scholarly journals Vaccine Elicitation of HIV Broadly Neutralizing Antibodies from Engineered B cells

2020 ◽  
Author(s):  
Deli Huang ◽  
Jenny Tuyet Tran ◽  
Alex Olson ◽  
Thomas Vollbrecht ◽  
Mariia V. Guryleva ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Neutralizing Antibodies ◽  
Plasma Cells ◽  
Somatic Hypermutation ◽  
Wild Type ◽  
Broadly Neutralizing Antibodies ◽  
Low Frequencies ◽  
Primary Mouse ◽  
Functional Receptor

HIV broadly neutralizing antibodies (bnAbs) can suppress viremia and protect against infection1. However, their elicitation is made difficult by low frequencies of appropriate precursor B cell receptors and the complex maturation pathways required to generate bnAbs from these precursors2. Antibody genes can be engineered into B cells for expression as both a functional receptor on cell surfaces and as secreted antibody3–5. Here, we show that HIV bnAb-engineered primary mouse B cells can be adoptively transferred and vaccinated in immunocompetent wild-type animals resulting in the expansion of durable bnAb memory and long-lived plasma cells. Somatic hypermutation after immunization indicated that engineered cells have the capacity to respond to an evolving pathogen. These results encourage further exploration of engineered B cell vaccines as a strategy for durable elicitation of HIV bnAbs to protect against infection and as a contributor to a functional cure.

scholarly journals Vaccine elicitation of HIV broadly neutralizing antibodies from engineered B cells

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Deli Huang ◽  
Jenny Tuyet Tran ◽  
Alex Olson ◽  
Thomas Vollbrecht ◽  
Mary Tenuta ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Neutralizing Antibodies ◽  
Plasma Cells ◽  
Somatic Hypermutation ◽  
Hiv Cure ◽  
Broadly Neutralizing Antibodies ◽  
Low Frequencies ◽  
Primary Mouse ◽  
Immunocompetent Mice

AbstractHIV broadly neutralizing antibodies (bnAbs) can suppress viremia and protect against HIV infection. However, their elicitation is made difficult by low frequencies of appropriate precursor B cell receptors and the complex maturation pathways required to generate bnAbs from these precursors. Antibody genes can be engineered into B cells for expression as both a functional antigen receptor on cell surfaces and as secreted antibody. Here, we show that HIV bnAb-engineered primary mouse B cells can be adoptively transferred and vaccinated in immunocompetent mice resulting in the expansion of durable bnAb memory and long-lived plasma cells. Somatic hypermutation after immunization indicates that engineered cells have the capacity to respond to an evolving pathogen. These results encourage further exploration of engineered B cell vaccines as a strategy for durable elicitation of HIV bnAbs to protect against infection and as a contributor to a functional HIV cure.

scholarly journals The Role of CXCL13 in Antibody Responses to HIV-1 Infection and Vaccination

2021 ◽  
Vol 12 ◽  
Author(s):  
Yonas Bekele Feyissa ◽  
Francesca Chiodi ◽  
Yongjun Sui ◽  
Jay A. Berzofsky
Keyword(s):  
B Cells ◽  
B Cell ◽  
Neutralizing Antibodies ◽  
Plasma Cells ◽  
B Cell Lymphoma ◽  
Cell Trafficking ◽  
Broadly Neutralizing Antibodies ◽  
G Protein Coupled ◽  
Hiv 1

CXCL13 signals through the G protein-coupled chemokine receptor CXCR5 to drive development of secondary lymphoid tissue as well as B cell and Tfh cell trafficking to germinal centers (GC), which leads to the differentiation of B cells to plasma cells and memory B cells. CXCL13 has been proposed as a general plasma biomarker for GC activities. In HIV-1 infected individuals, plasma CXCL13 levels have been associated with the rate of disease progression to AIDS. Moreover, CXCL13 production has been reported to be increased in HIV-1-infected lymph nodes, which may drive increased downregulation of CXCR5. In this review, we address the role of CXCL13 in HIV-1 infected individuals with regard to GC formation, generation of broadly neutralizing antibodies after infection and vaccination, and AIDS-related B cell lymphoma.

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.

The TNF Family Members BAFF and APRIL Play an Important Role in Hodgkin Lymphoma.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 22-22 ◽  
Author(s):  
April Chiu ◽  
Xugang Qiao ◽  
Bing He ◽  
Elizabeth Hyjjek ◽  
Joong Lee ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Hodgkin Lymphoma ◽  
Cell Lines ◽  
Plasma Cells ◽  
Somatic Hypermutation ◽  
Cytidine Deaminase ◽  
Dna Recombination ◽  
Classical Pathway ◽  
Bax Protein

Abstract Introduction. B cell-activating factor of the TNF family (BAFF) and a proliferation-inducing ligand (APRIL), a BAFF-related molecule, play a key role in the survival and proliferation of mature B cells. In addition, BAFF and APRIL cooperate with IL-4 to induce class switch DNA recombination (CSR) from IgM (or IgG) to IgG, IgA or IgE. This process requires activation-induced-cytidine deaminase (AID), a DNA-editing enzyme involved also in Ig somatic hypermutation and lymphomagenesis. BAFF and APRIL are usually produced by myeloid cells, including dendritic cells, macrophages and granulocytes, and engage three receptors preferentially expressed on B cells, including transmembrane activator and calcium modulator and cyclophylin ligand interactor (TACI), B cell maturation antigen (BCMA), and BAFF receptor (BAFF-R). Our previous studies show that BAFF and APRIL are EBV-inducible molecules implicated in B cell non-Hodgkin’s lymphoma (NHL). The scope of the present studies was to elucidate the expression and function of BAFF, APRIL, TACI, BCMA and BAFF-R in Hodgkin lymphoma (HL). Methods. Tissue sections from 5 primary EBV+ HL cases and 5 primary EBV− HL cases were analyzed for BAFF, APRIL, TACI, BCMA, and BAFF-R expression through immunohistochemistry. RS cells from 6 primary cases were microdissected and analyzed for the expression of AID and CSR byproducts by RT-PCR. The expression of BAFF, APRIL, TACI, BCMA, BAFF-R, AID, and CSR byproducts was also analyzed in 5 HL cell lines cultured in the presence or absence of recombinant BAFF, APRIL and cytokines as previously described1,2,3. Results. We found that the reactive infiltrate of primary HL tumors comprises non-malignant elements, such as macrophages, granulocytes and plasma cells, expressing BAFF and APRIL. Also a variable proportion of malignant CD30+ Reed-Sternberg (RS) cells from both EBV+ and EBV− HL cases express BAFF and APRIL. Unlike NHL B cells, which usually express BAFF-R, primary RS cells and RS cell lines lack BAFF-R, but express TACI and BCMA. In the presence of BAFF or APRIL, RS cell lines are rescued from spontaneous or induced apoptosis. This effect is associated with activation of NF-κB through a classical pathway. Increased RS cell survival is also associated with up-regulation of the pro-survival BCL-2 and BCL-XL proteins, and down-regulation of the pro-apoptotic BAX protein. Finally, in the presence of BAFF or APRIL and IL-4, RS cell lines up-regulate AID expression and increase their spontaneous CSR activity. Of note, AID expression extends to primary RS cells and is associated with ongoing CSR. Conclusions. Our studies indicate that BAFF and APRIL stimulate malignant RS cells through both autocrine and paracrine pathways. Engagement of TACI and BCMA receptors by BAFF and APRIL may enhance the expansion of RS cells by attenuating apoptosis through a mechanism involving NF-κB and BCL family proteins. By up-regulating AID, signals emanating from TACI and BCMA receptors might also introduce genomic instability. Finally, considering that TACI, BCMA and AID are B cell-specific molecules and that CSR is a process confined to B cells, our findings consolidate the notion that RS cells derive from a B cell precursor.

scholarly journals Altered Germinal-Center Metabolism in B Cells in Autoimmunity

Metabolites ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 40
Author(s):  
Ashton K. Shiraz ◽  
Eric J. Panther ◽  
Christopher M. Reilly
Keyword(s):  
B Cells ◽  
B Cell ◽  
Lupus Erythematosus ◽  
Germinal Center ◽  
Plasma Cells ◽  
Somatic Hypermutation ◽  
Cell Metabolism ◽  
Affinity Maturation ◽  
B Cell Differentiation ◽  
Contributing Factors

B lymphocytes play an important role in the pathophysiology of many autoimmune disorders by producing autoantibodies, secreting cytokines, and presenting antigens. B cells undergo extreme physiological changes as they develop and differentiate. Aberrant function in tolerogenic checkpoints and the metabolic state of B cells might be the contributing factors to the dysfunctionality of autoimmune B cells. Understanding B-cell metabolism in autoimmunity is important as it can give rise to new treatments. Recent investigations have revealed that alterations in metabolism occur in the activation of B cells. Several reports have suggested that germinal center (GC) B cells of individuals with systemic lupus erythematosus (SLE) have altered metabolic function. GCs are unique microenvironments in which the delicate and complex process of B-cell affinity maturation occurs through somatic hypermutation (SHM) and class switching recombination (CSR) and where Bcl6 tightly regulates B-cell differentiation into memory B-cells or plasma cells. GC B cells rely heavily on glucose, fatty acids, and oxidative phosphorylation (OXPHOS) for their energy requirements. However, the complicated association between GC B cells and their metabolism is still not clearly understood. Here, we review several studies of B-cell metabolism, highlighting the significant transformations that occur in GC progression, and suggest possible approaches that may be investigated to more precisely target aberrant B-cell metabolism in SLE.

scholarly journals Genome-Wide Histone Acetylation Profiling in Chronic Lymphocytic Leukemia Reveals a Distinctive Signature in Stereotyped Subset #8

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1241-1241
Author(s):  
Maria Tsagiopoulou ◽  
Vicente Chapaprieta ◽  
Nuria Russiñol ◽  
Fotis Psomopoulos ◽  
Nikos Papakonstantinou ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Research Funding ◽  
Plasma Cells ◽  
Somatic Hypermutation ◽  
Memory B Cells ◽  
Site Analysis ◽  
Total Variability ◽  
Cell Subpopulations ◽  
Chromatin Acetylation

In CLL, subsets of patients carrying stereotyped B cell receptors (BcR) share similar biological and clinical features independently of IGHV gene somatic hypermutation status. Although the chromatin landscape of CLL as a whole has been recently characterized, it remains largely unexplored in stereotyped cases. Here, we analyzed the active chromatin regulatory landscape of 3 major CLL stereotyped subsets associated with clinical aggressiveness. We performed chromatin-immunoprecipitation followed by sequencing (ChIP-Seq) with an antibody for the H3K27ac histone mark in sorted CLL cells from 19 cases, including clinically aggressive subsets #1 (clan I genes/IGKV(D)1-39, IG-unmutated CLL (U-CLL)(n=3)], #2 [IGHV3-21/IGLV3-21, IG-mutated CLL (M-CLL)(n=3)] and #8 [IGHV4-39/IGKV1(D)-39, U-CLL(n=3)] which we compared to non-stereotyped CLL cases [5 M-CLL|5 U-CLL]. In addition, a series of 15 normal B cell samples from different stages of B-cell differentiation were analyzed [naive B cells from peripheral blood (n=3), tonsillar naive B cells (n=3), germinal centre (GC) B cells (n=3), memory B cells (n=3), tonsillar plasma cells (n=3)]. Initial unsupervised principal component analysis (PCA) disclosed a distinct chromatin acetylation pattern in CLL, regardless of stereotypy status, versus normal B cells. CLL as a whole was found to be closer to naive and memory B cells rather than GC B cells and plasma cells. Detailed analysis of individual principal components (PC) revealed that PC4, which accounts for 5% of the total variability, segregated subset #8 cases and GC B cells from other CLLs and normal B cell subpopulations. Although PC4 accounts for only a small part of the total variability (5%), this suggests that subset #8 cases may share some chromatin features with proliferating GC B cells, in line with the fact that subset #8 BcR are IgG-switched. We also investigated whether stereotyped CLLs have different chromatin acetylation features compared to non-stereotyped CLLs matched by IGHV somatic hypermutation status and identified 878 Differential Regions (DR) in subset #8 vs. U-CLL, 84 DR in subset #1 vs. U-CLL and 66 DR in #2 compared vs. M-CLL. As subset #8 cases seemed to have the most distinct profile, we further characterized the detected regions. The 435 and 443 regions gaining and losing activation, respectively, mostly targeted promoters (29.5%) and regulatory elements located in introns (31%) and distal intergenic regions (21.8%). Hierarchical clustering based on the 878 DRs enabled the clear discrimination of subset #8 cases from U-CLL and normal B cells; however, it is worth noting that for several of these 878 DRs the acetylation patterns were shared between subset #8 and normal B cell subpopulations rather than subset #8 and U-CLL. Of note, 11/435 regions gaining activity on subset #8 were found within the gene encoding for the EBF1 transcription factor (TF); additional regions were associated with genes significant to CLL pathogenesis, e.g. TCF4 and E2F1. Moreover, 3 DRs losing activity in subset #8 were located within the CTLA4 gene and 2 DRs within the IL21R gene, which we have recently reported as hypermethylated and not expressed in subset #8. Next, we performed TF binding site analysis by MEME/AME suit, separately for regions gaining or losing activity, and identified significant enrichment (adj-p<0.001) on TFs such as AP-1, FOX, GATA, IRF. The regions losing activity in subset #8 showed a higher number of enriched TFs versus those gaining activity (165 vs 93 TFs), particularly displaying enrichment for many HOX family members . However, a cluster of TFs with enrichment on TF binding site analysis, such as FOXO1, FOXP1, MEF2D, PRDM1, RUNX1, RXRA, STAT6, were also located within the 878 DRs discriminating subset #8 from either U-CLL or normal B cell subpopulations. Taken together, subset #8 cases have a distinct chromatin acetylation signature which includes both loss and gain of active elements, shared features with proliferating GC B cells, and specific changes in chromatin activity of several genes and TFs relevant to B cell/CLL biology. These findings further underscore the concept that BcR stereotypy defines subsets of patients with consistent biological profile, while they may also be relevant to the particular clinical behavior of subset #8, known to be associated with the highest risk of Richter's transformation amongst all CLL. Disclosures Stamatopoulos: Abbvie: Honoraria, Research Funding; Janssen: Honoraria, Research Funding.

scholarly journals Anti-HIV-1 B cell responses are dependent on B cell precursor frequency and antigen binding affinity

2018 ◽  
Author(s):  
Pia Dosenovic ◽  
Ervin E. Kara ◽  
Anna-Klara Pettersson ◽  
Andrew McGuire ◽  
Matthew Gray ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Germinal Center ◽  
Neutralizing Antibodies ◽  
Cell Receptor ◽  
Broadly Neutralizing Antibodies ◽  
Precursor Frequency ◽  
The Relationship ◽  
Anti Hiv ◽  
Hiv 1

AbstractThe discovery that humans can produce potent broadly neutralizing antibodies (bNAbs) to several different epitopes on the HIV-1 spike has reinvigorated efforts to develop an antibody based HIV-1 vaccine. Antibody cloning from single cells revealed that nearly all bNAbs show unusual features that could help explain why it has not been possible to elicit them by traditional vaccination, and instead that it would require a sequence of different immunogens. This idea is supported by experiments with genetically modified immunoglobulin knock-in mice. Sequential immunization with a series of specifically designed immunogens was required to shepherd the development of bNAbs. However, knock-in mice contain super-physiologic numbers of bNAb precursor expressing B cells and therefore how these results can be translated to a more physiologic setting remains to be determined. Here we make use of adoptive transfer experiments using knock-in B cells that carry a synthetic intermediate in the pathway to anti-HIV-1 bNAb development to examine how the relationship between B cell receptor affinity and precursor frequency affects germinal center B cell recrutiment and clonal expansion. Immunization with soluble HIV-1 antigens can recruit bNAb precursor B cells to the germinal center when there are as few as 10 such cells per mouse. However, at low precursor frequencies the extent of clonal expansion is directly proportional to the affinity of the antigen for the B cell receptor, and recruitment to germinal centers is variable and dependent on re-circulation.Significance statementAn essential requirement for an HIV-vaccine is to elicit antibodies to conserved regions of the spike protein (Env) becasue these antibodies can protect against infection. Although broadly neutralizing antibodies develop naturally in rare individuals after prolongued HIV infection, eliciting them by vaccination has only been possible in artificial knock-in mouse models wherein the number of B cells expressing the antibody precursor is super-physiologic. To understand the relationship between precursor frequency, antigen affinity and germinal center recruitment we have performed adoptive transfer experiments in which fixed numbers of precursor cells are engrafted in wild type mice. Our results provide a framework for understanding how precursor frequency and antigen affinity shape humoral immunity to HIV.

scholarly journals B cells expressing authentic naive human VRC01-class BCRs can be primed and recruited to germinal centers in multiple independent mouse models

2020 ◽  
Author(s):  
Deli Huang ◽  
Robert K. Abbott ◽  
Colin Havenar-Daughton ◽  
Patrick D. Skog ◽  
Rita Al-Kolla ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Somatic Hypermutation ◽  
Germinal Centers ◽  
Healthy Human ◽  
Central Tenet ◽  
Class B ◽  
Precursor Frequency

ABSTRACTAnimal models of human antigen-specific B cell receptors (BCR) generally depend on “inferred germline” sequences, and thus their relationship to authentic naive human B cell BCR sequences and affinities is unclear. Here, BCR sequences from authentic naive human VRC01-class B cells from healthy human donors were selected for the generation of three new BCR knock-in mice. The BCRs span the physiological range of affinities found in humans, and use three different light chains (VK3-20, VK1-5, and VK1-33) found among subclasses of naive human VRC01-class B cells and HIV broadly neutralizing antibodies (bnAbs). The germline-targeting HIV immunogen eOD-GT8 60mer is currently in clinical trial as a candidate bnAb vaccine priming immunogen. To attempt to model human immune responses to the eOD-GT8 60mer, we tested each authentic naive human VRC01-class BCR mouse model under rare human physiological B cell precursor frequency conditions. B cells with high (HuGL18HL) or medium (HuGL17HL) affinity BCRs were primed, recruited to germinal centers, accrued substantial somatic hypermutation, and formed memory B cells. Precursor frequency and affinity interdependently influenced responses. Taken together, these experiments utilizing authentic naive human VRC01-class BCRs validate a central tenet of germline-targeting vaccine design and extend the overall concept of the reverse vaccinology approach to vaccine development.

scholarly journals Sequence intrinsic somatic mutation mechanisms contribute to affinity maturation of VRC01-class HIV-1 broadly neutralizing antibodies

2017 ◽  
Vol 114 (32) ◽  
pp. 8614-8619 ◽  
Author(s):  
Joyce K. Hwang ◽  
Chong Wang ◽  
Zhou Du ◽  
Robin M. Meyers ◽  
Thomas B. Kepler ◽  
...  
Keyword(s):  
B Cells ◽  
Neutralizing Antibodies ◽  
Somatic Hypermutation ◽  
Human Subjects ◽  
Variable Region ◽  
Affinity Maturation ◽  
Broadly Neutralizing Antibodies ◽  
Variable Regions ◽  
Complementarity Determining Regions ◽  
Hiv 1

Variable regions of Ig chains provide the antigen recognition portion of B-cell receptors and derivative antibodies. Ig heavy-chain variable region exons are assembled developmentally from V, D, J gene segments. Each variable region contains three antigen-contacting complementarity-determining regions (CDRs), with CDR1 and CDR2 encoded by the V segment and CDR3 encoded by the V(D)J junction region. Antigen-stimulated germinal center (GC) B cells undergo somatic hypermutation (SHM) of V(D)J exons followed by selection for SHMs that increase antigen-binding affinity. Some HIV-1–infected human subjects develop broadly neutralizing antibodies (bnAbs), such as the potent VRC01-class bnAbs, that neutralize diverse HIV-1 strains. Mature VRC01-class bnAbs, including VRC-PG04, accumulate very high SHM levels, a property that hinders development of vaccine strategies to elicit them. Because many VRC01-class bnAb SHMs are not required for broad neutralization, high overall SHM may be required to achieve certain functional SHMs. To elucidate such requirements, we used a V(D)J passenger allele system to assay, in mouse GC B cells, sequence-intrinsic SHM-targeting rates of nucleotides across substrates representing maturation stages of human VRC-PG04. We identify rate-limiting SHM positions for VRC-PG04 maturation, as well as SHM hotspots and intrinsically frequent deletions associated with SHM. We find that mature VRC-PG04 has low SHM capability due to hotspot saturation but also demonstrate that generation of new SHM hotspots and saturation of existing hotspot regions (e.g., CDR3) does not majorly influence intrinsic SHM in unmutated portions of VRC-PG04 progenitor sequences. We discuss implications of our findings for bnAb affinity maturation mechanisms.

scholarly journals Suppression of Signal Transducer and Activator of Transcription 3–Dependent B Lymphocyte Terminal Differentiation by Bcl-6

2000 ◽  
Vol 192 (12) ◽  
pp. 1841-1848 ◽  
Author(s):  
Rajko Reljic ◽  
Simon D. Wagner ◽  
Luke J. Peakman ◽  
Douglas T. Fearon
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Lymphocyte ◽  
Plasma Cells ◽  
Somatic Hypermutation ◽  
Terminal Differentiation ◽  
Cell Development ◽  
Signal Transducer ◽  
Effector Cells ◽  
Transcription 3

Lymphocytes usually differentiate into effector cells within days after antigen exposure, except in germinal centers where terminal differentiation is delayed while somatic hypermutation creates high-affinity antibody mutants. Here we investigate whether arrest of terminal differentiation can be mediated by BCL-6, a transcriptional repressor that is expressed by germinal center B cells and is required for this phase of B cell development. We find that BCL-6 suppresses the differentiation of transformed and primary B cells to plasma cells by inhibiting the signal transducer and activator of transcription 3–dependent expression of the major regulator of plasma cell development, the B lymphocyte–induced maturation protein (Blimp-1). This function of BCL-6 as a repressor of B lymphocyte differentiation may also underlie the association between chromosomal translocations of its gene and B cell lymphomas.

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