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

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.

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Epstein-Barr Virus Induces Adhesion Receptor CD226 (DNAM-1) Expression during Primary B-Cell Transformation into Lymphoblastoid Cell Lines

mSphere ◽

10.1128/msphere.00305-17 ◽

2017 ◽

Vol 2 (6) ◽

Cited By ~ 5

Author(s):

Lisa Grossman ◽

Chris Chang ◽

Joanne Dai ◽

Pavel A. Nikitin ◽

Dereje D. Jima ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Cell Lines ◽

Epstein Barr Virus ◽

Human Herpesvirus ◽

Barr Virus ◽

Ebv Infection ◽

Cellular Aggregation ◽

Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) is a common human herpesvirus that establishes latency in B cells. While EBV infection is asymptomatic for most individuals, immune-suppressed individuals are at significantly higher risk of a form of EBV latent infection in which infected B cells are reactivated, grow unchecked, and generate lymphomas. This form of latency is modeled in the laboratory by infecting B cells from the blood of normal human donors in vitro. In this model, we identified a protein called CD226 that is induced by EBV but is not normally expressed on B cells. Rather, it is known to play a role in aggregation and survival signaling of non-B cells in the immune system. Cultures of EBV-infected cells adhere to one another in “clumps,” and while the proteins that are responsible for this cellular aggregation are not fully understood, we hypothesized that this form of cellular aggregation may provide a survival advantage. In this article, we characterize the mechanism by which EBV induces this protein and its expression on lymphoma tissue and cell lines and characterize EBV-infected cell lines in which CD226 has been knocked out. Epstein-Barr virus (EBV), an oncogenic herpesvirus, infects and transforms primary B cells into immortal lymphoblastoid cell lines (LCLs), providing a model for EBV-mediated tumorigenesis. EBV transformation stimulates robust homotypic aggregation, indicating that EBV induces molecules that mediate cell-cell adhesion. We report that EBV potently induced expression of the adhesion molecule CD226, which is not normally expressed on B cells. We found that early after infection of primary B cells, EBV promoted an increase in CD226 mRNA and protein expression. CD226 levels increased further from early proliferating EBV-positive B cells to LCLs. We found that CD226 expression on B cells was independent of B-cell activation as CpG DNA failed to induce CD226 to the extent of EBV infection. CD226 expression was high in EBV-infected B cells expressing the latency III growth program, but low in EBV-negative and EBV latency I-infected B-lymphoma cell lines. We validated this correlation by demonstrating that the latency III characteristic EBV NF-κB activator, latent membrane protein 1 (LMP1), was sufficient for CD226 upregulation and that CD226 was more highly expressed in lymphomas with increased NF-κB activity. Finally, we found that CD226 was not important for LCL steady-state growth, survival in response to apoptotic stress, homotypic aggregation, or adhesion to activated endothelial cells. These findings collectively suggest that EBV induces expression of a cell adhesion molecule on primary B cells that may play a role in the tumor microenvironment of EBV-associated B-cell malignancies or facilitate adhesion in the establishment of latency in vivo. IMPORTANCE Epstein-Barr virus (EBV) is a common human herpesvirus that establishes latency in B cells. While EBV infection is asymptomatic for most individuals, immune-suppressed individuals are at significantly higher risk of a form of EBV latent infection in which infected B cells are reactivated, grow unchecked, and generate lymphomas. This form of latency is modeled in the laboratory by infecting B cells from the blood of normal human donors in vitro. In this model, we identified a protein called CD226 that is induced by EBV but is not normally expressed on B cells. Rather, it is known to play a role in aggregation and survival signaling of non-B cells in the immune system. Cultures of EBV-infected cells adhere to one another in “clumps,” and while the proteins that are responsible for this cellular aggregation are not fully understood, we hypothesized that this form of cellular aggregation may provide a survival advantage. In this article, we characterize the mechanism by which EBV induces this protein and its expression on lymphoma tissue and cell lines and characterize EBV-infected cell lines in which CD226 has been knocked out.

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Covalent Linkage of HIV-1 Trimers to Synthetic Liposomes Elicits Improved B Cell and Antibody Responses

Journal of Virology ◽

10.1128/jvi.00443-17 ◽

2017 ◽

Vol 91 (16) ◽

Cited By ~ 31

Author(s):

Shridhar Bale ◽

Geraldine Goebrecht ◽

Armando Stano ◽

Richard Wilson ◽

Takayuki Ota ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Germinal Center ◽

Neutralizing Antibodies ◽

Tier 2 ◽

Covalent Linkage ◽

His Tag ◽

Hiv 1

ABSTRACT We have demonstrated that a liposomal array of well-ordered trimers enhances B cell activation, germinal center formation, and the elicitation of tier-2 autologous neutralizing antibodies. Previously, we coupled well-ordered cleavage-independent NFL trimers via their C-terminal polyhistidine tails to nickel lipids integrated into the lipid bilayer. Despite favorable in vivo effects, concern remained over the potentially longer-term in vivo instability of noncovalent linkage of the trimers to the liposomes. Accordingly, we tested both cobalt coupling and covalent linkage of the trimers to the liposomes by reengineering the polyhistidine tail to include a free cysteine on each protomer of model BG505 NFL trimers to allow covalent linkage. Both cobalt and cysteine coupling resulted in a high-density array of NFL trimers that was stable in both 20% mouse serum and 100 mM EDTA, whereas the nickel-conjugated trimers were not stable under these conditions. Binding analysis and calcium flux with anti-Env-specific B cells confirmed that the trimers maintained conformational integrity following coupling. Following immunization of mice, serologic analysis demonstrated that the covalently coupled trimers elicited Env-directed antibodies in a manner statistically significantly improved compared to soluble trimers and nickel-conjugated trimers. Importantly, the covalent coupling not only enhanced gp120-directed responses compared to soluble trimers, it also completely eliminated antibodies directed to the C-terminal His tag located at the “bottom” of the spike. In contrast, soluble and noncovalent formats efficiently elicited anti-His tag antibodies. These data indicate that covalent linkage of well-ordered trimers to liposomes in high-density array displays multiple advantages in vitro and in vivo. IMPORTANCE Enveloped viruses typically encode a surface-bound glycoprotein that mediates viral entry into host cells and is a primary target for vaccine design. Liposomes with modified lipid head groups have a unique feature of capturing and displaying antigens on their surfaces, mimicking the native pathogens. Our first-generation nickel-based liposomes captured HIV-1 Env glycoprotein trimers via a noncovalent linkage with improved efficacy over soluble glycoprotein in activating germinal center B cells and eliciting tier-2 autologous neutralizing antibodies. In this study, we report the development of second-generation cobalt- and maleimide-based liposomes that have improved in vitro stability over nickel-based liposomes. In particular, the maleimide liposomes captured HIV-1 Env trimers via a more stable covalent bond, resulting in enhanced germinal center B cell responses that generated higher antibody titers than the soluble trimers and liposome-bearing trimers via noncovalent linkages. We further demonstrate that covalent coupling prevents release of the trimers prior to recognition by B cells and masks a nonneutralizing determinant located at the bottom of the trimer.

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Molecular Evidence for Rhesus Lymphocryptovirus Infection of Epithelial Cells in Immunosuppressed Rhesus Macaques

Journal of Virology ◽

10.1128/jvi.78.7.3455-3461.2004 ◽

2004 ◽

Vol 78 (7) ◽

pp. 3455-3461 ◽

Cited By ~ 23

Author(s):

Jeffery L. Kutok ◽

Sherry Klumpp ◽

Meredith Simon ◽

John J. MacKey ◽

Vuong Nguyen ◽

...

Keyword(s):

Epithelial Cell ◽

Epithelial Cells ◽

B Cell ◽

Rhesus Macaques ◽

Molecular Evidence ◽

Cell Infection ◽

Barr Virus ◽

Ebv Infection ◽

Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) is a human oncogenic herpesvirus associated with epithelial cell and B-cell malignancies. EBV infection of B lymphocytes is essential for acute and persistent EBV infection in humans; however, the role of epithelial cell infection in the normal EBV life cycle remains controversial. The rhesus lymphocryptovirus (LCV) is an EBV-related herpesvirus that naturally infects rhesus macaques and can be used experimentally to model persistent B-cell infection and B-cell lymphomagenesis. We now show that the rhesus LCV can infect epithelial cells in immunosuppressed rhesus macaques and can induce epithelial cell lesions resembling oral hairy leukoplakia in AIDS patients. Electron microscopy, immunohistochemistry, and DNA-RNA in situ hybridization were used to identify the presence of a lytic rhesus LCV infection in these proliferative, hyperkeratotic, or parakeratotic epithelial cell lesions. These studies demonstrate that the rhesus LCV has tropism for epithelial cells, in addition to B cells, and is a relevant animal model system for studying the role of epithelial cell infection in EBV pathogenesis.

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Persistence of functional memory B cells recognizing SARS-CoV-2 variants despite loss of specific IgG

10.1101/2021.05.15.21257210 ◽

2021 ◽

Author(s):

Stephan Winklmeier ◽

Katharina Eisenhut ◽

Damla Taskin ◽

Heike Ruebsamen ◽

Celine Schneider ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Post Infection ◽

Neutralizing Antibodies ◽

Memory B Cells ◽

B Cell Differentiation ◽

Memory B Cell ◽

Specific Serum ◽

Serum Igg

While some COVID-19 patients maintain SARS-CoV-2-specific serum IgGs for more than 6 months post-infection, others, especially mild cases, eventually lose IgG levels. We aimed to assess the persistence of SARS-CoV-2-specific B cells in patients who have lost specific IgGs and analyzed the reactivity of the immunoglobulins produced by these B cells. Circulating IgG memory B cells specific for SARS-CoV-2 were detected in all 16 patients 1-8 months post-infection, and 11 participants had specific IgA B cells. Four patients lost specific serum IgG after 5-8 months but had SARS-CoV-2-specific-B-cell levels comparable to those of seropositive donors. Immunoglobulins produced after in vitro differentiation blocked receptor-binding domain (RBD) binding to the cellular receptor ACE-2, indicating neutralizing activity. Memory-B-cell-derived IgGs recognized the RBD of B.1.1.7 similarly to the wild-type, while reactivity to B.1.351 and P.1. decreased by 30% and 50%, respectively. Memory-B-cell differentiation into antibody-producing cells is a more sensitive method for detecting previous infection than measuring serum antibodies. Circulating SARS-CoV-2 IgG memory B cells persist, even in the absence of specific serum IgG; produce neutralizing antibodies; and show differential cross-reactivity to emerging variants of concern. These features of SARS-CoV-2-specific memory B cells will help to understand and promote long-term protection.

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Distinct Ex Vivo Susceptibility of B-Cell Subsets to Epstein-Barr Virus Infection According to Differentiation Status and Tissue Origin

Journal of Virology ◽

10.1128/jvi.02630-07 ◽

2008 ◽

Vol 82 (9) ◽

pp. 4400-4412 ◽

Cited By ~ 21

Author(s):

Marcus Dorner ◽

Franziska Zucol ◽

Christoph Berger ◽

Rahel Byland ◽

Gregory T. Melroe ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Ex Vivo ◽

Memory B Cells ◽

Barr Virus ◽

Ebv Infection ◽

Epstein Barr ◽

Differentiation Status ◽

B Cell Subsets

ABSTRACT Epstein-Barr virus (EBV) uses tonsils as the portal of entry to establish persistent infection. EBV is found in various B-cell subsets in tonsils but exclusively in memory B cells in peripheral blood. The in vitro susceptibilities of B-cell subsets to EBV infection have been studied solely qualitatively. In this work, we examined quantitatively the in vitro susceptibilities of various B-cell subsets from different tissue origins to EBV infection. First, we established a centrifugation-based inoculation protocol (spinoculation) that resulted in a significantly increased proportion of infected cells compared to that obtained by conventional inoculation, enabling a detailed susceptibility analysis. Importantly, B-cell infection occurred via the known EBV receptors and infected cells showed EBV mRNA expression patterns similar to those observed after conventional inoculation, validating our approach. Tonsillar naïve and memory B cells were infected ex vivo at similar frequencies. In contrast, memory B cells from blood, which represent B cells from various lymphoid tissues, were infected at lower frequencies than their naïve counterparts. Immunoglobulin A (IgA)-positive or IgG-positive tonsillar memory B cells were significantly more susceptible to EBV infection than IgM-positive counterparts. Memory B cells were transformed with lower efficiency than naïve B cells. This result was paralleled by lower proliferation rates. In summary, these data suggest that EBV exploits the B-cell differentiation status and tissue origin to establish persistent infection.

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Heat Shock Protein 90 Expression in Epstein-Barr Virus-Infected B Cells Promotes γδ T-Cell Proliferation In Vitro

Journal of Virology ◽

10.1128/jvi.79.11.7255-7261.2005 ◽

2005 ◽

Vol 79 (11) ◽

pp. 7255-7261 ◽

Cited By ~ 23

Author(s):

Maria Kotsiopriftis ◽

Jerome E. Tanner ◽

Caroline Alfieri

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

Cell Surface ◽

B Cell ◽

Γδ T Cells ◽

Γδ T Cell ◽

Barr Virus ◽

Ebv Infection

ABSTRACT The aim of this study was to elucidate the in vitro response of γδ T cells to Epstein-Barr virus (EBV)-infected B cells and to determine whether EBV-induced heat shock proteins (HSPs) might serve as γδ T-cell stimulants. Cytofluorometric analysis revealed HSP90 cell surface expression in 12% of the EBV-immortalized B-cell population in all four of the B-cell lines tested. HSP27, HSP60, and HSP70 were not detected on the cell surface by cytofluorometry in these same B-cell lines. HSP90 and HSP60, but not HSP70 or HSP27, were detected on the cell surface after 125I cell surface labeling and immunoprecipitation with anti-human HSP monoclonal antibodies. In vitro kinetic studies indicated that γδ T cells increased at least twofold by day 11 postinfection in cultures of EBV-seronegative peripheral blood lymphocytes infected with EBV, whereas percentages of αβ T cells in these same cultures either decreased slightly or remained relatively unchanged in response to EBV infection. Addition of anti-human HSP90 monoclonal antibody to the EBV-infected lymphocyte cultures inhibited γδ T-cell expansion by 92%. The inhibition of γδ T-cell expansion by anti-HSP90 antibody was reversed upon treatment with exogenous HSP90. Taken together, these results indicate that HSP90 played an important role in the stimulation of γδ T cells during EBV infection of B cells in vitro and may serve as an important immunomodulator of γδ T cells during acute EBV infection.

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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

Frontiers in Immunology ◽

10.3389/fimmu.2020.608003 ◽

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.

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Ligation of tumour-produced mucins to CD22 dramatically impairs splenic marginal zone B-cells

Biochemical Journal ◽

10.1042/bj20081241 ◽

2009 ◽

Vol 417 (3) ◽

pp. 673-683 ◽

Cited By ~ 13

Author(s):

Munetoyo Toda ◽

Risa Hisano ◽

Hajime Yurugi ◽

Kaoru Akita ◽

Kouji Maruyama ◽

...

Keyword(s):

Sialic Acid ◽

B Cells ◽

B Cell ◽

Marginal Zone ◽

Cell Signalling ◽

Negative Regulator ◽

Mammary Adenocarcinoma ◽

Marginal Zone B Cells ◽

Tumour Bearing

CD22 [Siglec-2 (sialic acid-binding, immunoglobulin-like lectin-2)], a negative regulator of B-cell signalling, binds to α2,6- sialic acid-linked glycoconjugates, including a sialyl-Tn antigen that is one of the typical tumour-associated carbohydrate antigens expressed on various mucins. Many epithelial tumours secrete mucins into tissues and/or the bloodstream. Mouse mammary adenocarcinoma cells, TA3-Ha, produce a mucin named epiglycanin, but a subline of them, TA3-St, does not. Epiglycanin binds to CD22 and inhibits B-cell signalling in vitro. The in vivo effect of mucins in the tumour-bearing state was investigated using these cell lines. It should be noted that splenic MZ (marginal zone) B-cells were dramatically reduced in the mice bearing TA3-Ha cells but not in those bearing TA3-St cells, this being consistent with the finding that the thymus-independent response was reduced in these mice. When the mucins were administered to normal mice, a portion of them was detected in the splenic MZ associated with the MZ B-cells. Furthermore, administration of mucins to normal mice clearly reduced the splenic MZ B-cells, similar to tumour-bearing mice. These results indicate that mucins in the bloodstream interacted with CD22, which led to impairment of the splenic MZ B-cells in the tumour-bearing state.

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AB0024 IN VITRO CHARACTERIZATION OF CENERIMOD, A POTENT AND SELECTIVE SPHINGOSINE 1-PHOSPHATE RECEPTOR 1 (S1P1) MODULATOR IN PREVENTING MIGRATION OF NON-ACTIVATED AND ACTIVATED PRIMARY HUMAN B CELLS IN THE PRESENCE OR ABSENCE OF GLUCOCORTICOIDS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.2482 ◽

2021 ◽

Vol 80 (Suppl 1) ◽

pp. 1046.1-1046

Author(s):

L. Schlicher ◽

P. Kulig ◽

M. Murphy ◽

M. Keller

Keyword(s):

B Cells ◽

B Cell ◽

B Lymphocytes ◽

Cell Activation ◽

Surface Expression ◽

Cell Surface Expression ◽

B Cell Activation ◽

Human B Cells ◽

Circulating Lymphocytes

Background:Cenerimod is a potent, selective, and orally active sphingosine 1-phosphate receptor 1 (S1P1) modulator that is currently being evaluated in a Phase 2b study in patients with systemic lupus erythematosus (SLE) (NCT03742037). S1P1 receptor modulators sequester circulating lymphocytes within lymph nodes, thereby reducing pathogenic autoimmune cells (including B lymphocytes) in the blood stream and in inflamed tissues. Extensive clinical experience has become available for the nonselective S1P receptor modulator fingolimod in relapsing forms of multiple sclerosis, supporting this therapeutic concept for the treatment of autoimmune disorders.Objectives:Although the effect of S1P-receptor modulators in reducing peripheral B cells is well documented1,2, the role of the S1P1 receptor on this cell type is only incompletely understood. In this study, the mode of action of cenerimod on primary human B cells was investigated in a series of in vitro experiments, including S1P1 receptor cell surface expression and chemotaxis towards S1P. Moreover, S1P1 expression following B cell activation in vitro was studied. As glucocorticoids (GC) are frequently used in the treatment of patients with autoimmune disorders including SLE, the potential influence of GC on the mode of action of cenerimod was evaluated.Methods:Primary human B lymphocytes from healthy donors were isolated from whole blood. In one set of experiments, cells were treated with different concentrations of cenerimod to measure S1P1 receptor internalization by flow cytometry. In a second set of experiments, isolated B cells were activated using different stimuli or left untreated. Cells were then analysed for S1P1 and CD69 cell surface expression and tested in a novel real-time S1P-mediated migration assay. In addition, the effect of physiological concentrations of GCs (prednisolone and prednisone) on cenerimod activity in preventing S1P mediated migration was tested.Results:In vitro, cenerimod led to a dose-dependent internalization of the S1P1 receptor on primary human B lymphocytes. Cenerimod also blocked migration of nonactivated and activated B lymphocytes towards S1P in a concentration-dependent manner, which is in line with the retention of lymphocytes in the lymph node and the reduction of circulating lymphocytes observed in the clinical setting. Upon B cell activation, which was monitored by CD69 upregulation, a simultaneous downregulation of S1P1 expression was detected, leading to less efficient S1P-directed cell migration. Importantly, physiological concentrations of GC did not affect the inhibitory activity of cenerimod on B cell migration.Conclusion:These results show that cenerimod, by modulating S1P1, blocks B lymphocyte migration towards its natural chemoattractant S1P and demonstrate compatibility of cenerimod with GC. These results are consistent with results of comparable experiments done previously using primary human T lymphocytes.References:[1]Nakamura M et al., Mult Scler. 2014 Sep; 20(10):1371-80.[2]Strasser DS et al., RMD Open 2020;6:e001261.Disclosure of Interests:None declared

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Stereotypic neutralizing VH antibodies against SARS-CoV-2 spike protein receptor binding domain in COVID-19 patients and healthy individuals

Science Translational Medicine ◽

10.1126/scitranslmed.abd6990 ◽

2021 ◽

pp. eabd6990

Author(s):

Sang Il Kim ◽

Jinsung Noh ◽

Sujeong Kim ◽

Younggeun Choi ◽

Duck Kyun Yoo ◽

...

Keyword(s):

B Cells ◽

Receptor Binding ◽

Neutralizing Antibodies ◽

De Novo ◽

Binding Domain ◽

Host Cells ◽

Spike Protein ◽

Receptor Binding Domain ◽

Healthy Individuals

Stereotypic antibody clonotypes exist in healthy individuals and may provide protective immunity against viral infections by neutralization. We observed that 13 out of 17 patients with COVID-19 had stereotypic variable heavy chain (VH) antibody clonotypes directed against the receptor-binding domain (RBD) of SARS-CoV-2 spike protein. These antibody clonotypes were comprised of immunoglobulin heavy variable (IGHV)3-53 or IGHV3-66 and immunoglobulin heavy joining (IGHJ)6 genes. These clonotypes included IgM, IgG3, IgG1, IgA1, IgG2, and IgA2 subtypes and had minimal somatic mutations, which suggested swift class switching after SARS-CoV-2 infection. The different immunoglobulin heavy variable chains were paired with diverse light chains resulting in binding to the RBD of SARS-CoV-2 spike protein. Human antibodies specific for the RBD can neutralize SARS-CoV-2 by inhibiting entry into host cells. We observed that one of these stereotypic neutralizing antibodies could inhibit viral replication in vitro using a clinical isolate of SARS-CoV-2. We also found that these VH clonotypes existed in six out of 10 healthy individuals, with IgM isotypes predominating. These findings suggest that stereotypic clonotypes can develop de novo from naïve B cells and not from memory B cells established from prior exposure to similar viruses. The expeditious and stereotypic expansion of these clonotypes may have occurred in patients infected with SARS-CoV-2 because they were already present.

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