scholarly journals Mixed Origins: HIV gp120-specific memory develops from pre-existing memory and naive B cells following vaccination in humans

2021 ◽  
Author(s):  
Madhubanti Basu ◽  
Michael S Piepenbrink ◽  
Christopher Fucile ◽  
Catherine A Bunce ◽  
Li-Xing Man ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Somatic Hypermutation ◽  
Vaccine Trial ◽  
Cell Receptor ◽  
Cell Compartment ◽  
Specific Memory ◽  
Hiv Gp120 ◽  
Lineage Tracking ◽  
Hiv Envelope

The most potent and broad HIV envelope (Env)-specific antibodies often when reverted to their inferred germline versions representing the naive B cell receptor, fail to bind Env suggesting that the initial responding B cell population is not exclusively comprised of a naive population, but also a pre-existing cross-reactive antigen-experienced B cell pool that expands following Env exposure. Previously we isolated gp120-reactive monoclonal antibodies (mAbs) from participants in HVTN 105, an HIV vaccine trial. Using deep sequencing VH-lineage tracking we identified several of these mAb lineages in pre-immune peripheral blood. Several of these pre-immune lineages also persisted in the bone marrow, including CD138+ long-lived plasma cell compartment, ~7 months after the final vaccination. The majority of the pre-immune lineage members included IgM, however IgG and IgA members were also prevalent and exhibited somatic hypermutation. These results suggest that vaccine-induced gp120-specific antibody lineages originate from both naive and cross-reactive memory B cells.

scholarly journals Signatures of B Cell Receptor Repertoire Following Pneumocystis Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Han Sun ◽  
Hu-Qin Yang ◽  
Kan Zhai ◽  
Zhao-Hui Tong
Keyword(s):  
B Cells ◽  
B Cell ◽  
Single Cell ◽  
Plasma Cells ◽  
Somatic Hypermutation ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Receptor Repertoire ◽  
Elevated Expression ◽  
Pneumocystis Infection

B cells play vital roles in host defense against Pneumocystis infection. However, the features of the B cell receptor (BCR) repertoire in disease progression remain unclear. Here, we integrated single-cell RNA sequencing and single-cell BCR sequencing of immune cells from mouse lungs in an uninfected state and 1–4 weeks post-infection in order to illustrate the dynamic nature of B cell responses during Pneumocystis infection. We identified continuously increased plasma cells and an elevated ratio of (IgA + IgG) to (IgD + IgM) after infection. Moreover, Pneumocystis infection was associated with an increasing naïve B subset characterized by elevated expression of the transcription factor ATF3. The proportion of clonal expanded cells progressively increased, while BCR diversity decreased. Plasma cells exhibited higher levels of somatic hypermutation than naïve B cells. Biased usage of V(D)J genes was observed, and the usage frequency of IGHV9-3 rose. Overall, these results present a detailed atlas of B cell transcriptional changes and BCR repertoire features in the context of Pneumocystis infection, which provides valuable information for finding diagnostic biomarkers and developing potential immunotherapeutic targets.

scholarly journals B Lymphocyte Chemotaxis Regulated in Association with Microanatomic Localization, Differentiation State, and B Cell Receptor Engagement

1998 ◽  
Vol 187 (5) ◽  
pp. 753-762 ◽  
Author(s):  
Conrad C. Bleul ◽  
Joachim L. Schultze ◽  
Timothy A. Springer
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Lymphocytes ◽  
Messenger Rna ◽  
B Lymphocyte ◽  
Somatic Hypermutation ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Cxc Chemokine

Migration of mature B lymphocytes within secondary lymphoid organs and recirculation between these sites are thought to allow B cells to obtain T cell help, to undergo somatic hypermutation, to differentiate into effector cells, and to home to sites of antibody production. The mechanisms that direct migration of B lymphocytes are unknown, but there is evidence that G protein–coupled receptors, and possibly chemokine receptors, may be involved. Stromal cell– derived factor (SDF)-1α is a CXC chemokine previously characterized as an efficacious chemoattractant for T lymphocytes and monocytes in peripheral blood. Here we show with purified tonsillar B cells that SDF-1α also attracts naive and memory, but not germinal center (GC) B lymphocytes. Furthermore, GC B cells could be converted to respond to SDF-1α by in vitro differentiation into memory B lymphocytes. Conversely, the migratory response in naive and memory B cells was significantly reduced after B cell receptor engagement and CD40 signaling. The receptor for SDF-1, CXC chemokine receptor 4 (CXCR4), was found to be expressed on responsive as well as unresponsive B cell subsets, but was more rapidly downregulated on responsive cells by ligand. Finally, messenger RNA for SDF-1 was detected by in situ hybridization in a layer of cells surrounding the GC. These findings show that responsiveness to the chemoattractant SDF-1α is regulated during B lymphocyte activation, and correlates with positioning of B lymphocytes within a secondary lymphoid organ.

scholarly journals Humans with chronic granulomatous disease maintain humoral immunologic memory despite low frequencies of circulating memory B cells

Blood ◽  
2012 ◽  
Vol 120 (24) ◽  
pp. 4850-4858 ◽  
Author(s):  
Susan Moir ◽  
Suk See De Ravin ◽  
Brian H. Santich ◽  
Jin Young Kim ◽  
Jacqueline G. Posada ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Chronic Granulomatous Disease ◽  
Somatic Hypermutation ◽  
Memory B Cells ◽  
Potential Contribution ◽  
Granulomatous Disease ◽  
Immunologic Memory ◽  
Activation Markers ◽  
Specific Memory

Abstract CD27+ memory B cells are reduced in the blood of patients with chronic granulomatous disease (CGD) for reasons and consequences that remain unclear. Here we confirm not only decreased CD27+ but also IgG+ B cells in the blood of CGD patients compared with healthy donors (HDs). However, among IgG+ B cells, the ratio of CD27− to CD27+ was significantly higher in CGD patients compared with HDs. Similar to conventional memory B cells, CD27−IgG+ B cells of CGD patients expressed activation markers and had undergone somatic hypermutation, albeit at levels lower than their CD27+ counterparts. Functional analyses revealed slight reductions in frequencies of total IgG but not influenza-specific memory B-cell responses, as measured by Elispot in CGD patients compared with HDs. Serum IgG levels and influenza-specific antibodies were also normal in these CGD patients. Finally, we provide evidence that influenza-specific memory B cells can be present within the CD27−IgG+ B-cell compartment. Together, these findings show that, despite reduced circulating CD27+ memory B cells, CGD patients maintain an intact humoral immunologic memory, with potential contribution from CD27− B cells.

scholarly journals Antibody Repertoire Analysis of Tumor-Infiltrating B Cells Reveals Distinct Signatures and Distributions Across Tissues

2021 ◽  
Vol 12 ◽  
Author(s):  
Ligal Aizik ◽  
Yael Dror ◽  
David Taussig ◽  
Adi Barzel ◽  
Yaron Carmi ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
High Throughput Sequencing ◽  
Triple Negative ◽  
Somatic Hypermutation ◽  
Cell Receptor ◽  
Antibody Repertoire ◽  
Class Switch ◽  
Repertoire Analysis

The role of B cells in the tumor microenvironment (TME) has largely been under investigated, and data regarding the antibody repertoire encoded by B cells in the TME and the adjacent lymphoid organs are scarce. Here, we utilized B cell receptor high-throughput sequencing (BCR-Seq) to profile the antibody repertoire signature of tumor-infiltrating lymphocyte B cells (TIL−Bs) in comparison to B cells from three anatomic compartments in a mouse model of triple-negative breast cancer. We found that TIL-Bs exhibit distinct antibody repertoire measures, including high clonal polarization and elevated somatic hypermutation rates, suggesting a local antigen-driven B-cell response. Importantly, TIL-Bs were highly mutated but non-class switched, suggesting that class-switch recombination may be inhibited in the TME. Tracing the distribution of TIL-B clones across various compartments indicated that they migrate to and from the TME. The data thus suggests that antibody repertoire signatures can serve as indicators for identifying tumor-reactive B cells.

scholarly journals Malaria-associated atypical memory B cells exhibit markedly reduced B cell receptor signaling and effector function

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Silvia Portugal ◽  
Christopher M Tipton ◽  
Haewon Sohn ◽  
Younoussou Kone ◽  
Jing Wang ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Viral Infections ◽  
Somatic Hypermutation ◽  
Plasmodium Falciparum Malaria ◽  
Cell Receptor ◽  
Memory B Cells ◽  
B Cell Receptor ◽  
Chronic Infections ◽  
Malaria Exposure

Protective antibodies in Plasmodium falciparum malaria are only acquired after years of repeated infections. Chronic malaria exposure is associated with a large increase in atypical memory B cells (MBCs) that resemble B cells expanded in a variety of persistent viral infections. Understanding the function of atypical MBCs and their relationship to classical MBCs will be critical to developing effective vaccines for malaria and other chronic infections. We show that VH gene repertoires and somatic hypermutation rates of atypical and classical MBCs are indistinguishable indicating a common developmental history. Atypical MBCs express an array of inhibitory receptors and B cell receptor (BCR) signaling is stunted in atypical MBCs resulting in impaired B cell responses including proliferation, cytokine production and antibody secretion. Thus, in response to chronic malaria exposure, atypical MBCs appear to differentiate from classical MBCs becoming refractory to BCR-mediated activation and potentially interfering with the acquisition of malaria immunity.

scholarly journals Ubiquitin-mediated fluctuations in MHC class II facilitate efficient germinal center B cell responses

2016 ◽  
Vol 213 (6) ◽  
pp. 993-1009 ◽  
Author(s):  
Oliver Bannard ◽  
Simon J. McGowan ◽  
Jonatan Ersching ◽  
Satoshi Ishido ◽  
Gabriel D. Victora ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Mhc Class Ii ◽  
Somatic Hypermutation ◽  
Ectopic Expression ◽  
Cell Receptor ◽  
Class Ii ◽  
Affinity Maturation ◽  
Efficiency Of Selection ◽  
T Cell Help

Antibody affinity maturation occurs in germinal centers (GCs) through iterative rounds of somatic hypermutation and selection. Selection involves B cells competing for T cell help based on the amount of antigen they capture and present on their MHC class II (MHCII) proteins. How GC B cells are able to rapidly and repeatedly transition between mutating their B cell receptor genes and then being selected shortly after is not known. We report that MHCII surface levels and degradation are dynamically regulated in GC B cells. Through ectopic expression of a photoconvertible MHCII-mKikGR chimeric gene, we found that individual GC B cells differed in the rates of MHCII protein turnover. Fluctuations in surface MHCII levels were dependent on ubiquitination and the E3 ligase March1. Increases in March1 expression in centroblasts correlated with decreases in surface MHCII levels, whereas CD83 expression in centrocytes helped to stabilize MHCII at that stage. Defects in MHCII ubiquitination caused GC B cells to accumulate greater amounts of a specific peptide–MHCII (pMHCII), suggesting that MHCII turnover facilitates the replacement of old complexes. We propose that pMHCII complexes are periodically targeted for degradation in centroblasts to favor the presentation of recently acquired antigens, thereby promoting the fidelity and efficiency of selection.

scholarly journals TET2 deficiency reprograms the germinal center B cell epigenome and silences genes linked to lymphomagenesis

2020 ◽  
Vol 6 (25) ◽  
pp. eaay5872 ◽  
Author(s):  
Wojciech Rosikiewicz ◽  
Xiaowen Chen ◽  
Pilar M. Dominguez ◽  
Hussein Ghamlouch ◽  
Said Aoufouchi ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Germinal Center ◽  
Somatic Hypermutation ◽  
Cell Receptor ◽  
Regulatory Elements ◽  
Dna Hypermethylation ◽  
Epigenetic Effects ◽  
Germinal Center B Cell ◽  
Epigenetic Pattern

The TET2 DNA hydroxymethyltransferase is frequently disrupted by somatic mutations in diffuse large B cell lymphomas (DLBCLs), a tumor that originates from germinal center (GC) B cells. Here, we show that TET2 deficiency leads to DNA hypermethylation of regulatory elements in GC B cells, associated with silencing of the respective genes. This hypermethylation affects the binding of transcription factors including those involved in exit from the GC reaction and involves pathways such as B cell receptor, antigen presentation, CD40, and others. Normal GC B cells manifest a typical hypomethylation signature, which is caused by AID, the enzyme that mediates somatic hypermutation. However, AID-induced demethylation is markedly impaired in TET2-deficient GC B cells, suggesting that AID epigenetic effects are partially dependent on TET2. Last, we find that TET2 mutant DLBCLs also manifest the aberrant TET2-deficient GC DNA methylation signature, suggesting that this epigenetic pattern is maintained during and contributes to lymphomagenesis.

scholarly journals Enforced Expression of Bcl-2 Selectively Perturbs Negative Selection of Dual Reactive Antibodies

2001 ◽  
Vol 8 (3-4) ◽  
pp. 223-234 ◽  
Author(s):  
Evangelia Notidis ◽  
Shailaja Hande ◽  
Tim Manser
Keyword(s):  
B Cells ◽  
B Cell ◽  
Negative Selection ◽  
Somatic Hypermutation ◽  
Serum Antibody ◽  
Affinity Maturation ◽  
Peripheral Tolerance ◽  
Cell Compartment ◽  
Memory B Cell ◽  
Selection Of

We investigated the role of apoptosis in the development of B cell memory by analyzing the (p-azophenylarsonate) Ars response in a line of A strain mice in which expression of human Bcl-2 was enforced in the B cell compartment. Previous studies of the Ars immune response in these A. Bcl-2 mice, demonstrated that a large percentage of the antibodies expressed by the Ars induced memory B cell compartment had accumulated point mutations via somatic hypermutation that increased their affinity for both Ars and the autoantigen DNA (“dual reactive” antibodies). This was in sharp contrast to normal A strain mice which displayed no dual reactive B cells in their Ars induced memory B cell compartment. These data suggested that interference with apoptotic pathways regulated by Bcl-2 allows developing memory B cells that have acquired autoreactivity to bypass a peripheral tolerance checkpoint. Further studies of these mice, reported here, demonstrate that enforced expression of Bcl-2 does not alter serum antibody affinity maturation nor positive selection of B cells expressing somatically mutated antibody with an increased affinity for Ars. Moreover, the somatic hypermutation process was unaffected in A. Bcl-2 mice. Thus, enforced expression of Bcl-2 in A. Bcl-2 mice appears to selectively alter a negative selection process that operates during memory B cell differentiation.

scholarly journals Sequential activation and distinct functions for distal and proximal modules within the IgH 3′ regulatory region

2016 ◽  
Vol 113 (6) ◽  
pp. 1618-1623 ◽  
Author(s):  
Armand Garot ◽  
Marie Marquet ◽  
Alexis Saintamand ◽  
Sébastien Bender ◽  
Sandrine Le Noir ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Heavy Chain ◽  
Somatic Hypermutation ◽  
Regulatory Region ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Receptor Expression ◽  
Class Switch ◽  
Cell Ontogeny

As a master regulator of functional Ig heavy chain (IgH) expression, the IgH 3′ regulatory region (3′RR) controls multiple transcription events at various stages of B-cell ontogeny, from newly formed B cells until the ultimate plasma cell stage. The IgH 3′RR plays a pivotal role in early B-cell receptor expression, germ-line transcription preceding class switch recombination, interactions between targeted switch (S) regions, variable region transcription before somatic hypermutation, and antibody heavy chain production, but the functional ranking of its different elements is still inaccurate, especially that of its evolutionarily conserved quasi-palindromic structure. By comparing relevant previous knockout (KO) mouse models (3′RR KO and hs3b-4 KO) to a novel mutant devoid of the 3′RR quasi-palindromic region (3′PAL KO), we pinpointed common features and differences that specify two distinct regulatory entities acting sequentially during B-cell ontogeny. Independently of exogenous antigens, the 3′RR distal part, including hs4, fine-tuned B-cell receptor expression in newly formed and naïve B-cell subsets. At mature stages, the 3′RR portion including the quasi-palindrome dictated antigen-dependent locus remodeling (global somatic hypermutation and class switch recombination to major isotypes) in activated B cells and antibody production in plasma cells.

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