scholarly journals The quantity of CD40 signaling determines the differentiation of B cells into functionally distinct memory cell subsets

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Takuya Koike ◽  
Koshi Harada ◽  
Shu Horiuchi ◽  
Daisuke Kitamura

In mice, memory B (Bmem) cells can be divided into two subpopulations: CD80hi Bmem cells, which preferentially differentiate into plasma cells; and CD80lo Bmem cells, which become germinal center (GC) B cells during a recall response. We demonstrate that these distinct responses can be B-cell-intrinsic and essentially independent of B-cell receptor (BCR) isotypes. Furthermore, we find that the development of CD80hi Bmem cells in the primary immune response requires follicular helper T cells, a relatively strong CD40 signal and a high-affinity BCR on B cells, whereas the development of CD80lo Bmem cells does not. Quantitative differences in CD40 stimulation were enough to recapitulate the distinct B cell fate decisions in an in vitro culture system. The quantity of CD40 signaling appears to be translated into NF-κB activation, followed by BATF upregulation that promotes Bmem cell differentiation from GC B cells.

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Zhiyong Yang ◽  
Marcus J Robinson ◽  
Xiangjun Chen ◽  
Geoffrey A Smith ◽  
Jack Taunton ◽  
...  

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.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Mark Noviski ◽  
James L Mueller ◽  
Anne Satterthwaite ◽  
Lee Ann Garrett-Sinha ◽  
Frank Brombacher ◽  
...  

Naive B cells co-express two BCR isotypes, IgM and IgD, with identical antigen-binding domains but distinct constant regions. IgM but not IgD is downregulated on autoreactive B cells. Because these isotypes are presumed to be redundant, it is unknown how this could impose tolerance. We introduced the Nur77-eGFP reporter of BCR signaling into mice that express each BCR isotype alone. Despite signaling strongly in vitro, IgD is less sensitive than IgM to endogenous antigen in vivo and developmental fate decisions are skewed accordingly. IgD-only Lyn−/− B cells cannot generate autoantibodies and short-lived plasma cells (SLPCs) in vivo, a fate thought to be driven by intense BCR signaling induced by endogenous antigens. Similarly, IgD-only B cells generate normal germinal center, but impaired IgG1+ SLPC responses to T-dependent immunization. We propose a role for IgD in maintaining the quiescence of autoreactive B cells and restricting their differentiation into autoantibody secreting cells.


2008 ◽  
Vol 205 (10) ◽  
pp. 2437-2448 ◽  
Author(s):  
Sun Jung Kim ◽  
Michele Caton ◽  
Chuansheng Wang ◽  
Magi Khalil ◽  
Zhi-Jie Zhou ◽  
...  

B cells activated by antigen in T cell–dependent immune responses can become short-lived plasma cells, which remain in the spleen, or germinal center–derived memory or plasma cells, which show evidence of affinity maturation and, in the case of plasma cells, migrate to the bone marrow. We show that this cell fate decision can be governed by the cytokine environment engendered by activated dendritic cells (DCs). DCs from mice lacking the Fc receptor γ chain exhibited an activated phenotype in vitro. They secreted more of the proinflammatory cytokine IL-12, which led to the preferential generation of short-lived splenic plasma cells, with ensuing low affinity antibodies and a diminished recall response. Understanding the factors that regulate antigen-activated B cell differentiation and memory cell formation has implications for both antibody-mediated autoimmune disease and protective antibody responses.


2016 ◽  
Vol 214 (1) ◽  
pp. 197-208 ◽  
Author(s):  
Bharat Vaidyanathan ◽  
Ashutosh Chaudhry ◽  
William T. Yewdell ◽  
Davide Angeletti ◽  
Wei-Feng Yen ◽  
...  

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.


2019 ◽  
Author(s):  
Muhammad Assad Aslam ◽  
Mir Farshid Alemdehy ◽  
Eliza Mari Kwesi-Maliepaard ◽  
Marieta Caganova ◽  
Iris N. Pardieck ◽  
...  

AbstractDifferentiation of naïve peripheral B cells into terminally differentiated plasma cells is characterized by epigenetic alterations, yet the epigenetic mechanisms that control B cell fate remain unclear. Here we identified a central role for the histone H3K79 methyltransferase DOT1L in controlling B cell differentiation. Murine B cells lacking Dot1L failed to establish germinal centers (GC) and normal humoral immune responses in vivo. In vitro, activated B cells showed aberrant differentiation and prematurely acquired plasma cell features. Mechanistically, combined epigenomics and transcriptomics analysis revealed that DOT1L promotes expression of a pro-proliferative, pro-GC program. In addition, DOT1L supports the repression of an anti-proliferative, plasma cell differentiation program by maintaining expression of the H3K27 methyltransferase Ezh2, the catalytic component of Polycomb Repressor Complex 2 (PRC2). Our findings show that DOT1L is a central modulator of the core transcriptional and epigenetic landscape in B cells, establishing an epigenetic barrier that warrants B cell naivety and GC B cell differentiation.


2019 ◽  
Vol 2 (6) ◽  
pp. e201900506 ◽  
Author(s):  
Zilu Zhu ◽  
Ashima Shukla ◽  
Parham Ramezani-Rad ◽  
John R Apgar ◽  
Robert C Rickert

The PI3K pathway is integral for the germinal center (GC) response. However, the contribution of protein kinase B (AKT) as a PI3K effector in GC B cells remains unknown. Here, we show that mice lacking the AKT1 and AKT2 isoforms in B cells failed to form GCs, which undermined affinity maturation and antibody production in response to immunization. Upon B-cell receptor stimulation, AKT1/2–deficient B cells showed poor survival, reduced proliferation, and impaired mitochondrial and metabolic fitness, which collectively halted GC development. By comparison, Foxo1T24A mutant, which cannot be inactivated by AKT1/2 phosphorylation and is sequestered in the nucleus, significantly enhanced antibody class switch recombination via induction of activation-induced cytidine deaminase (AID) expression. By contrast, repression of FOXO1 activity by AKT1/2 promoted IRF4-driven plasma cell differentiation. Last, we show that T-cell help via CD40, but not enforced expression of Bcl2, rescued the defective GC response in AKT1/2–deficient animals by restoring proliferative expansion and energy production. Overall, our study provides mechanistic insights into the key role of AKT and downstream pathways on B cell fate decisions during the GC response.


Author(s):  
Simon Mitchell

B-cells are the poster child for cellular diversity and heterogeneity. The diverse repertoire of B lymphocytes, each expressing unique antigen receptors, provides broad protection against pathogens. However, B-cell diversity goes beyond unique antigen receptors. Side-stepping B-cell receptor (BCR) diversity through BCR-independent stimuli or engineered organisms with monoclonal BCRs still results in seemingly identical B-cells reaching a wide variety of fates in response to the same challenge. Identifying to what extent the molecular state of a B-cell determines its fate is key to gaining a predictive understanding of B-cells and consequently the ability to control them with targeted therapies. Signals received by B-cells through transmembrane receptors converge on intracellular molecular signaling networks, which control whether each B-cell divides, dies, or differentiates into a number of antibody-secreting distinct B-cell subtypes. The signaling networks that interpret these signals are well known to be susceptible to molecular variability and noise, providing a potential source of diversity in cell fate decisions. Iterative mathematical modeling and experimental studies have provided quantitative insight into how B-cells achieve distinct fates in response to pathogenic stimuli. Here, we review how systems biology modeling of B-cells, and the molecular signaling networks controlling their fates, is revealing the key determinants of cell-to-cell variability in B-cell destiny.


Blood ◽  
2002 ◽  
Vol 99 (2) ◽  
pp. 567-575 ◽  
Author(s):  
Haruo Nagumo ◽  
Kazunaga Agematsu ◽  
Norimoto Kobayashi ◽  
Koji Shinozaki ◽  
Sho Hokibara ◽  
...  

Abstract The relationship between class switch recombination (CSR) and somatic hypermutation has been unclear. By using human CD27− naive B cells, we investigated the somatic hypermutation and producibility of immunoglobulins (Igs) that occur after CSR. Although neither adult CD27− nor cord blood B cells, which showed the unmutated Ig V-region genes, produced IgG, IgM, or IgA in response to conventional stimuli, they produced IgG and IgM but not IgA in the presence of Staphylococcus aureus Cowan strain (SAC) + interleukin-2 (IL-2) + IL-10 + anti-CD40 mAb + CD32 transfectants (CD40/CD32T). The naive B cells also produced IgE when combined with IL-4 + CD40/CD32T. In parallel with IgG production, the expression of mature γ1 and γ 2 transcripts was induced from naive B cells by the stimuli. The CD27 expression on human naive B cells was induced remarkably by CD40 signaling or B-cell receptor engagement, but somatic hypermutation could not be induced. The proliferation and differentiation into plasma cells were induced from naive B cells, whereas most of the plasma cells displayed very low levels of mutations in Ig V-region genes. CD27− naive B cells expressed activation-induced cytidine deaminase messenger RNA by the stimuli later than CD27+memory B cells. Our results demonstrate that CSR, but not noticeable somatic hypermutation, can be induced from CD27− naive B cells upon B-cell receptor engagement and CD40 signaling in cooperation with cytokines, suggesting that CSR and somatic hypermutation processes can occur independently, and the antibodies produced in this in vitro system are low-affinity antibodies.


2015 ◽  
Vol 212 (10) ◽  
pp. 1679-1692 ◽  
Author(s):  
Arnav Mehta ◽  
Mati Mann ◽  
Jimmy L. Zhao ◽  
Georgi K. Marinov ◽  
Devdoot Majumdar ◽  
...  

MicroRNAs have emerged as key regulators of B cell fate decisions and immune function. Deregulation of several microRNAs in B cells leads to the development of autoimmune disease and cancer in mice. We demonstrate that the microRNA-212/132 cluster (miR-212/132) is induced in B cells in response to B cell receptor signaling. Enforced expression of miR-132 results in a block in early B cell development at the prepro–B cell to pro–B cell transition and induces apoptosis in primary bone marrow B cells. Importantly, loss of miR-212/132 results in accelerated B cell recovery after antibody-mediated B cell depletion. We find that Sox4 is a target of miR-132 in B cells. Co-expression of SOX4 with miR-132 rescues the defect in B cell development from overexpression of miR-132 alone, thus suggesting that miR-132 may regulate B lymphopoiesis through Sox4. In addition, we show that the expression of miR-132 can inhibit cancer development in cells that are prone to B cell cancers, such as B cells expressing the c-Myc oncogene. We have thus uncovered miR-132 as a novel contributor to B cell development.


Author(s):  
Liam Kealy ◽  
Kim L Good-Jacobson

Abstract Immunological memory has the potential to provide lifelong protection against recurrent infections. As such, it has been crucial to the success of vaccines. Yet, the recent pandemic has illuminated key gaps in our knowledge related to the factors influencing effective memory formation and the inability to predict the longevity of immune protection. In recent decades, researchers have acquired a number of novel and powerful tools with which to study the factors underpinning humoral memory. These tools have been used to study the B-cell fate decisions that occur within the germinal centre, a site where responding B-cells undergo affinity maturation and is one of the major routes for memory B-cell and high-affinity long-lived plasma cell formation. The advent of single-cell sequencing technology has provided an enhanced resolution for studying fate decisions within the germinal centre and cutting-edge techniques have enabled researchers to model this reaction with more accuracy both in vitro and in silico. Moreover, modern approaches to studying memory B-cells have allowed us to gain a better appreciation for the heterogeneity and adaptability of this vital class of B-cells. Together, these studies have facilitated important breakthroughs in our understanding of how these systems operate to ensure a successful immune response. In this review, we describe recent advances in the field of germinal centre and memory B-cell biology in order to provide insight into how humoral memory is formed, as well as the potential for generating lasting immunity to novel pathogens such as SARS-CoV-2.


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