Resting Human Memory B Cells Are Intrinsically Programmed for Enhanced Survival and Responsiveness to Diverse Stimuli Compared to Naive B Cells

Our knowledge about the clonal composition and intraclonal diversity of the human memory B-cell compartment and the relationship between memory B-cell subsets is still limited, although these are central issues for our understanding of adaptive immunity. We performed a deep sequencing analysis of rearranged immunoglobulin (Ig) heavy chain genes from biological replicates, covering more than 100,000 memory B lymphocytes from two healthy adults. We reveal a highly similar B-cell receptor repertoire among the four main human IgM+ and IgG+ memory B-cell subsets. Strikingly, in both donors, 45% of sequences could be assigned to expanded clones, demonstrating that the human memory B-cell compartment is characterized by many, often very large, B-cell clones. Twenty percent of the clones consisted of class switched and IgM+(IgD+) members, a feature that correlated significantly with clone size. Hence, we provide strong evidence that the vast majority of Ig mutated B cells—including IgM+IgD+CD27+ B cells—are post-germinal center (GC) memory B cells. Clone members showed high intraclonal sequence diversity and high intraclonal versatility in Ig class and IgG subclass composition, with particular patterns of memory B-cell clone generation in GC reactions. In conclusion, GC produce amazingly large, complex, and diverse memory B-cell clones, equipping the human immune system with a versatile and highly diverse compartment of IgM+(IgD+) and class-switched memory B cells.

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Integrative transcriptome and chromatin landscape analysis reveals distinct epigenetic regulations in human memory B cells

Nature Communications ◽

10.1038/s41467-020-19242-6 ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Justin B. Moroney ◽

Anusha Vasudev ◽

Alexander Pertsemlidis ◽

Hong Zan ◽

Paolo Casali

Keyword(s):

B Cells ◽

Target Genes ◽

Human Memory ◽

Regulatory Elements ◽

Chromatin Accessibility ◽

Memory B Cells ◽

Transcriptional Signature ◽

Integrative Analyses ◽

Health And Disease ◽

Variable Gene

Abstract Memory B cells (MBCs) are long-lived and produce high-affinity, generally, class-switched antibodies. Here, we use a multiparameter approach involving CD27 to segregate naïve B cells (NBC), IgD+ unswitched (unsw)MBCs and IgG+ or IgA+ class-switched (sw)MBCs from humans of different age, sex and race. Conserved antibody variable gene expression indicates that MBCs emerge through unbiased selection from NBCs. Integrative analyses of mRNAs, miRNAs, lncRNAs, chromatin accessibility and cis-regulatory elements uncover a core mRNA-ncRNA transcriptional signature shared by IgG+ and IgA+ swMBCs and distinct from NBCs, while unswMBCs display a transitional transcriptome. Some swMBC transcriptional signature loci are accessible but not expressed in NBCs. Profiling miRNAs reveals downregulated MIR181, and concomitantly upregulated MIR181 target genes such as RASSF6, TOX, TRERF1, TRPV3 and RORα, in swMBCs. Finally, lncRNAs differentially expressed in swMBCs cluster proximal to the IgH chain locus on chromosome 14. Our findings thus provide new insights into MBC transcriptional programs and epigenetic regulation, opening new investigative avenues on these critical cell elements in human health and disease.

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A role for Toll-like receptors in acquired immunity: up-regulation of TLR9 by BCR triggering in naive B cells and constitutive expression in memory B cells

Blood ◽

10.1182/blood-2002-11-3569 ◽

2003 ◽

Vol 101 (11) ◽

pp. 4500-4504 ◽

Cited By ~ 463

Author(s):

Nadia L. Bernasconi ◽

Nobuyuki Onai ◽

Antonio Lanzavecchia

Keyword(s):

B Cells ◽

B Cell ◽

Constitutive Expression ◽

Human Memory ◽

Cell Receptor ◽

Primary Response ◽

Memory B Cells ◽

Toll Like Receptors ◽

Polyclonal Activation ◽

B Cell Subsets

Abstract Toll-like receptors (TLRs) are pattern recognition receptors that trigger innate immunity. In this study we investigated the expression of 10 TLRs in human naive and memory B-cell subsets. We report that in human naive B cells most TLRs are expressed at low to undetectable levels, but the expression of TLR9 and TLR10 is rapidly induced following B-cell-receptor (BCR) triggering. In contrast, memory B cells express several TLRs at constitutively high levels. The differential expression of TLR9 correlates with responsiveness to its agonist, CpG DNA. Thus, human memory B cells proliferate and differentiate to immunoglobulin (Ig)–secreting cells in response to CpG, while naive B do so only if simultaneously triggered through the BCR. The BCR-induced expression of TLRs in human naive B cells prevents polyclonal activation in a primary response, because it restricts stimulation to antigen-specific B cells. In contrast, the constitutive expression of TLRs in memory B cells allows polyclonal activation of the entire memory pool. Thus, in human B cells TLRs are downstream of BCR and play a role both in the primary response and in the memory phase.

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Human memory B cells originate from three distinct germinal center-dependent and -independent maturation pathways

Blood ◽

10.1182/blood-2011-04-345579 ◽

2011 ◽

Vol 118 (8) ◽

pp. 2150-2158 ◽

Cited By ~ 217

Author(s):

Magdalena A. Berkowska ◽

Gertjan J. A. Driessen ◽

Vasilis Bikos ◽

Christina Grosserichter-Wagener ◽

Kostas Stamatopoulos ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Germinal Center ◽

Somatic Hypermutation ◽

Phenotypic Diversity ◽

Human Memory ◽

Memory B Cells ◽

Memory B Cell ◽

Effector Cells ◽

B Cell Subsets

Abstract Multiple distinct memory B-cell subsets have been identified in humans, but it remains unclear how their phenotypic diversity corresponds to the type of responses from which they originate. Especially, the contribution of germinal center-independent responses in humans remains controversial. We defined 6 memory B-cell subsets based on their antigen-experienced phenotype and differential expression of CD27 and IgH isotypes. Molecular characterization of their replication history, Ig somatic hypermutation, and class-switch profiles demonstrated their origin from 3 different pathways. CD27−IgG+ and CD27+IgM+ B cells are derived from primary germinal center reactions, and CD27+IgA+ and CD27+IgG+ B cells are from consecutive germinal center responses (pathway 1). In contrast, natural effector and CD27−IgA+ memory B cells have limited proliferation and are also present in CD40L-deficient patients, reflecting a germinal center-independent origin. Natural effector cells at least in part originate from systemic responses in the splenic marginal zone (pathway 2). CD27−IgA+ cells share low replication history and dominant Igλ and IgA2 use with gut lamina propria IgA+ B cells, suggesting their common origin from local germinal center-independent responses (pathway 3). Our findings shed light on human germinal center-dependent and -independent B-cell memory formation and provide new opportunities to study these processes in immunologic diseases.

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The Majority of Human Memory B Cells Recognizing RhD and Tetanus Resides in IgM+B Cells

The Journal of Immunology ◽

10.4049/jimmunol.1400706 ◽

2014 ◽

Vol 193 (3) ◽

pp. 1071-1079 ◽

Cited By ~ 21

Author(s):

Luciana Della Valle ◽

Serge E. Dohmen ◽

Onno J. H. M. Verhagen ◽

Magdalena A. Berkowska ◽

Gestur Vidarsson ◽

...

Keyword(s):

B Cells ◽

Human Memory ◽

Memory B Cells

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Optimisation of ex vivo memory B cell expansion/differentiation for interrogation of rare peripheral memory B cell subset responses

Wellcome Open Research ◽

10.12688/wellcomeopenres.11386.2 ◽

2018 ◽

Vol 2 ◽

pp. 97 ◽

Cited By ~ 1

Author(s):

Luke Muir ◽

Paul F. McKay ◽

Velislava N. Petrova ◽

Oleksiy V. Klymenko ◽

Sven Kratochvil ◽

...

Keyword(s):

Cell Culture ◽

B Cells ◽

B Cell ◽

Cell Expansion ◽

Ex Vivo ◽

Cell Subset ◽

Human Memory ◽

Memory B Cells ◽

Memory B Cell ◽

B Cell Subsets

Background:Human memory B cells play a vital role in the long-term protection of the host from pathogenic re-challenge. In recent years the importance of a number of different memory B cell subsets that can be formed in response to vaccination or infection has started to become clear. To study memory B cell responses, cells can be culturedex vivo,allowing for an increase in cell number and activation of these quiescent cells, providing sufficient quantities of each memory subset to enable full investigation of functionality. However, despite numerous papers being published demonstrating bulk memory B cell culture, we could find no literature on optimised conditions for the study of memory B cell subsets, such as IgM+memory B cells.Methods:Following a literature review, we carried out a large screen of memory B cell expansion conditions to identify the combination that induced the highest levels of memory B cell expansion. We subsequently used a novel Design of Experiments approach to finely tune the optimal memory B cell expansion and differentiation conditions for human memory B cell subsets. Finally, we characterised the resultant memory B cell subpopulations by IgH sequencing and flow cytometry.Results:The application of specific optimised conditions induce multiple rounds of memory B cell proliferation equally across Ig isotypes, differentiation of memory B cells to antibody secreting cells, and importantly do not alter the Ig genotype of the stimulated cells. Conclusions:Overall, our data identify a memory B cell culture system that offers a robust platform for investigating the functionality of rare memory B cell subsets to infection and/or vaccination.

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BAFF selectively enhances the survival of plasmablasts generated from human memory B cells

Journal of Clinical Investigation ◽

10.1172/jci200318025c ◽

2004 ◽

Vol 113 (7) ◽

pp. 1069-1069

Author(s):

D. T. Avery

Keyword(s):

B Cells ◽

Human Memory ◽

Memory B Cells

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Fc receptor-like 4 and 5 define human atypical memory B cells

International Immunology ◽

10.1093/intimm/dxaa053 ◽

2020 ◽

Vol 32 (12) ◽

pp. 755-770

Author(s):

Huifang Li ◽

Jessica Dement-Brown ◽

Pei-Jyun Liao ◽

Ilya Mazo ◽

Frederick Mills ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Human Memory ◽

Memory B Cells ◽

Surface Proteins ◽

Quiescent State ◽

Memory Cells ◽

Lineage Trees ◽

Memory Subset

Abstract Atypical memory B cells accumulate in chronic infections and autoimmune conditions, and commonly express FCRL4 and FCRL5, respective IgA and IgG receptors. We characterized memory cells from tonsils on the basis of both FCRL4 and FCRL5 expression, defining three subsets with distinct surface proteins and gene expression. Atypical FCRL4+FCRL5+ memory cells had the most discrete surface protein expression and were enriched in cell adhesion pathways, consistent with functioning as tissue-resident cells. Atypical FCRL4−FCRL5+ memory cells expressed transcription factors and immunoglobulin genes that suggest poised differentiation into plasma cells. Accordingly, the FCRL4−FCRL5+ memory subset was enriched in pathways responding to endoplasmic reticulum stress and IFN-γ. We reconstructed ongoing B-cell responses as lineage trees, providing crucial in vivo developmental context. Each memory subset typically maintained its lineage, denoting mechanisms enforcing their phenotypes. Classical FCRL4−FCRL5− memory cells were infrequently detected in lineage trees, suggesting the majority were in a quiescent state. FCRL4−FCRL5+ cells were the most represented memory subset in lineage trees, indicating robust participation in ongoing responses. Together, these differences suggest FCRL4 and FCRL5 are unlikely to be passive markers but rather active drivers of human memory B-cell development and function.

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