells carrying the latent viral genome. Therefore, antibody specific for lytic cycle viral antigens can play an important role in the control of gammaherpesvirus latency in immunocompromised hosts. Based on these findings, we propose a model in which ongoing productive replication is essential for maintaining high levels of latently infected cells in immunocompromised hosts. We confirmed this model by the treatment of latently infected B-cell−/− mice with the antiviral drug cidofovir.

scholarly journals Ex Vivo Stimulation of B Cells Latently Infected with Gammaherpesvirus 68 Triggers Reactivation from Latency

2005 ◽  
Vol 79 (8) ◽  
pp. 5227-5231 ◽  
Author(s):  
Janice M. Moser ◽  
Jason W. Upton ◽  
Kathleen S. Gray ◽  
Samuel H. Speck
Keyword(s):  
Cell Proliferation ◽  
B Cells ◽  
B Cell ◽  
Ex Vivo ◽  
Virus Reactivation ◽  
Latently Infected ◽  
Cd40 Stimulation ◽  
Gammaherpesvirus 68 ◽  
Spontaneous Reactivation ◽  
Stimulation Of

ABSTRACT Murine gammaherpesvirus 68 (γHV68) infection of mice results in the establishment of a chronic infection, which is largely maintained through latent infection of B lymphocytes. Acute virus replication is almost entirely cleared by 2 weeks postinfection. Spontaneous reactivation of γHV68 from latently infected splenocytes upon ex vivo culture can readily be detected at the early stages of infection (e.g., day 16). However, by 6 weeks postinfection, very little spontaneous reactivation is detected upon explant into tissue culture. Here we report that stimulation of latently infected splenic B cells harvested at late times postinfection with cross-linking surface immunoglobulin (Ig), in conjunction with anti-CD40 antibody treatment, triggers virus reactivation. As expected, this treatment resulted in B-cell activation, as assessed by upregulation of CD69 on B cells, and ultimately B-cell proliferation. Since anti-Ig/anti-CD40 stimulation resulted in splenic B-cell proliferation, we assessed whether this reactivation stimulus could overcome the previously characterized defect in virus reactivation of a v-cyclin null γHV68 mutant. This analysis demonstrated that anti-Ig/anti-CD40 stimulation could drive reactivation of the v-cyclin null mutant virus in latently infected splenocytes, but not to the levels observed with wild-type γHV68. Thus, there appears to be a role for the v-cyclin in B cells following anti-Ig/anti-CD40 stimulation independent of the induction of the cell cycle. Finally, to assess signals that are not mediated through the B-cell receptor, we demonstrate that addition of lipopolysaccharide to explanted splenocyte cultures also enhanced virus reactivation. These studies complement and extend previous analyses of Epstein-Barr virus and Kaposi's sarcoma-associated virus reactivation from latently infected cell lines by investigating reactivation of γHV68 from latently infected primary B cells recovered from infected hosts.

scholarly journals The aryl hydrocarbon receptor controls cell-fate decisions in B cells

2016 ◽  
Vol 214 (1) ◽  
pp. 197-208 ◽  
Author(s):  
Bharat Vaidyanathan ◽  
Ashutosh Chaudhry ◽  
William T. Yewdell ◽  
Davide Angeletti ◽  
Wei-Feng Yen ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Aryl Hydrocarbon Receptor ◽  
Cell Fate ◽  
Plasma Cells ◽  
Ex Vivo ◽  
Critical Role ◽  
Cell Fate Decisions ◽  
Aryl Hydrocarbon

Generation of cellular heterogeneity is an essential feature of the adaptive immune system. This is best exemplified during humoral immune response when an expanding B cell clone assumes multiple cell fates, including class-switched B cells, antibody-secreting plasma cells, and memory B cells. Although each cell type is essential for immunity, their generation must be exquisitely controlled because a class-switched B cell cannot revert back to the parent isotype, and a terminally differentiated plasma cell cannot contribute to the memory pool. In this study, we show that an environmental sensor, the aryl hydrocarbon receptor (AhR) is highly induced upon B cell activation and serves a critical role in regulating activation-induced cell fate outcomes. We find that AhR negatively regulates class-switch recombination ex vivo by altering activation-induced cytidine deaminase expression. We further demonstrate that AhR suppresses class switching in vivo after influenza virus infection and immunization with model antigens. In addition, by regulating Blimp-1 expression via Bach2, AhR represses differentiation of B cells into plasmablasts ex vivo and antibody-secreting plasma cells in vivo. These experiments suggest that AhR serves as a molecular rheostat in B cells to brake the effector response, possibly to facilitate optimal recall responses. Thus, AhR might represent a novel molecular target for manipulation of B cell responses during vaccination.

scholarly journals Lytic Replication and Reactivation from B cells Is Not Required for Maintaining Gammaherpesvirus Latency in vivo

2021 ◽  
Author(s):  
Arundahti Gupta ◽  
Shana Michelle Owens ◽  
Darby G. Oldenburg ◽  
Douglas W White ◽  
James Craig Forrest
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Activation ◽  
Ex Vivo ◽  
Antiviral Drug ◽  
Lytic Replication ◽  
Viral Reactivation ◽  
Transcription Activator ◽  
Murine Gammaherpesvirus ◽  
Latently Infected

Gammaherpesviruses (GHVs) are lymphotropic tumor viruses with a biphasic infectious cycle. Lytic replication at the primary site of infection is necessary for GHVs to spread throughout the host and establish latency in distal sites. Dissemination is mediated by infected B cells that traffic hematogenously from draining lymph nodes to peripheral lymphoid organs, such as the spleen. B cells serve as the major reservoir for viral latency, and it is hypothesized that periodic reactivation from latently infected B cells contributes to maintaining long-term chronic infection. While fundamentally important to an understanding of GHV biology, aspects of B cell infection in latency establishment and maintenance are incompletely defined, especially roles for lytic replication and reactivation in this cell type. To address this knowledge gap and overcome limitations of replication-defective viruses, we generated a recombinant murine gammaherpesvirus 68 (MHV68) in which ORF50, the gene that encodes the essential immediate-early replication and transcription activator protein (RTA), was flanked by loxP sites to enable conditional ablation of lytic replication by ORF50 deletion in cells that express Cre recombinase. Following infection of mice that encode Cre in B cells with this virus, splenomegaly and viral reactivation from splenocytes were significantly reduced, however the number of latently infected splenocytes was equivalent to WT MHV68. Despite ORF50 deletion, MHV68 latency was maintained over time in spleens of mice at levels approximating WT, reactivation-competent MHV68. Stimulation of polyclonal B cell activation and proliferation by treating mice with lipopolysaccharide (LPS), which promotes MHV68 reactivation ex vivo, yielded equivalent increases in the number of latently infected cells for both ORF50-deleted and WT MHV68, even when mice were simultaneously treated with the antiviral drug cidofovir. Together, these data demonstrate that lytic replication in B cells is not required for MHV68 latency establishment and maintenance and further indicate that B cell proliferation, and not reactivation per se, is a major mechanism for maintaining latent viral genomes in the host.

scholarly journals Hyaluronate-CD44 Interactions Can Induce Murine B-Cell Activation

Blood ◽  
1997 ◽  
Vol 89 (8) ◽  
pp. 2901-2908 ◽  
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.

scholarly journals Down-regulation of BLIMP1α by the EBV oncogene, LMP-1, disrupts the plasma cell differentiation program and prevents viral replication in B cells: implications for the pathogenesis of EBV-associated B-cell lymphomas

Blood ◽  
2011 ◽  
Vol 117 (22) ◽  
pp. 5907-5917 ◽  
Author(s):  
Katerina Vrzalikova ◽  
Martina Vockerodt ◽  
Sarah Leonard ◽  
Andrew Bell ◽  
Wenbin Wei ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
B Cells ◽  
B Cell ◽  
Virus Replication ◽  
Plasma Cell ◽  
Germinal Center ◽  
Lytic Cycle ◽  
Transformed Cells ◽  
Down Regulation ◽  
Plasma Cell Differentiation

AbstractAn important pathogenic event in Epstein-Barr virus (EBV)-associated lymphomas is the suppression of virus replication, which would otherwise lead to cell death. Because virus replication in B cells is intimately linked to their differentiation toward plasma cells, we asked whether the physiologic signals that drive normal B-cell differentiation are absent in EBV-transformed cells. We focused on BLIMP1α, a transcription factor that is required for plasma cell differentiation and that is inactivated in diffuse large B-cell lymphomas. We show that BLIMP1α expression is down-regulated after EBV infection of primary germinal center B cells and that the EBV oncogene, latent membrane protein-1 (LMP-1), is alone capable of inducing this down-regulation in these cells. Furthermore, the down-regulation of BLIMP1α by LMP-1 was accompanied by a partial disruption of the BLIMP1α transcriptional program, including the aberrant induction of MYC, the repression of which is required for terminal differentiation. Finally, we show that the ectopic expression of BLIMP1α in EBV-transformed cells can induce the viral lytic cycle. Our results suggest that LMP-1 expression in progenitor germinal center B cells could contribute to the pathogenesis of EBV-associated lymphomas by down-regulating BLIMP1α, in turn preventing plasma cell differentiation and induction of the viral lytic cycle.

IMMU-29. B-CELL-BASED VACCINE PRODUCES GLIOBLASTOMA-REACTIVE ANTIBODIES THAT CONTRIBUTE TO TUMOR CLEARANCE

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi98-vi98
Author(s):  
Brandyn Castro ◽  
Mark Dapash ◽  
David Hou ◽  
Aida Rashidi ◽  
Deepak Kanojia ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Humoral Immunity ◽  
Ex Vivo ◽  
Murine Models ◽  
Effector Functions ◽  
Tumor Bearing ◽  
Tumor Clearance ◽  
Cellular And Humoral Immunity

Abstract Glioblastomas (GBM) are characterized by a strong immunosuppressive environment, contributing to their poor prognosis and limited therapeutic response to immunotherapies. B-cells represent a unique opportunity to promote immunotherapy due to their potential to kill tumors by both cellular and humoral immunity. To generate our B-cell-based vaccine (BVax) platform, we activated 41BBL+ B cells from tumor bearing mice or GBM patient blood with BAFF, CD40, and IFNg. We have previously demonstrated that BVax potentiates radiation therapy, temozolomide and checkpoint blockade in murine models of GBM via enhancement of CD8+ T-cell based immunity. The aim of this current study is to evaluate the humoral effector functions of BVax. We examined the antibody (Ab) repertoire in vivo from serum of tumor-bearing B-cell knockout mice treated with BVax or by ex vivo stimulation of patient-derived BVax. Upon systemic administration, BVax infiltrates the tumor where it differentiates into plasmablasts. Murine BVax- and BNaive-derived serum immunoglobulin generated in vivo showed that the majority of murine BVax-derived Ab were IgG isotype, while BNaive mainly produced IgM isotype. Transfer of IgG from BVax treated mice directly into tumors of recipient animals significantly prolonged their survival, demonstrating anti-tumor cytotoxicity directly through humoral immunity. Patient-derived BVax activated ex vivo showed a plasmablast phenotype and the Ab repertoire supports the previous findings seen in our murine model. Our work suggests BVax-derived IgGs role in antibody-dependent cellular cytotoxicity and improved survival in murine models. This function, in addition to its role in cellular immunity against GBM, renders BVax a potentially effective alternative immunotherapeutic option for GBM patients.

scholarly journals Dual T cell– and B cell–intrinsic deficiency in humans with biallelic RLTPR mutations

2016 ◽  
Vol 213 (11) ◽  
pp. 2413-2435 ◽  
Author(s):  
Yi Wang ◽  
Cindy S. Ma ◽  
Yun Ling ◽  
Aziz Bousfiha ◽  
Yildiz Camcioglu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cd4 T Cells ◽  
Ex Vivo ◽  
Cell Phenotype ◽  
Loss Of Function ◽  
Inborn Errors

Combined immunodeficiency (CID) refers to inborn errors of human T cells that also affect B cells because of the T cell deficit or an additional B cell–intrinsic deficit. In this study, we report six patients from three unrelated families with biallelic loss-of-function mutations in RLTPR, the mouse orthologue of which is essential for CD28 signaling. The patients have cutaneous and pulmonary allergy, as well as a variety of bacterial and fungal infectious diseases, including invasive tuberculosis and mucocutaneous candidiasis. Proportions of circulating regulatory T cells and memory CD4+ T cells are reduced. Their CD4+ T cells do not respond to CD28 stimulation. Their CD4+ T cells exhibit a "Th2" cell bias ex vivo and when cultured in vitro, contrasting with the paucity of "Th1," "Th17," and T follicular helper cells. The patients also display few memory B cells and poor antibody responses. This B cell phenotype does not result solely from the T cell deficiency, as the patients’ B cells fail to activate NF-κB upon B cell receptor (BCR) stimulation. Human RLTPR deficiency is a CID affecting at least the CD28-responsive pathway in T cells and the BCR-responsive pathway in B cells.

scholarly journals A reverse translational study on the effect of rituximab, rituximab plus belimumab, or bortezomib on the humoral autoimmune response in SLE

Rheumatology ◽  
2020 ◽  
Vol 59 (10) ◽  
pp. 2734-2745 ◽  
Author(s):  
Laura S van Dam ◽  
Zgjim Osmani ◽  
Sylvia W A Kamerling ◽  
Tineke Kraaij ◽  
Jaap A   Bakker ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Randomized Clinical Trials ◽  
Ex Vivo ◽  
Neutrophil Extracellular Trap ◽  
Autoimmune Response ◽  
High Avidity ◽  
Trap Formation ◽  
Extracellular Trap ◽  
The Impact

Abstract Objectives SLE is a severe autoimmune disease characterized by autoreactive B cells and IC formation, which causes systemic inflammation. B cell–targeted therapy could be a promising treatment strategy in SLE patients; nevertheless, randomized clinical trials have not always been successful. However, some groups have demonstrated beneficial effects in severe SLE patients with off-label rituximab (RTX) with belimumab (BLM), or bortezomib (BTZ), which targeted different B cells subsets. This study assembled sera from SLE cohorts treated with RTX+BLM (n = 15), BTZ (n = 11) and RTX (n = 16) to get an in-depth insight into the immunological effects of these therapies on autoantibodies and IC formation. Methods Autoantibodies relevant for IC formation and the avidity of anti-dsDNA were determined by ELISA. IC-mediated inflammation was studied by complement levels and ex vivo serum-induced neutrophil extracellular trap formation. Results Reductions in autoantibodies were observed after all approaches, but the spectrum differed depending upon the treatment. Specifically, only RTX+BLM significantly decreased anti-C1q. Achieving seronegativity of ≥1 autoantibody, specifically anti-C1q, was associated with lower disease activity. In all SLE patients, the majority of anti-dsDNA autoantibodies had low avidity. RTX+BLM significantly reduced low-, medium- and high-avidity anti-dsDNA, while RTX and BTZ only significantly reduced medium avidity. IC-mediated inflammation, measured by C3 levels and neutrophil extracellular trap formation, improved after RTX+BLM and RTX but less after BTZ. Conclusion This study demonstrated the impact of different B cell–targeted strategies on autoantibodies and IC formation and their potential clinical relevance in SLE.

scholarly journals NR4A Expression by Human Marginal Zone B-Cells

Antibodies ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 50
Author(s):  
Kim Doyon-Laliberté ◽  
Josiane Chagnon-Choquet ◽  
Michelle Byrns ◽  
Matheus Aranguren ◽  
Meriam Memmi ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Population ◽  
Human Blood ◽  
Marginal Zone ◽  
Ex Vivo ◽  
Transcriptome Profiling ◽  
Marginal Zone B Cells ◽  
Healthy Donors ◽  
And Function

We have previously characterized a human blood CD19+CD1c+IgM+CD27+CD21loCD10+ innate-like B-cell population, which presents features shared by both transitional immature and marginal zone (MZ) B-cells, named herein “precursor-like” MZ B-cells. B-cells with similar attributes have been associated with regulatory potential (Breg). In order to clarify this issue and better characterize this population, we have proceeded to RNA-Seq transcriptome profiling of mature MZ and precursor-like MZ B-cells taken from the blood of healthy donors. We report that ex vivo mature MZ and precursor-like MZ B-cells express transcripts for the immunoregulatory marker CD83 and nuclear receptors NR4A1, 2, and 3, known to be associated with T-cell regulatory (Treg) maintenance and function. Breg associated markers such as CD39 and CD73 were also expressed by both populations. We also show that human blood and tonsillar precursor-like MZ B-cells were the main B-cell population to express elevated levels of CD83 and NR4A1-3 proteins ex vivo and without stimulation. Sorted tonsillar precursor-like MZ B-cells exerted regulatory activity on autologous activated CD4+ T-cells, and this was affected by a CD83 blocking reagent. We believe these observations shed light on the Breg potential of MZ populations, and identify NR4A1-3 as potential Breg markers, which as for Tregs, may be involved in stabilization of a regulatory status. Since expression and activity of these molecules can be modulated therapeutically, our findings may be useful in strategies aiming at modulation of Breg responses.

scholarly journals Splenic T Zone Development Is B Cell Dependent

2001 ◽  
Vol 194 (11) ◽  
pp. 1649-1660 ◽  
Author(s):  
Vu N. Ngo ◽  
Richard J. Cornall ◽  
Jason G. Cyster
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Critical Role ◽  
Early Postnatal Development ◽  
Cell Accumulation ◽  
Zone Development ◽  
Cell Expression ◽  
Immune Defects ◽  
B Cell Deficiency

The factors regulating growth and patterning of the spleen are poorly defined. We demonstrate here that spleens from B cell–deficient mice have 10-fold reduced expression of the T zone chemokine, CCL21, a threefold reduction in T cell and dendritic cell (DC) numbers, and reduced expression of the T zone stromal marker, gp38. Using cell transfer and receptor blocking approaches, we provide evidence that B cells play a critical role in the early postnatal development of the splenic T zone. This process involves B cell expression of lymphotoxin (LT)α1β2, a cytokine that is required for expression of CCL21 and gp38. Introduction of a B cell specific LTα transgene on to the LTα-deficient background restored splenic CCL21 and gp38 expression, DC numbers, and T zone size. This work also demonstrates that the role of B cells in T zone development is distinct from the effect of B cells on splenic T cell numbers, which does not require LTα1β2. Therefore, B cells influence spleen T zone development by providing: (a) signals that promote T cell accumulation, and: (b) signals, including LTα1β2, that promote stromal cell development and DC accumulation. Defects in these parameters may contribute to the immune defects associated with B cell deficiency in mice and humans.

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