scholarly journals Direct Infection of B Cells by Dengue Virus Modulates B Cell Responses in a Cambodian Pediatric Cohort

2021 ◽  
Vol 11 ◽  
Author(s):  
Vinit Upasani ◽  
Hoa Thi My Vo ◽  
Heidi Auerswald ◽  
Denis Laurent ◽  
Sothy Heng ◽  
...  
Keyword(s):  
B Cells ◽  
Dengue Virus ◽  
B Cell ◽  
Immune Cells ◽  
Cell Formation ◽  
Denv Infection ◽  
Cell Responses ◽  
B Cell Responses

Dengue is an acute viral disease caused by dengue virus (DENV), which is transmitted by Aedes mosquitoes. Symptoms of DENV infection range from inapparent to severe and can be life-threatening. DENV replicates in primary immune cells such as dendritic cells and macrophages, which contribute to the dissemination of the virus. Susceptibility of other immune cells such as B cells to direct infection by DENV and their subsequent response to infection is not well defined. In a cohort of 60 Cambodian children, we showed that B cells are susceptible to DENV infection. Moreover, we show that B cells can support viral replication of laboratory adapted and patient-derived DENV strains. B cells were permissive to DENV infection albeit low titers of infectious virions were released in cell supernatants CD300a, a phosphatidylserine receptor, was identified as a potential attachment factor or receptor for entry of DENV into B cells. In spite of expressing Fcγ-receptors, antibody-mediated enhancement of DENV infection was not observed in B cells in an in vitro model. Direct infection by DENV induced proliferation of B cells in dengue patients in vivo and plasmablast/plasma cell formation in vitro. To summarize, our results show that B cells are susceptible to direct infection by DENV via CD300a and the subsequent B cell responses could contribute to dengue pathogenesis.

Agonist for Toll-Like Receptor (TLR) 9 Amplifies as Well as Inhibits the Differentiation of FVIII-Specific Memory B Cells into Antibody-Producing Plasma Cells in Vitro and in Vivo.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3382-3382
Author(s):  
Peter Allacher ◽  
Christina Hausl ◽  
Aniko Ginta Pordes ◽  
Rafi Uddin Ahmad ◽  
Hartmut J Ehrlich ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Memory B Cells ◽  
Memory B Cell ◽  
Cpg Dna ◽  
Cell Responses ◽  
Specific Memory ◽  
B Cell Responses

Abstract Memory B cells are essential for maintaining long-term antibody responses. They can persist for years even in the absence of antigen and are rapidly re-stimulated to differentiate into antibody-producing plasma cells when they encounter their specific antigen. Previously we demonstrated that ligands for TLR 7 and 9 amplify the differentiation of FVIII-specific memory B cells into anti-FVIII antibody-producing plasma cells at low concentrations of FVIII and prevent the inhibition of memory-B-cell differentiation at high concentrations of FVIII. The modulation of FVIII-specific memory-B-cell responses by agonists for TLR is highly relevant for the design of new immunotherapeutic approaches in patients with FVIII inhibitors because TLR are activated by a range of different viral and bacterial components. Specifically, TLR 7 is triggered by single-stranded RNA derived from viruses and TLR 9 is triggered by bacterial DNA containing unmethylated CpG motifs. We further explored the modulation of FVIII-specific memory-B-cell responses by agonists for TLRs by studying a broad range of concentrations of CpG DNA, a ligand for TLR 9, both in vitro and in vivo using the murine E17 model of hemophilia A. We used CpG-DNA in concentrations ranging from 0.1 to 10,000 ng/ml to study the modulation of FVIII-specific memory-B-cell responses in vitro and verified the specificity of the effects observed by including a blocking agent for TLR 9 and GpC-DNA, a non-stimulating negative control for CpG DNA. Furthermore, we used doses of CpG DNA ranging from 10 to 50,000 ng per dose to study the modulation of FVIII-specific memory-B-cell responses in vivo. E17 hemophilic mice were treated with a single intravenous dose of 200 ng FVIII to stimulate the generation of FVIII-specific memory B cells and were subsequently treated with another dose of FVIII that was given together with CpG DNA. We analyzed titers of anti-FVIII antibodies in the circulation of these mice one week after the second dose of FVIII. Previously we had shown that a single dose of 200 ng FVIII, given intravenously to E17 hemophilic mice, stimulates the formation of FVIII-specific memory B cells but is not sufficient to induce anti-FVIII antibodies that would be detectable in the circulation. Our results demonstrate a biphasic effect of CpG DNA on the re-stimulation of FVIII-specific memory B cells and their differentiation into antibody-producing plasma cells. Both in vitro and in vivo studies show that CpG DNA at high doses inhibits the re-stimulation and differentiation of FVIII-specific memory B cells. However, CpG DNA at low doses amplifies these processes. Amplification and inhibition of memory-B-cell responses are due to specific interactions of CpG DNA with TLR 9. Both effects are blocked by addition of a blocking agent for TLR 9 in vitro. We conclude that triggering of TLR 9 by bacterial DNA has a substantial influence on FVIII-specific memory-B-cell responses. The consequence of TLR 9 triggering can be inhibitory or stimulatory, depending on the actual concentration of the bacterial DNA. Our findings demonstrate the potential modulatory effects of bacterial infections on the regulation of FVIII inhibitor development.

scholarly journals Cd5 Maintains Tolerance in Anergic B Cells

2000 ◽  
Vol 191 (5) ◽  
pp. 883-890 ◽  
Author(s):  
Keli L. Hippen ◽  
Lina E. Tze ◽  
Timothy W. Behrens
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Receptor ◽  
Immunoglobulin M ◽  
B Cell Tolerance ◽  
Cell Responses ◽  
B Cell Anergy ◽  
Clonal Anergy

Clonal anergy of autoreactive B cells is a key mechanism regulating tolerance. Here, we show that anergic B cells express significant surface levels of CD5, a molecule normally found on T cells and a subset of B-1 cells. Breeding of the hen egg lysozyme (HEL) transgenic model for B cell anergy onto the CD5 null background resulted in a spontaneous loss of B cell tolerance in vivo. Evidence for this included elevated levels of anti-HEL immunoglobulin M (IgM) antibodies in the serum of CD5−/− mice transgenic for both an HEL-specific B cell receptor (BCR) and soluble lysozyme. “Anergic” B cells lacking CD5 also showed enhanced proliferative responses in vitro and elevated intracellular Ca2+ levels at rest and after IgM cross-linking. These data support the hypothesis that CD5 negatively regulates Ig receptor signaling in anergic B cells and functions to inhibit autoimmune B cell responses.

scholarly journals Ligation of CD27 on B Cells In Vivo during Primary Immunization Enhances Commitment to Memory B Cell Responses

2003 ◽  
Vol 171 (11) ◽  
pp. 5876-5881 ◽  
Author(s):  
Vanitha S. Raman ◽  
Rama S. Akondy ◽  
Satyajit Rath ◽  
Vineeta Bal ◽  
Anna George
Keyword(s):  
B Cells ◽  
B Cell ◽  
Primary Immunization ◽  
Memory B Cell ◽  
Cell Responses ◽  
B Cell Responses

scholarly journals Exposure of a Distinct PDCA-1+ (CD317) B Cell Population to Agonistic Anti-4-1BB (CD137) Inhibits T and B Cell Responses Both In Vitro and In Vivo

PLoS ONE ◽  
2012 ◽  
Vol 7 (11) ◽  
pp. e50272 ◽  
Author(s):  
Dass S. Vinay ◽  
Seung J. Lee ◽  
Chang H. Kim ◽  
Ho Sik Oh ◽  
Byoung S. Kwon
Keyword(s):  
B Cell ◽  
Cell Population ◽  
Cell Responses ◽  
B Cell Responses

Prediction of MHC Class I-Restricted Immunogenic Epitopes of B-Cell Receptors Indicates T Cell-Mediated Immunosurveillance of Malignant B Cell Clones.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1949-1949
Author(s):  
Anna-Maria Strothmeyer ◽  
Marcus Duehren-von Minden ◽  
Marcelo A Navarrete ◽  
Kristina Heining-Mikesch ◽  
Hendrik Veelken
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Mhc Class I ◽  
Cell Activity ◽  
Class I ◽  
Cell Responses ◽  
Hla Haplotypes

Abstract Abstract 1949 Poster Board I-972 Tumor-specific immune responses can be induced in patients with indolent B cell lymphomas (iNHL) by active immunization against the individual B cell receptor (BCR) expressed by the malignant B cell clone, the so-called “idiotype” (Id). In subsequent trials of intradermal vaccination with recombinant lymphoma-derived Fab fragment in iNHL, we have studied the specificity of MHC class I-restricted anti-Id T cell responses by epitope mapping experiments with synthetic Id-derived peptides predicted to be presented by the respective patient's HLA complex. While such peptides exist in hypervariable and conserved Id regions, these assays have shown consistently that in vivo-induced T cell responses occur preferentially against individual Id epitopes located in complementarity-determining regions (CDR), whereas framework (FR) and constant region-derived epitopes are ignored (Bertinetti et al., Cancer Res. 2006; Navarrete et al., ASH 2008). These results contrast with in vitro studies showing that FR-derived peptides are excellent targets for cytotoxic T cells in iNHL patients (Trojan et al., Nat Med 2000). To gain further insight into the relative predominance and immunological role of MHC class I-restricted Id epitopes, we conducted a comprehensive reverse immunology study in follicular lymphoma (FL). Clonal and functional IgH chain transcript sequences were identified from tumor biopsies of 39 FL patients by A-PCR (Bertinetti et al., EJH 2006). The HLA-A and B haplotype of the patients was determined by conventional serological testing and high-resolution PCR genotyping. Potentially MHC-presentable peptides from all Id sequences and their corresponding germ-line (GL) VH genes were identified for the HLA haplotypes of all 39 patients by reverse immunology (bimas.cit.nih.gov). Identified peptides were ranked for each haplotype according to their predicted score, and the sum of the scores for the 20 highest ranking peptides was calculated. The sum score for any given Id was compared to the mean of the sum scores of the other 38 Ids on the respective patient's HLA haplotypes. Separate analyses were performed for CDR peptides (containing at least 2 AA in any CDR) versus non-CDR-peptides (allocated through imgt.cines.fr), Id versus GL sequences, and Id versus contaminating sporadic Ig sequences that represent bona fide normal B cells in the biopsies. 72% of all peptides with BIMAS scores of ≥50 and ≥10, respectively, were located in FR, expecially in FR3. The ranked sum Id scores were lower for the patients' own tumor Id than for the mean of the allogeneic Ids (Table; Wilcoxon's matched pair test). This difference was mostly attributable to CDR-derived epitopes throughout all CDRs despite overall lower immunogenicity compared to FR. There was no evidence for differential immunogenicity between a hypermutated FL Id and the corresponding GL (p=0.58). Finally, a preliminary survey of IgH sequences from non-clonal B cells indicated similar immunogenicity compared to FL Id (p=0.31). These bioinformatic findings indicate T cell-mediated immunosurveillance against the BCR of malignant and perhaps nonmalignant B cells. T cell activity appears to be directed predominantly against individual CDR peptides despite their lesser predicted HLA binding capacity compared to FR peptides. Existing CDR epitopes are not generated during the hypermutation process of BCRs, raising the possibility that randomly generated, more immunogenic hypervariable peptides are not permitted by the immune system. In conjunction with the T cell activity observed in in vivo and in vitro studies cited above, these findings are consistent with strong peripheral tolerance to shared Id structures. On the other hand, T cell control of individual Id peptides may play a role in immunosurveillance of malignant B cells and may be exploited for active immunotherapy of lymphoma. In contrast, generic or pan-B-cell epitopes are predicted to be less effective in inducing anti-lymphoma T cell responses.Median (range) BIMASPatient IdMean of allogeneic IdscomparisonAll peptides213 (40-5920)369 (56-5520)p=0.0012FR peptides157 (20-5415)239 (18-3891)p=0.045CDR peptides74 (7-648)175 (21-1760)p<0.0001- CDR1 peptides21 (0.7-144)52 (1.9-630)p=0.0007- CDR2 peptides7.6 (0.2-345)30 (2.2-212)p=0.0089- CDR3 peptides16 (1.3-506)37 (6-980)p=0.0008 Disclosures: No relevant conflicts of interest to declare.

scholarly journals The E3 ubiquitin ligase Itch restricts antigen-driven B cell responses

2019 ◽  
Vol 216 (9) ◽  
pp. 2170-2183 ◽  
Author(s):  
Emily K. Moser ◽  
Jennifer Roof ◽  
Joseph M. Dybas ◽  
Lynn A. Spruce ◽  
Steven H. Seeholzer ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Fate ◽  
Ubiquitin Ligase ◽  
Cell Activity ◽  
E3 Ubiquitin Ligase ◽  
Normal Numbers ◽  
Cell Responses ◽  
B Cell Responses

The E3 ubiquitin ligase Itch regulates antibody levels and prevents autoimmune disease in humans and mice, yet how Itch regulates B cell fate or function is unknown. We now show that Itch directly limits B cell activity. While Itch-deficient mice displayed normal numbers of preimmune B cell populations, they showed elevated numbers of antigen-experienced B cells. Mixed bone marrow chimeras revealed that Itch acts within B cells to limit naive and, to a greater extent, germinal center (GC) B cell numbers. B cells lacking Itch exhibited increased proliferation, glycolytic capacity, and mTORC1 activation. Moreover, stimulation of these cells in vivo by WT T cells resulted in elevated numbers of GC B cells, PCs, and serum IgG. These results support a novel role for Itch in limiting B cell metabolism and proliferation to suppress antigen-driven B cell responses.

scholarly journals Inhibition of Stearoyl-CoA desaturase suppresses follicular help T and germinal center B cell responses

2019 ◽  
Author(s):  
Young Min Son ◽  
In Su Cheon ◽  
Nick P. Goplen ◽  
Alexander L. Dent ◽  
Jie Sun
Keyword(s):  
Fatty Acid ◽  
B Cell ◽  
Germinal Center ◽  
Monounsaturated Fatty Acids ◽  
Cell Responses ◽  
Follicular Helper ◽  
Germinal Center B Cell ◽  
B Cell Responses

AbstractStearoyl-CoA desaturases (SCD) are endoplasmic reticulum (ER) associated enzymes that catalyze the synthesis of the monounsaturated fatty acids (MUFAs). As such, SCD play important roles in maintaining the intracellular balance between saturated fatty acid (SFAs) and MUFAs. The roles of SCD in CD4+ T helper cell responses are currently unexplored. Here, we have found that murine and human follicular helper T (TFH) cells express higher levels of SCD1 compared to non-TFH cells. Further, the expression of SCD1 in TFH cells is dependent on the TFH lineage-specification transcription factor BCL6. We found that the inhibition of SCD1 impaired TFH cell maintenance and shifted the balance between TFH and follicular regulatory T (TFR) cells in the spleen. Consequently, SCD1 inhibition dampened germinal center B cell responses following influenza immunization. Mechanistically, we found that SCD inhibition led to increased ER stress and enhanced TFH cell apoptosis in vitro and in vivo. These results reveal a possible link between fatty acid metabolism and cellular and humoral responses induced by immunization or potentially, autoimmunity.

scholarly journals B cell–intrinsic signaling through IL-21 receptor and STAT3 is required for establishing long-lived antibody responses in humans

2010 ◽  
Vol 207 (1) ◽  
pp. 155-171 ◽  
Author(s):  
Danielle T. Avery ◽  
Elissa K. Deenick ◽  
Cindy S. Ma ◽  
Santi Suryani ◽  
Nicholas Simpson ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Plasma Cells ◽  
Cell Function ◽  
Critical Role ◽  
Cell Formation ◽  
Janus Kinase ◽  
B Cell Differentiation

Engagement of cytokine receptors by specific ligands activate Janus kinase–signal transducer and activator of transcription (STAT) signaling pathways. The exact roles of STATs in human lymphocyte behavior remain incompletely defined. Interleukin (IL)-21 activates STAT1 and STAT3 and has emerged as a potent regulator of B cell differentiation. We have studied patients with inactivating mutations in STAT1 or STAT3 to dissect their contribution to B cell function in vivo and in response to IL-21 in vitro. STAT3 mutations dramatically reduced the number of functional, antigen (Ag)-specific memory B cells and abolished the ability of IL-21 to induce naive B cells to differentiate into plasma cells (PCs). This resulted from impaired activation of the molecular machinery required for PC generation. In contrast, STAT1 deficiency had no effect on memory B cell formation in vivo or IL-21–induced immunoglobulin secretion in vitro. Thus, STAT3 plays a critical role in generating effector B cells from naive precursors in humans. STAT3-activating cytokines such as IL-21 thus underpin Ag-specific humoral immune responses and provide a mechanism for the functional antibody deficit in STAT3-deficient patients.

scholarly journals B Cell Responses to CpG Correlate with CXCL16 Expression Levels in Common Variable Immunodeficiency

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Vassilios Lougaris ◽  
Manuela Baronio ◽  
Massimiliano Vitali ◽  
Giacomo Tampella ◽  
Annarosa Soresina ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Common Variable Immunodeficiency ◽  
Expression Levels ◽  
Cell Responses ◽  
Surface Receptor ◽  
B Cell Responses ◽  
And Function ◽  
Common Variable

Broad Toll-like receptor 9 (TLR9) signalling defects after CpGin vitrostimulation have been described in common variable immunodeficiency (CVID). CXCL16, a surface receptor, was recently shown to influence cell responses to CpG. We evaluated the expression and function of CXCL16 on B cells from healthy controls and CVID patients. We report that CXCL16 is normally expressed on B cells throughout peripheral maturation. Decreased B cell expression of CXCL16 was observed in a subgroup of CVID patients that correlated with defectivein vitroresponses to CpG (such as upregulation of CD69, CD86, AICDA, IL-6, and TLR9). Our data suggest that expression levels of a surface receptor, namely, CXCL16, correlate with B cell responses mediated by TLR9 in common variable immunodeficiency.

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