scholarly journals TFH Cells Induced by Vaccination and Following SIV Challenge Support Env-Specific Humoral Immunity in the Rectal-Genital Tract and Circulation of Female Rhesus Macaques

2021 ◽  
Vol 11 ◽  
Author(s):  
Sabrina Helmold Hait ◽  
Christopher James Hogge ◽  
Mohammad Arif Rahman ◽  
Ruth Hunegnaw ◽  
Zuena Mushtaq ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Humoral Immunity ◽  
Neutralizing Antibodies ◽  
Rhesus Macaques ◽  
Affinity Maturation ◽  
Cell Maturation ◽  
Female Rhesus ◽  
Specific Igg ◽  
Female Rhesus Macaques

T follicular helper (TFH) cells are pivotal in lymph node (LN) germinal center (GC) B cell affinity maturation. Circulating CXCR5+ CD4+ T (cTFH) cells have supported memory B cell activation and broadly neutralizing antibodies in HIV controllers. We investigated the contribution of LN SIV-specific TFH and cTFH cells to Env-specific humoral immunity in female rhesus macaques following a mucosal Ad5hr-SIV recombinant priming and SIV gp120 intramuscular boosting vaccine regimen and following SIV vaginal challenge. TFH and B cells were characterized by flow cytometry. B cell help was evaluated in TFH-B cell co-cultures and by real-time PCR. Vaccination induced Env-specific TFH and Env-specific memory (ESM) B cells in LNs. LN Env-specific TFH cells post-priming and GC ESM B cells post-boosting correlated with rectal Env-specific IgA titers, and GC B cells at the same timepoints correlated with vaginal Env-specific IgG titers. Vaccination expanded cTFH cell responses, including CD25+ Env-specific cTFH cells that correlated negatively with vaginal Env-specific IgG titers but positively with rectal Env-specific IgA titers. Although cTFH cells post-2nd boost positively correlated with viral-loads following SIV challenge, cTFH cells of SIV-infected and protected macaques supported maturation of circulating B cells into plasma cells and IgA release in co-culture. Additionally, cTFH cells of naïve macaques promoted upregulation of genes associated with B cell proliferation, BCR engagement, plasma cell maturation, and antibody production, highlighting the role of cTFH cells in blood B cell maturation. Vaccine-induced LN TFH and GC B cells supported anti-viral mucosal immunity while cTFH cells provided B cell help in the periphery during immunization and after SIV challenge. Induction of TFH responses in blood and secondary lymphoid organs is likely desirable for protective efficacy of HIV vaccines.

scholarly journals Shared HIV envelope-specific B cell clonotypes induced by a pox-protein vaccine regimen

2021 ◽  
Author(s):  
Kristen W. Cohen ◽  
Lamar Ballweber-Fleming ◽  
Michael Duff ◽  
Rachael E. Whaley ◽  
Aaron Seese ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Neutralizing Antibodies ◽  
Rational Design ◽  
Critical Role ◽  
Memory B Cells ◽  
Protein Vaccine ◽  
Cell Repertoire ◽  
B Cell Repertoire ◽  
Specific Igg

An effective HIV-1 vaccine will likely induce potent, broad neutralizing antibodies. No candidate vaccines have elicited these responses presumably because they fail to activate human B cell precursors that can affinity mature to generate broad neutralizing antibodies. To identify the B cell clonotypes that are elicited, we conducted in-depth analyses of the envelope-specific B cell repertoire in recipients of ALVAC-HIV vector (vCP2438) and bivalent subtype C gp120 protein (HVTN100). We observed high frequencies of envelope-specific IgG+ memory B cells with restricted immunogenetic diversity, relative to non-vaccine induced memory B cells, with preferential expansions of distinct variable genes but limited accumulation of mutations. Many envelope-specific clonotypes were shared across vaccinees, but did not overlap with the envelope-negative memory repertoire, within and across subjects. Single-cell sequencing of envelope-specific IgG+ memory B cells often revealed VH1-2*02 and VK3-20 sequence co-expression and in one case, contained a 5 amino acid CDRL3, the canonical signature of VRC01-class antibodies, confirming that these B cells are extremely rare but detectable. Our study provides evidence that immunogens play a critical role in selecting and restricting the responding B cell repertoire and supports the rational design of HIV vaccines targeting specific B cell lineages for induction of broadly-reactive neutralizing antibodies.

scholarly journals Nucleoside-modified mRNA vaccines induce potent T follicular helper and germinal center B cell responses

2018 ◽  
Vol 215 (6) ◽  
pp. 1571-1588 ◽  
Author(s):  
Norbert Pardi ◽  
Michael J. Hogan ◽  
Martin S. Naradikian ◽  
Kaela Parkhouse ◽  
Derek W. Cain ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Germinal Center ◽  
Neutralizing Antibodies ◽  
Affinity Maturation ◽  
Modified Nucleosides ◽  
Vaccine Platform ◽  
Intradermal Vaccination ◽  
Cell Responses ◽  
Follicular Helper

T follicular helper (Tfh) cells are required to develop germinal center (GC) responses and drive immunoglobulin class switch, affinity maturation, and long-term B cell memory. In this study, we characterize a recently developed vaccine platform, nucleoside-modified, purified mRNA encapsulated in lipid nanoparticles (mRNA-LNPs), that induces high levels of Tfh and GC B cells. Intradermal vaccination with nucleoside-modified mRNA-LNPs encoding various viral surface antigens elicited polyfunctional, antigen-specific, CD4+ T cell responses and potent neutralizing antibody responses in mice and nonhuman primates. Importantly, the strong antigen-specific Tfh cell response and high numbers of GC B cells and plasma cells were associated with long-lived and high-affinity neutralizing antibodies and durable protection. Comparative studies demonstrated that nucleoside-modified mRNA-LNP vaccines outperformed adjuvanted protein and inactivated virus vaccines and pathogen infection. The incorporation of noninflammatory, modified nucleosides in the mRNA is required for the production of large amounts of antigen and for robust immune responses.

Three-Dimensional Reorganization of the Genome During B Cell Affinity Maturation

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 279-279
Author(s):  
Karen L. Bunting ◽  
David Soong ◽  
Yanwen Jiang ◽  
Brandon L. Swed ◽  
Katerina Hatzi ◽  
...  
Keyword(s):  
Gene Expression ◽  
B Cells ◽  
B Cell ◽  
Three Dimensional ◽  
Affinity Maturation ◽  
Cell Maturation ◽  
Transcriptional Reprogramming ◽  
B Cell Maturation ◽  
Genome Wide ◽  
Cell Affinity

Abstract Abstract 279 B cell affinity maturation is fundamental to the development of humoral immunity. To create a diverse antibody repertoire, B cells activated in the germinal centre (GC) must undergo a profound change in phenotype. This unique phenotypic change, which features simultaneous proliferation and somatic hypermutation and which can predispose to the development of lymphoma, requires radically altered gene expression programming in GC B cells. However, the way that this gene expression program is coordinated is unknown. Emerging evidence suggests that the higher-order organization of chromatin plays a role in the co-regulation of genes. We hypothesised that the three-dimensional organization of genes and chromosomes in the nucleus of B cells plays a key role in the epigenetic and transcriptional reprogramming that underlies acquisition of the GC B cell phenotype during B cell maturation. Using genome-wide mapping of chromatin interactions (Hi-C), combined with genome-wide profiles of gene expression (RNA-seq), histone modifications and transcription factor binding (ChIP-seq) in human naïve B (NB) and GC B cells, we have discovered that the three-dimensional structure of the genome undergoes widespread reorganization during B cell maturation to coordinate the GC transcriptional programme. Conformational maps of chromosome folding in these cells reveal a novel and profound loss of inter-arm interactions, reflecting lower chromosome compaction in GC B cells. Remarkably, we observed extensive differential partitioning of genes into NB- and GC B cell-specific compartments, and demonstrate for the first time that coordinated changes in histone modifications (H3K4Me2: P=3×10−35; H3K27Ac: P=3×10−33; Fisher's exact test) and transcription (P=1×10−9) required for cell type specification is mediated by the de novo formation of precisely delimited chromosome neighbourhoods. Most strikingly, we find that remodelling of the GC B cell genome involves the specific structural unlocking of genes that drive the GC transcriptional programme, such as AICDA, MTA3, and BCL6. Coordinate activation of these genes is mediated by the expansion of gene interaction neighbourhoods, increased promoter interactivity (P=3×10−35), engagement of long-range enhancer-promoter interactions (>2-fold increase), and the formation of gene body loops (P=3.18×10−15). Intriguingly, the master regulator of GC B cell differentiation, BCL6, shows a high propensity for all of these different types of interactions, suggesting that regulation of this gene in the context of chromatin is highly complex. Integration with genome-wide binding data for the structural organizing proteins, CTCF and cohesin, as well as the cell-specific factor, PU.1, supports a specific role for these proteins in the repositioning of activated promoters and enhancer regions during B cell maturation. This study shows for the first time that the architecture of the genome is critical for specification of cellular phenotype, and that epigenetic and transcriptional reprogramming in GC B cells is functionally linked to the structural reorganization of genes in the nucleus. Importantly, the higher-order organization of chromatin could represent a novel mechanism by which GC B cell gene expression is dysregulated in lymphoma. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Alterations in B Cell and Follicular T-Helper Cell Subsets in Patients with Acute COVID-19 and COVID-19 Convalescents

2021 ◽  
Vol 44 (1) ◽  
pp. 194-205
Author(s):  
Igor V. Kudryavtsev ◽  
Natalia A. Arsentieva ◽  
Oleg K. Batsunov ◽  
Zoia R. Korobova ◽  
Irina V. Khamitova ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Humoral Immunity ◽  
N Protein ◽  
Follicular Helper ◽  
Healthy Donors ◽  
Specific Igg ◽  
Sparse Methods

Background. Humoral immunity requires interaction between B cell and T follicular helper cells (Tfh) to produce effective immune response, but the data regarding a role of B cells and Tfh in SARS-CoV-2 defense are still sparse. Methods. Blood samples from patients with acute COVID-19 (n = 64), convalescents patients who had specific IgG to SARS-CoV-2 N-protein (n = 55), and healthy donors with no detectable antibodies to any SARS-CoV-2 proteins (HC, n = 44) were analyses by multicolor flow cytometry. Results. Patients with acute COVID-19 showed decreased levels of memory B cells subsets and increased proportion plasma cell precursors compared to HC and COVID-19 convalescent patients, whereas for the latter the elevated numbers of virgin naïve, Bm2′ and “Bm3+Bm4” was found if compared with HC. During acute COVID-19 CXCR3+CCR6− Tfh1-like cells were decreased and the levels of CXCR3–CCR6+ Tfh17-like were increased then in HC and convalescent patients. Finally, COVID-19 convalescent patients had increased levels of Tfh2-, Tfh17- and DP Tfh-like cells while comparing their amount with HC. Conclusions. Our data indicate that COVID-19 can impact the humoral immunity in the long-term.

scholarly journals Epstein-Barr Virus gp350 Can Functionally Replace the Rhesus Lymphocryptovirus Major Membrane Glycoprotein and Does Not Restrict Infection of Rhesus Macaques

2015 ◽  
Vol 90 (3) ◽  
pp. 1222-1230 ◽  
Author(s):  
Marissa Herrman ◽  
Janine Mühe ◽  
Carol Quink ◽  
Fred Wang
Keyword(s):  
B Cells ◽  
B Cell ◽  
Persistent Infection ◽  
Neutralizing Antibodies ◽  
Rhesus Macaques ◽  
Membrane Glycoprotein ◽  
Cell Infection ◽  
Range Restriction ◽  
Ebv Infection

ABSTRACTPrimary Epstein-Barr virus (EBV) infection is the most common cause of infectious mononucleosis, and persistent infection is associated with multiple cancers. EBV vaccine development has focused on the major membrane glycoprotein, gp350, since it is the major target for antibodies that neutralize infection of B cells. However, EBV has tropism for both B cells and epithelial cells, and it is unknown whether serum neutralizing antibodies against B cell infection will provide sufficient protection against virus infection initiated at the oral mucosa. This could be stringently tested by passive antibody transfer and oral virus challenge in the rhesus macaque model for EBV infection. However, only neutralizing monoclonal antibodies (MAbs) against EBV are available, and EBV is unable to infect rhesus macaques because of a host range restriction with an unknown mechanism. We cloned the prototypic EBV-neutralizing antibody, 72A1, and found that recombinant 72A1 did not neutralize rhesus lymphocryptovirus (rhLCV) infection of macaque B cells. Therefore, we constructed a chimeric rhLCV in which the native major membrane glycoprotein was replaced with EBV gp350. This chimeric rhLCV became sensitive to neutralization by the 72A1 MAb, efficiently immortalized macaque B cellsin vitro, and successfully established acute and persistent infection after oral inoculation of rhesus macaques. Thus, EBV gp350 can functionally replace rhLCV gp350 and does not restrict rhLCV infectionin vitroorin vivo. The chimeric rhLCV enables direct use of an EBV-specific MAb to investigate the effects of serum neutralizing antibodies against B cell infection on oral viral challenge in rhesus macaques.IMPORTANCEThis study asked whether the EBV major membrane glycoprotein could functionally replace the rhLCV major membrane glycoprotein. We found that an rhLCV humanized with EBV gp350 is capable of efficiently immortalizing monkey B cellsin vitroand reproduces acute and persistent infection after oral inoculation of macaques. These results advance our understanding of why EBV cannot infect rhesus macaques by proving that viral attachment through gp350 is not the mechanism for EBV host range restriction. Humanization of rhLCV with EBV gp350 also confers susceptibility to a potent EBV-neutralizing MAb and provides a novel and significant enhancement to the rhesus macaque animal model where both the clinical utility and biological role of neutralizing MAbs against B cell or epithelial cell infection can now be directly tested in the most accurate animal model for EBV infection.

scholarly journals A Simple Flow-Cytometric Method Measuring B Cell Surface Immunoglobulin Avidity Enables Characterization of Affinity Maturation to Influenza A Virus

mBio ◽  
2015 ◽  
Vol 6 (4) ◽  
Author(s):  
Gregory M. Frank ◽  
Davide Angeletti ◽  
William L. Ince ◽  
James S. Gibbs ◽  
Surender Khurana ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Influenza A Virus ◽  
Germinal Center ◽  
Neutralizing Antibodies ◽  
Influenza A ◽  
Affinity Maturation ◽  
Flow Cytometric Method ◽  
Flow Cytometric ◽  
Simple Flow

ABSTRACT Antibody (Ab) affinity maturation enables an individual to maintain immunity to an increasing number of pathogens within the limits of a total Ig production threshold. A better understanding of this process is critical for designing vaccines that generate optimal Ab responses to pathogens. Our study describes a simple flow-cytometric method that enumerates virus-specific germinal center (GC) B cells as well as their AC50, a measure of Ab avidity, defined as the antigen concentration required to detect 50% of specific B cells. Using a model of mouse Ab responses to the influenza A virus hemagglutinin (IAV HA), we obtained data indicating that AC50 decreases with time postinfection in an affinity maturation-dependent process. As proof of principle of the utility of the method, our data clearly show that relative to intranasal IAV infection, intramuscular immunization against inactivated IAV in adjuvant results in a diminished GC HA B cell response, with increased AC50 correlating with an increased serum Ab off-rate. Enabling simultaneous interrogation of both GC HA B cell quantity and quality, this technique should facilitate study of affinity maturation and rational vaccine design. IMPORTANCE Though it was first described 50 years ago, little is known about how antibody affinity maturation contributes to immunity. This question is particularly relevant to developing more effective vaccines for influenza A virus (IAV) and other viruses that are difficult vaccine targets. Limitations in methods for characterizing antigen-specific B cells have impeded progress in characterizing the quality of immune responses to vaccine and natural immunogens. In this work, we describe a simple flow cytometry-based approach that measures both the number and affinity of IAV-binding germinal center B cells specific for the IAV HA, the major target of IAV-neutralizing antibodies. Using this method, we showed that the route and form of immunization significantly impacts the quality and quantity of B cell antibody responses. This method provides a relatively simple yet powerful tool for better understanding the contribution of affinity maturation to viral immunity.

scholarly journals Durable SARS-CoV-2 B cell immunity after mild or severe disease

2020 ◽  
Author(s):  
Clinton O. Ogega ◽  
Nicole E. Skinner ◽  
Paul W. Blair ◽  
Han-Sol Park ◽  
Kirsten Littlefield ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Humoral Immunity ◽  
Neutralizing Antibodies ◽  
Severe Disease ◽  
Flow Cytometric Analysis ◽  
Neutralizing Antibody ◽  
Cell Mediated Immunity ◽  
Specific Class ◽  
Cell Immunity

AbstractMultiple studies have shown loss of SARS-CoV-2 specific antibodies over time after infection, raising concern that humoral immunity against the virus is not durable. If immunity wanes quickly, millions of people may be at risk for reinfection after recovery from COVID-19. However, memory B cells (MBC) could provide durable humoral immunity even if serum neutralizing antibody titers decline. We performed multi-dimensional flow cytometric analysis of S protein receptor binding domain (S-RBD)-specific MBC in cohorts of ambulatory COVID-19 patients with mild disease, and hospitalized patients with moderate to severe disease, at a median of 54 (39-104) days after onset of symptoms. We detected S-RBD-specific class-switched MBC in 13 out of 14 participants, including 4 of the 5 participants with lowest plasma levels of anti-S-RBD IgG and neutralizing antibodies. Resting MBC (rMBC) made up the largest proportion of S-RBD-specific class-switched MBC in both cohorts. FCRL5, a marker of functional memory when expressed on rMBC, was dramatically upregulated on S-RBD-specific rMBC. These data indicate that most SARS-CoV-2-infected individuals develop S-RBD-specific, class-switched MBC that phenotypically resemble germinal center-derived B cells induced by effective vaccination against other pathogens, providing evidence for durable B cell-mediated immunity against SARS-CoV-2 after recovery from mild or severe COVID-19 disease.Graphical Abstract

scholarly journals Mechanisms underlying vaccination protocols that may optimally elicit broadly neutralizing antibodies against highly mutable pathogens

2020 ◽  
Author(s):  
Raman S. Ganti ◽  
Arup K. Chakraborty
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Population ◽  
Neutralizing Antibodies ◽  
Population Distribution ◽  
Fitness Landscape ◽  
Affinity Maturation ◽  
Host Cells ◽  
Time Varying ◽  
Broadly Neutralizing Antibodies

Effective prophylactic vaccines usually induce the immune system to generate potent antibodies that can bind to an antigen and thus prevent it from infecting host cells. B cells produce antibodies by a Darwinian evolutionary process called affinity maturation (AM). During AM, the B cell population evolves in response to the antigen. Antibodies that bind specifically and strongly to the antigen are thus produced. Highly mutable pathogens pose a major challenge to the development of effective vaccines because antibodies that are effective against one strain of the virus may not protect against a mutant strain. Antibodies that can protect against diverse strains of a mutable pathogen are called broadly neutralizing antibodies (bnAbs). In spite of extensive experimental and computational studies that have led to important advances, an effective vaccination strategy that can generate bnAbs does not exist for any highly mutable pathogen. Here we study a minimal model of AM in different time-varying antigenic environments to explore the mechanisms underlying optimal vaccination protocols that maximize the production of bnAbs. We find that the characteristics of the time-varying Kullback-Leibler distance (KLD) between the B cell population distribution and the fitness landscape imposed by antigens is a key determinant of bnAb evolution. The optimal vaccination protocol requires a relatively low KLD in the beginning in order to increase the entropy (diversity) of the B cell population so that the surviving B cells have a high chance of evolving into bnAbs upon subsequently increasing the KLD. For a discretized two-step variation in antigenic environment, there are optimal values of the KLDs for the first and second steps. Phylogenetic tree analysis further reveals the evolutionary pathways that lead to bnAbs. The connections between our results and recent simulation studies of bnAb evolution and the general problem of evolution of generalists versus specialists are discussed.

scholarly journals Chronic viral infection promotes early germinal center exit of B cells and impaired antibody development

2019 ◽  
Author(s):  
Ryan P. Staupe ◽  
Laura A. Vella ◽  
Sasikanth Manne ◽  
Josephine R. Giles ◽  
Wenzhao Meng ◽  
...  
Keyword(s):  
B Cells ◽  
Viral Infection ◽  
B Cell ◽  
Cell Fate ◽  
Humoral Immunity ◽  
Germinal Center ◽  
Affinity Maturation ◽  
Chronic Viral Infection ◽  
Cell Fate Decisions ◽  
The Impact

SUMMARYChronic viral infections disrupt B cell responses leading to impaired affinity maturation and delayed control of viremia. Previous studies have identified early pre-germinal center (GC) B cell attrition but the impact of chronic infections on B cell fate decisions in the GC remains poorly understood. To address this question, we used single-cell transcriptional profiling of virus-specific GC B cells to test the hypothesis that chronic viral infection disrupted GC B cell fate decisions leading to suboptimal humoral immunity. These studies revealed a critical GC differentiation checkpoint that is disrupted by chronic infection, specifically at the point of dark zone re-entry. During chronic viral infection, virus-specific GC B cells were shunted towards terminal plasma cell (PC) or memory B cell (MBC) fates at the expense of continued participation in the GC. Early GC exit was associated with decreased B cell mutational burden and antibody quality. Persisting antigen and inflammation independently drove facets of dysregulation, with a key role for inflammation in directing premature terminal GC B cell differentiation and GC exit. Thus, these studies define GC defects during chronic viral infection and identify a critical GC checkpoint that is short-circuited, preventing optimal maturation of humoral immunity.

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