T cell hybridomas to study MHC-II restricted B-cell receptor-mediated antigen presentation by human B cells

Epstein–Barr virus (EBV) infects human B cells and reprograms them to allow virus replication and persistence. One key viral factor in this process is latent membrane protein 2A (LMP2A), which has been described as a B cell receptor (BCR) mimic promoting malignant transformation. However, how LMP2A signaling contributes to tumorigenesis remains elusive. By comparing LMP2A and BCR signaling in primary human B cells using phosphoproteomics and transcriptome profiling, we identified molecular mechanisms through which LMP2A affects B cell biology. Consistent with the literature, we found that LMP2A mimics a subset of BCR signaling events, including tyrosine phosphorylation of the kinase SYK, the calcium initiation complex consisting of BLNK, BTK, and PLCγ2, and its downstream transcription factor NFAT. However, the majority of LMP2A-induced signaling events markedly differed from those induced by BCR stimulation. These included differential phosphorylation of kinases, phosphatases, adaptor proteins, transcription factors such as nuclear factor κB (NF-κB) and TCF3, as well as widespread changes in the transcriptional output of LMP2A-expressing B cells. LMP2A affected apoptosis and cell-cycle checkpoints by dysregulating the expression of apoptosis regulators such as BCl-xL and the tumor suppressor retinoblastoma-associated protein 1 (RB1). LMP2A cooperated with MYC and mutant cyclin D3, two oncogenic drivers of Burkitt lymphoma, to promote proliferation and survival of primary human B cells by counteracting MYC-induced apoptosis and by inhibiting RB1 function, thereby promoting cell-cycle progression. Our results indicate that LMP2A is not a pure BCR mimic but rather rewires intracellular signaling in EBV-infected B cells that optimizes cell survival and proliferation, setting the stage for oncogenic transformation.

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B-cell-activating factor inhibits CD20-mediated and B-cell receptor-mediated apoptosis in human B cells

Immunology ◽

10.1111/j.1365-2567.2008.02872.x ◽

2008 ◽

Vol 125 (4) ◽

pp. 570-590 ◽

Cited By ~ 18

Author(s):

Yohei Saito ◽

Yoshitaka Miyagawa ◽

Keiko Onda ◽

Hideki Nakajima ◽

Ban Sato ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Cell Receptor ◽

B Cell Receptor ◽

B Cell Activating Factor ◽

Human B Cells

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Globotriaosyl ceramide (CD77/Gb3) in the glycolipid-enriched membrane domain participates in B-cell receptor–mediated apoptosis by regulating Lyn kinase activity in human B cells

Experimental Hematology ◽

10.1016/s0301-472x(00)00538-5 ◽

2000 ◽

Vol 28 (11) ◽

pp. 1260-1268 ◽

Cited By ~ 56

Author(s):

T Mori

Keyword(s):

B Cells ◽

B Cell ◽

Kinase Activity ◽

Cell Receptor ◽

B Cell Receptor ◽

Membrane Domain ◽

Lyn Kinase ◽

Human B Cells ◽

Globotriaosyl Ceramide

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Inhibition of B cell receptor-mediated activation of primary human B cells by coengagement of CD19 and FcγRIIb with Fc-engineered antibodies

Molecular Immunology ◽

10.1016/j.molimm.2008.06.027 ◽

2008 ◽

Vol 45 (15) ◽

pp. 3926-3933 ◽

Cited By ~ 74

Author(s):

Seung Y. Chu ◽

Igor Vostiar ◽

Sher Karki ◽

Gregory L. Moore ◽

Greg A. Lazar ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Cell Receptor ◽

B Cell Receptor ◽

Human B Cells

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Regulation of B cell fate by chronic activity of the IgE B cell receptor

eLife ◽

10.7554/elife.21238 ◽

2016 ◽

Vol 5 ◽

Cited By ~ 34

Author(s):

Zhiyong Yang ◽

Marcus J Robinson ◽

Xiangjun Chen ◽

Geoffrey A Smith ◽

Jack Taunton ◽

...

Keyword(s):

T Cell ◽

B Cells ◽

B Cell ◽

Cell Fate ◽

Plasma Cells ◽

Cell Receptor ◽

Culture Conditions ◽

B Cell Receptor ◽

Cell Cycles ◽

T Cell Help

IgE can trigger potent allergic responses, yet the mechanisms regulating IgE production are poorly understood. Here we reveal that IgE+ B cells are constrained by chronic activity of the IgE B cell receptor (BCR). In the absence of cognate antigen, the IgE BCR promoted terminal differentiation of B cells into plasma cells (PCs) under cell culture conditions mimicking T cell help. This antigen-independent PC differentiation involved multiple IgE domains and Syk, CD19, BLNK, Btk, and IRF4. Disruption of BCR signaling in mice led to consistently exaggerated IgE+ germinal center (GC) B cell but variably increased PC responses. We were unable to confirm reports that the IgE BCR directly promoted intrinsic apoptosis. Instead, IgE+ GC B cells exhibited poor antigen presentation and prolonged cell cycles, suggesting reduced competition for T cell help. We propose that chronic BCR activity and access to T cell help play critical roles in regulating IgE responses.

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Rapid Emergence of T Follicular Helper and Germinal Center B Cells Following Antiretroviral Therapy in Advanced HIV Disease

Frontiers in Immunology ◽

10.3389/fimmu.2021.752782 ◽

2021 ◽

Vol 12 ◽

Author(s):

Chun-Shu Wong ◽

Clarisa M. Buckner ◽

Silvia Lucena Lage ◽

Luxin Pei ◽

Felipe L. Assis ◽

...

Keyword(s):

T Cell ◽

B Cells ◽

Antiretroviral Therapy ◽

B Cell ◽

Germinal Center ◽

Cell Receptor ◽

B Cell Receptor ◽

Cd4 T Cell ◽

Follicular Helper ◽

Cell Counts

Low nadir CD4 T-cell counts in HIV+ patients are associated with high morbidity and mortality and lasting immune dysfunction, even after antiretroviral therapy (ART). The early events of immune recovery of T cells and B cells in severely lymphopenic HIV+ patients have not been fully characterized. In a cohort of lymphopenic (CD4 T-cell count < 100/µL) HIV+ patients, we studied mononuclear cells isolated from peripheral blood (PB) and lymph nodes (LN) pre-ART (n = 40) and 6-8 weeks post-ART (n = 30) with evaluation of cellular immunophenotypes; histology on LN sections; functionality of circulating T follicular helper (cTfh) cells; transcriptional and B-cell receptor profile on unfractionated LN and PB samples; and plasma biomarker measurements. A group of 19 healthy controls (HC, n = 19) was used as a comparator. T-cell and B-cell lymphopenia was present in PB pre-ART in HIV+ patients. CD4:CD8 and CD4 T- and B-cell PB subsets partly normalized compared to HC post-ART as viral load decreased. Strikingly in LN, ART led to a rapid decrease in interferon signaling pathways and an increase in Tfh, germinal center and IgD-CD27- B cells, consistent with histological findings of post-ART follicular hyperplasia. However, there was evidence of cTfh cells with decreased helper capacity and of limited B-cell receptor diversification post-ART. In conclusion, we found early signs of immune reconstitution, evidenced by a surge in LN germinal center cells, albeit limited in functionality, in HIV+ patients who initiate ART late in disease.

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Fc gammaRIIb inhibits both B cell receptor- and CD19-induced Ca2+ mobilization in Fc gammaR-transfected human B cells.

International Immunology ◽

10.1093/intimm/10.2.141 ◽

1998 ◽

Vol 10 (2) ◽

pp. 141-146 ◽

Cited By ~ 16

Author(s):

G. Koncz ◽

J. Gergely ◽

G. Sarmay

Keyword(s):

B Cells ◽

B Cell ◽

Cell Receptor ◽

B Cell Receptor ◽

Human B Cells

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A critical role of TAK1 in B-cell receptor–mediated nuclear factor κB activation

Blood ◽

10.1182/blood-2008-08-176057 ◽

2009 ◽

Vol 113 (19) ◽

pp. 4566-4574 ◽

Cited By ~ 57

Author(s):

James Schuman ◽

Yuhong Chen ◽

Andrew Podd ◽

Mei Yu ◽

Hong-Hsing Liu ◽

...

Keyword(s):

T Cell ◽

B Cells ◽

B Cell ◽

Critical Role ◽

Cell Receptor ◽

Nuclear Factor Κb ◽

Cell Development ◽

B Cell Receptor ◽

Nuclear Factor

Abstract The kinase TAK1 is essential for T-cell receptor (TCR)–mediated nuclear factor κB (NF-κB) activation and T-cell development. However, the role of TAK1 in B-cell receptor (BCR)–mediated NF-κB activation and B-cell development is not clear. Here we show that B-cell–specific deletion of TAK1 impaired the transition from transitional type 2 to mature follicular (FO) B cells and caused a marked decrease of marginal zone (MZ) B cells. TAK1-deficient B cells exhibited an increase of BCR-induced apoptosis and impaired proliferation in response to BCR ligation. Importantly, TAK1-deficient B cells failed to activate NF-κB after BCR stimulation. Thus, TAK1 is critical for B-cell maturation and BCR-induced NF-κB activation.

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