RESUMO
Monoclonal antibodies (mAbs) are a focus in vaccine and therapeutic design to counteract severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants. Here, we combined B cell sorting with single-cell VDJ and RNA sequencing (RNA-seq) and mAb structures to characterize B cell responses against SARS-CoV-2. We show that the SARS-CoV-2-specific B cell repertoire consists of transcriptionally distinct B cell populations with cells producing potently neutralizing antibodies (nAbs) localized in two clusters that resemble memory and activated B cells. Cryo-electron microscopy structures of selected nAbs from these two clusters complexed with SARS-CoV-2 spike trimers show recognition of various receptor-binding domain (RBD) epitopes. One of these mAbs, BG10-19, locks the spike trimer in a closed conformation to potently neutralize SARS-CoV-2, the recently arising mutants B.1.1.7 and B.1.351, and SARS-CoV and cross-reacts with heterologous RBDs. Together, our results characterize transcriptional differences among SARS-CoV-2-specific B cells and uncover cross-neutralizing Ab targets that will inform immunogen and therapeutic design against coronaviruses.
Assuntos
Anticorpos Neutralizantes/imunologia , Linfócitos B/metabolismo , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/química , Anticorpos Antivirais/sangue , Anticorpos Antivirais/química , Anticorpos Antivirais/imunologia , Complexo Antígeno-Anticorpo/química , Complexo Antígeno-Anticorpo/metabolismo , Reações Antígeno-Anticorpo , Linfócitos B/citologia , Linfócitos B/virologia , COVID-19/patologia , COVID-19/virologia , Microscopia Crioeletrônica , Cristalografia por Raios X , Perfilação da Expressão Gênica , Humanos , Imunoglobulina A/imunologia , Região Variável de Imunoglobulina/química , Região Variável de Imunoglobulina/genética , Domínios Proteicos/imunologia , Multimerização Proteica , Estrutura Quaternária de Proteína , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/metabolismo , Análise de Sequência de RNA , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismoRESUMO
A proportion of patients surviving acute coronavirus disease 2019 (COVID-19) infection develop post-acute COVID syndrome (long COVID (LC)) lasting longer than 12 weeks. Here, we studied individuals with LC compared to age- and gender-matched recovered individuals without LC, unexposed donors and individuals infected with other coronaviruses. Patients with LC had highly activated innate immune cells, lacked naive T and B cells and showed elevated expression of type I IFN (IFN-ß) and type III IFN (IFN-λ1) that remained persistently high at 8 months after infection. Using a log-linear classification model, we defined an optimal set of analytes that had the strongest association with LC among the 28 analytes measured. Combinations of the inflammatory mediators IFN-ß, PTX3, IFN-γ, IFN-λ2/3 and IL-6 associated with LC with 78.5-81.6% accuracy. This work defines immunological parameters associated with LC and suggests future opportunities for prevention and treatment.
Assuntos
Linfócitos B/imunologia , COVID-19/complicações , Imunidade Inata , SARS-CoV-2/imunologia , Linfócitos T/imunologia , Adulto , Idoso , Linfócitos B/metabolismo , Linfócitos B/virologia , Biomarcadores/sangue , COVID-19/sangue , COVID-19/imunologia , COVID-19/virologia , Estudos de Casos e Controles , Citocinas/sangue , Feminino , Interações Hospedeiro-Patógeno , Humanos , Mediadores da Inflamação/sangue , Masculino , Pessoa de Meia-Idade , Prognóstico , SARS-CoV-2/patogenicidade , Índice de Gravidade de Doença , Linfócitos T/metabolismo , Linfócitos T/virologia , Fatores de Tempo , Síndrome de COVID-19 Pós-AgudaRESUMO
The integrin α4ß7 selectively regulates lymphocyte trafficking and adhesion in the gut and gut-associated lymphoid tissue (GALT). Here, we describe unexpected involvement of the tyrosine phosphatase Shp1 and the B cell lectin CD22 (Siglec-2) in the regulation of α4ß7 surface expression and gut immunity. Shp1 selectively inhibited ß7 endocytosis, enhancing surface α4ß7 display and lymphocyte homing to GALT. In B cells, CD22 associated in a sialic acid-dependent manner with integrin ß7 on the cell surface to target intracellular Shp1 to ß7. Shp1 restrained plasma membrane ß7 phosphorylation and inhibited ß7 endocytosis without affecting ß1 integrin. B cells with reduced Shp1 activity, lacking CD22 or expressing CD22 with mutated Shp1-binding or carbohydrate-binding domains displayed parallel reductions in surface α4ß7 and in homing to GALT. Consistent with the specialized role of α4ß7 in intestinal immunity, CD22 deficiency selectively inhibited intestinal antibody and pathogen responses.
Assuntos
Linfócitos B/enzimologia , Imunidade nas Mucosas , Cadeias beta de Integrinas/metabolismo , Integrinas/metabolismo , Mucosa Intestinal/enzimologia , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismo , Animais , Linfócitos B/imunologia , Linfócitos B/virologia , Quimiotaxia de Leucócito , Modelos Animais de Doenças , Endocitose , Feminino , Cadeias beta de Integrinas/imunologia , Integrinas/imunologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/virologia , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosforilação , Proteína Tirosina Fosfatase não Receptora Tipo 6/deficiência , Proteína Tirosina Fosfatase não Receptora Tipo 6/genética , Rotavirus/imunologia , Rotavirus/patogenicidade , Infecções por Rotavirus/genética , Infecções por Rotavirus/imunologia , Infecções por Rotavirus/metabolismo , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/deficiência , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/genética , Transdução de Sinais , Técnicas de Cultura de TecidosRESUMO
The present vaccine against influenza virus has the inevitable risk of antigenic discordance between the vaccine and the circulating strains, which diminishes vaccine efficacy. This necessitates new approaches that provide broader protection against influenza. Here we designed a vaccine using the hypervariable receptor-binding domain (RBD) of viral hemagglutinin displayed on a nanoparticle (np) able to elicit antibody responses that neutralize H1N1 influenza viruses spanning over 90 years. Co-display of RBDs from multiple strains across time, so that the adjacent RBDs are heterotypic, provides an avidity advantage to cross-reactive B cells. Immunization with the mosaic RBD-np elicited broader antibody responses than those induced by an admixture of nanoparticles encompassing the same set of RBDs as separate homotypic arrays. Furthermore, we identified a broadly neutralizing monoclonal antibody in a mouse immunized with mosaic RBD-np. The mosaic antigen array signifies a unique approach that subverts monotypic immunodominance and allows otherwise subdominant cross-reactive B cell responses to emerge.
Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Nanopartículas/química , Infecções por Orthomyxoviridae/imunologia , Animais , Anticorpos Neutralizantes/administração & dosagem , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Linfócitos B/virologia , Reações Cruzadas/efeitos dos fármacos , Reações Cruzadas/imunologia , Feminino , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Humanos , Imunização , Vírus da Influenza A Subtipo H1N1/metabolismo , Vírus da Influenza A Subtipo H1N1/fisiologia , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/química , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Camundongos Endogâmicos BALB C , Infecções por Orthomyxoviridae/prevenção & controle , Infecções por Orthomyxoviridae/virologiaRESUMO
Epstein-Barr virus (EBV) infection can engender severe B cell lymphoproliferative diseases1,2. The primary infection is often asymptomatic or causes infectious mononucleosis (IM), a self-limiting lymphoproliferative disorder3. Selective vulnerability to EBV has been reported in association with inherited mutations impairing T cell immunity to EBV4. Here we report biallelic loss-of-function variants in IL27RA that underlie an acute and severe primary EBV infection with a nevertheless favourable outcome requiring a minimal treatment. One mutant allele (rs201107107) was enriched in the Finnish population (minor allele frequency = 0.0068) and carried a high risk of severe infectious mononucleosis when homozygous. IL27RA encodes the IL-27 receptor alpha subunit5,6. In the absence of IL-27RA, phosphorylation of STAT1 and STAT3 by IL-27 is abolished in T cells. In in vitro studies, IL-27 exerts a synergistic effect on T-cell-receptor-dependent T cell proliferation7 that is deficient in cells from the patients, leading to impaired expansion of potent anti-EBV effector cytotoxic CD8+ T cells. IL-27 is produced by EBV-infected B lymphocytes and an IL-27RA-IL-27 autocrine loop is required for the maintenance of EBV-transformed B cells. This potentially explains the eventual favourable outcome of the EBV-induced viral disease in patients with IL-27RA deficiency. Furthermore, we identified neutralizing anti-IL-27 autoantibodies in most individuals who developed sporadic infectious mononucleosis and chronic EBV infection. These results demonstrate the critical role of IL-27RA-IL-27 in immunity to EBV, but also the hijacking of this defence by EBV to promote the expansion of infected transformed B cells.
Assuntos
Infecções por Vírus Epstein-Barr , Interleucina-27 , Receptores de Interleucina , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Adulto Jovem , Alelos , Linfócitos B/patologia , Linfócitos B/virologia , Linfócitos T CD8-Positivos/patologia , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/genética , Infecções por Vírus Epstein-Barr/terapia , Finlândia , Frequência do Gene , Herpesvirus Humano 4 , Homozigoto , Mononucleose Infecciosa/complicações , Mononucleose Infecciosa/genética , Mononucleose Infecciosa/terapia , Interleucina-27/imunologia , Interleucina-27/metabolismo , Mutação com Perda de Função , Receptores de Interleucina/deficiência , Receptores de Interleucina/genética , Receptores de Interleucina/metabolismo , Resultado do TratamentoRESUMO
SARS-CoV-2 infection has emerged as a serious global pandemic. Because of the high transmissibility of the virus and the high rate of morbidity and mortality associated with COVID-19, developing effective and safe vaccines is a top research priority. Here, we provide a detailed evaluation of the immunogenicity of lipid nanoparticle-encapsulated, nucleoside-modified mRNA (mRNA-LNP) vaccines encoding the full-length SARS-CoV-2 spike protein or the spike receptor binding domain in mice. We demonstrate that a single dose of these vaccines induces strong type 1 CD4+ and CD8+ T cell responses, as well as long-lived plasma and memory B cell responses. Additionally, we detect robust and sustained neutralizing antibody responses and the antibodies elicited by nucleoside-modified mRNA vaccines do not show antibody-dependent enhancement of infection in vitro. Our findings suggest that the nucleoside-modified mRNA-LNP vaccine platform can induce robust immune responses and is a promising candidate to combat COVID-19.
Assuntos
Anticorpos Neutralizantes/biossíntese , Anticorpos Antivirais/biossíntese , Betacoronavirus/efeitos dos fármacos , Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , RNA Mensageiro/imunologia , RNA Viral/imunologia , Vacinas Virais/administração & dosagem , Animais , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Linfócitos B/virologia , Betacoronavirus/imunologia , Betacoronavirus/patogenicidade , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/virologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/virologia , COVID-19 , Vacinas contra COVID-19 , Infecções por Coronavirus/genética , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/patologia , Modelos Animais de Doenças , Furina/genética , Furina/imunologia , Humanos , Imunidade Humoral/efeitos dos fármacos , Imunização/métodos , Imunogenicidade da Vacina , Memória Imunológica/efeitos dos fármacos , Ativação Linfocitária/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Nanopartículas/administração & dosagem , Nanopartículas/química , Pneumonia Viral/imunologia , Pneumonia Viral/patologia , RNA Mensageiro/genética , RNA Viral/genética , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Vacinas Sintéticas , Vacinas Virais/biossíntese , Vacinas Virais/genéticaRESUMO
Epstein-Barr virus (EBV) causes infectious mononucleosis and is associated with epithelial-cell cancers and B cell lymphomas. An effective EBV vaccine is not available. We found that antibodies to the EBV glycoprotein gH/gL complex were the principal components in human plasma that neutralized infection of epithelial cells and that antibodies to gH/gL and gp42 contributed to B cell neutralization. Immunization of mice and nonhuman primates with nanoparticle vaccines that displayed components of the viral-fusion machinery EBV gH/gL or gH/gL/gp42 elicited antibodies that potently neutralized both epithelial-cell and B cell infection. Immune serum from nonhuman primates inhibited EBV-glycoprotein-mediated fusion of epithelial cells and B cells and targeted an epitope critical for virus-cell fusion. Therefore, unlike the leading EBV gp350 vaccine candidate, which only protects B cells from infection, these EBV nanoparticle vaccines elicit antibodies that inhibit the virus-fusion apparatus and provide cell-type-independent protection from virus infection.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Células Epiteliais/imunologia , Infecções por Vírus Epstein-Barr/prevenção & controle , Herpesvirus Humano 4/imunologia , Glicoproteínas de Membrana/imunologia , Proteínas do Envelope Viral/imunologia , Animais , Linfócitos B/virologia , Células CHO , Fusão Celular , Linhagem Celular Tumoral , Cricetulus , Células Epiteliais/virologia , Infecções por Vírus Epstein-Barr/imunologia , Feminino , Células HEK293 , Células HeLa , Humanos , Soros Imunes/administração & dosagem , Macaca fascicularis , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Vacinas de Partículas Semelhantes a Vírus/imunologia , Vacinas Virais/imunologia , Ligação ViralRESUMO
Epstein-Barr virus (EBV) is associated with multiple human malignancies. To evade immune detection, EBV switches between latent and lytic programs. How viral latency is maintained in tumors or in memory B cells, the reservoir for lifelong EBV infection, remains incompletely understood. To gain insights, we performed a human genome-wide CRISPR/Cas9 screen in Burkitt lymphoma B cells. Our analyses identified a network of host factors that repress lytic reactivation, centered on the transcription factor MYC, including cohesins, FACT, STAGA, and Mediator. Depletion of MYC or factors important for MYC expression reactivated the lytic cycle, including in Burkitt xenografts. MYC bound the EBV genome origin of lytic replication and suppressed its looping to the lytic cycle initiator BZLF1 promoter. Notably, MYC abundance decreases with plasma cell differentiation, a key lytic reactivation trigger. Our results suggest that EBV senses MYC abundance as a readout of B cell state and highlights Burkitt latency reversal therapeutic targets.
Assuntos
Linfoma de Burkitt/patologia , Infecções por Vírus Epstein-Barr/virologia , Herpesvirus Humano 4/fisiologia , Interações Hospedeiro-Patógeno , Proteínas Proto-Oncogênicas c-myc/metabolismo , Ativação Viral , Latência Viral , Animais , Linfócitos B/metabolismo , Linfócitos B/patologia , Linfócitos B/virologia , Linfoma de Burkitt/metabolismo , Linfoma de Burkitt/virologia , Proliferação de Células , Infecções por Vírus Epstein-Barr/genética , Infecções por Vírus Epstein-Barr/metabolismo , Feminino , Regulação Viral da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-myc/genética , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Epstein-Barr virus (EBV) is a causative agent of infectious mononucleosis and is associated with 200,000 new cases of cancer and 140,000 deaths annually. Subunit vaccines against this pathogen have focused on the gp350 glycoprotein and remain unsuccessful. We isolated human antibodies recognizing the EBV fusion machinery (gH/gL and gB) from rare memory B cells. One anti-gH/gL antibody, AMMO1, potently neutralized infection of B cells and epithelial cells, the two major cell types targeted by EBV. We determined a cryo-electron microscopy reconstruction of the gH/gL-gp42-AMMO1 complex and demonstrated that AMMO1 bound to a discontinuous epitope formed by both gH and gL at the Domain-I/Domain-II interface. Integrating structural, biochemical, and infectivity data, we propose that AMMO1 inhibits fusion of the viral and cellular membranes. This work identifies a crucial epitope that may aid in the design of next-generation subunit vaccines against this major public health burden.
Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Infecções por Vírus Epstein-Barr/imunologia , Herpesvirus Humano 4/imunologia , Glicoproteínas de Membrana/imunologia , Proteínas do Envelope Viral/imunologia , Células 3T3 , Animais , Linfócitos B/virologia , Células CHO , Linhagem Celular , Cricetulus , Microscopia Crioeletrônica , Células Epiteliais/virologia , Epitopos de Linfócito B/imunologia , Células HEK293 , Humanos , Camundongos , Ligação ViralRESUMO
Tumour-associated antigens (TAAs) comprise a large set of non-mutated cellular antigens recognized by T cells in human and murine cancers. Their potential as targets for immunotherapy has been explored for more than two decades1, yet the origins of TAA-specific T cells remain unclear. While tumour cells may be an important source of TAAs for T cell priming2, several recent studies suggest that infection with some viruses, including Epstein-Barr virus and influenza virus can elicit T cell responses against abnormally expressed cellular antigens that function as TAAs3,4. However, the cellular and molecular basis of such responses remains undefined. Here we show that expression of the Epstein-Barr virus signalling protein LMP1 in B cells provokes T cell responses to multiple TAAs. LMP1 signalling leads to overexpression of many cellular antigens previously shown to be TAAs, their presentation on major histocompatibility complex classes I (MHC-I) and II (MHC-II) (mainly through the endogenous pathway) and the upregulation of costimulatory ligands CD70 and OX40L, thereby inducing potent cytotoxic CD4+ and CD8+ T cell responses. These findings delineate a mechanism of infection-induced anti-tumour immunity. Furthermore, by ectopically expressing LMP1 in tumour B cells from patients with cancer and thereby enabling them to prime T cells, we develop a general approach for rapid production of autologous cytotoxic CD4+ T cells against a wide range of endogenous tumour antigens, such as TAAs and neoantigens, for treating B cell malignancies. This work stresses the need to revisit classical concepts concerning viral and tumour immunity, which will be critical to fully understand the impact of common infections on human health and to improve the rational design of immune approaches to treatment of cancers.
Assuntos
Linfócitos B/imunologia , Linfócitos B/virologia , Linfócitos T CD4-Positivos/imunologia , Herpesvirus Humano 4/imunologia , Neoplasias/imunologia , Neoplasias/terapia , Linfócitos T Citotóxicos/imunologia , Proteínas da Matriz Viral/imunologia , Animais , Antígenos de Neoplasias/imunologia , Ligante CD27/imunologia , Linhagem Celular Tumoral , Células Cultivadas , Feminino , Células HEK293 , Humanos , Masculino , Camundongos , Ligante OX40/imunologiaRESUMO
Epstein-Barr virus (EBV) persistently infects 95% of adults worldwide and is associated with multiple human lymphomas that express characteristic EBV latency programs used by the virus to navigate the B-cell compartment. Upon primary infection, the EBV latency III program, comprised of six Epstein-Barr Nuclear Antigens (EBNA) and two Latent Membrane Protein (LMP) antigens, drives infected B-cells into germinal center (GC). By incompletely understood mechanisms, GC microenvironmental cues trigger the EBV genome to switch to the latency II program, comprised of EBNA1, LMP1 and LMP2A and observed in GC-derived Hodgkin lymphoma. To gain insights into pathways and epigenetic mechanisms that control EBV latency reprogramming as EBV-infected B-cells encounter microenvironmental cues, we characterized GC cytokine effects on EBV latency protein expression and on the EBV epigenome. We confirmed and extended prior studies highlighting GC cytokine effects in support of the latency II transition. The T-follicular helper cytokine interleukin 21 (IL-21), which is a major regulator of GC responses, and to a lesser extent IL-4 and IL-10, hyper-induced LMP1 expression, while repressing EBNA expression. However, follicular dendritic cell cytokines including IL-15 and IL-27 downmodulate EBNA but not LMP1 expression. CRISPR editing highlighted that STAT3 and STAT5 were necessary for cytokine mediated EBNA silencing via epigenetic effects at the EBV genomic C promoter. By contrast, STAT3 was instead necessary for LMP1 promoter epigenetic remodeling, including gain of activating histone chromatin marks and loss of repressive polycomb repressive complex silencing marks. Thus, EBV has evolved to coopt STAT signaling to oppositely regulate the epigenetic status of key viral genomic promoters in response to GC cytokine cues.
Assuntos
Epigênese Genética , Infecções por Vírus Epstein-Barr , Regulação Viral da Expressão Gênica , Centro Germinativo , Herpesvirus Humano 4 , Latência Viral , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/fisiologia , Humanos , Centro Germinativo/imunologia , Centro Germinativo/virologia , Infecções por Vírus Epstein-Barr/virologia , Infecções por Vírus Epstein-Barr/genética , Infecções por Vírus Epstein-Barr/imunologia , Citocinas/metabolismo , Linfócitos B/virologia , Linfócitos B/metabolismoRESUMO
Epstein-Barr Virus (EBV) is associated with numerous cancers including B cell lymphomas. In vitro, EBV transforms primary B cells into immortalized Lymphoblastoid Cell Lines (LCLs) which serves as a model to study the role of viral proteins in EBV malignancies. EBV induced cellular transformation is driven by viral proteins including EBV-Nuclear Antigens (EBNAs). EBNA-LP is important for the transformation of naïve but not memory B cells. While EBNA-LP was thought to promote gene activation by EBNA2, EBNA-LP Knockout (LPKO) virus-infected cells express EBNA2-activated cellular genes efficiently. Therefore, a gap in knowledge exists as to what roles EBNA-LP plays in naïve B cell transformation. We developed a trans-complementation assay wherein transfection with wild-type EBNA-LP rescues the transformation of peripheral blood- and cord blood-derived naïve B cells by LPKO virus. Despite EBNA-LP phosphorylation sites being important in EBNA2 co-activation; neither phospho-mutant nor phospho-mimetic EBNA-LP was defective in rescuing naïve B cell outgrowth. However, we identified conserved leucine-rich motifs in EBNA-LP that were required for transformation of adult naïve and cord blood B cells. Because cellular PPAR-g coactivator (PGC) proteins use leucine-rich motifs to engage transcription factors including YY1, a key regulator of DNA looping and metabolism, we examined the role of EBNA-LP in engaging transcription factors. We found a significant overlap between EBNA-LP and YY1 in ChIP-Seq data. By Cut&Run, YY1 peaks unique to WT compared to LPKO LCLs occur at more highly expressed genes. Moreover, Cas9 knockout of YY1 in primary B cells prior to EBV infection indicated YY1 to be important for EBV-mediated transformation. We confirmed EBNA-LP and YY1 biochemical association in LCLs by endogenous co-immunoprecipitation and found that the EBNA-LP leucine-rich motifs were required for YY1 interaction in LCLs. We propose that EBNA-LP engages YY1 through conserved leucine-rich motifs to promote EBV transformation of naïve B cells.
Assuntos
Linfócitos B , Transformação Celular Viral , Herpesvirus Humano 4 , Proteínas Virais , Fator de Transcrição YY1 , Humanos , Linfócitos B/virologia , Linfócitos B/metabolismo , Linfócitos B/imunologia , Fator de Transcrição YY1/metabolismo , Proteínas Virais/metabolismo , Proteínas Virais/genética , Infecções por Vírus Epstein-Barr/virologia , Infecções por Vírus Epstein-Barr/metabolismo , Infecções por Vírus Epstein-Barr/imunologia , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Antígenos Nucleares do Vírus Epstein-Barr/genética , Motivos de Aminoácidos , Leucina/metabolismoRESUMO
Epstein-Barr virus (EBV) is an important cause of human lymphomas, including Burkitt lymphoma (BL). EBV+ BLs are driven by Myc translocation and have stringent forms of viral latency that do not express either of the two major EBV oncoproteins, EBNA2 (which mimics Notch signaling) and LMP1 (which activates NF-κB signaling). Suppression of Myc-induced apoptosis, often through mutation of the TP53 (p53) gene or inhibition of pro-apoptotic BCL2L11 (BIM) gene expression, is required for development of Myc-driven BLs. EBV+ BLs contain fewer cellular mutations in apoptotic pathways compared to EBV-negative BLs, suggesting that latent EBV infection inhibits Myc-induced apoptosis. Here we use an EBNA2-deleted EBV virus (ΔEBNA2 EBV) to create the first in vivo model for EBV+ BL-like lymphomas derived from primary human B cells. We show that cord blood B cells infected with both ΔEBNA2 EBV and a Myc-expressing vector proliferate indefinitely on a CD40L/IL21 expressing feeder layer in vitro and cause rapid onset EBV+ BL-like tumors in NSG mice. These LMP1/EBNA2-negative Myc-driven lymphomas have wild type p53 and very low BIM, and express numerous germinal center B cell proteins (including TCF3, BACH2, Myb, CD10, CCDN3, and GCSAM) in the absence of BCL6 expression. Myc-induced activation of Myb mediates expression of many of these BL-associated proteins. We demonstrate that Myc blocks LMP1 expression both by inhibiting expression of cellular factors (STAT3 and Src) that activate LMP1 transcription and by increasing expression of proteins (DNMT3B and UHRF1) known to enhance DNA methylation of the LMP1 promoters in human BLs. These results show that latent EBV infection collaborates with Myc over-expression to induce BL-like human B-cell lymphomas in mice. As NF-κB signaling retards the growth of EBV-negative BLs, Myc-mediated repression of LMP1 may be essential for latent EBV infection and Myc translocation to collaboratively induce human BLs.
Assuntos
Linfócitos B , Linfoma de Burkitt , Infecções por Vírus Epstein-Barr , Herpesvirus Humano 4 , Proteínas Proto-Oncogênicas c-myc , Latência Viral , Animais , Linfoma de Burkitt/virologia , Linfoma de Burkitt/metabolismo , Linfoma de Burkitt/patologia , Linfoma de Burkitt/genética , Humanos , Camundongos , Infecções por Vírus Epstein-Barr/virologia , Infecções por Vírus Epstein-Barr/metabolismo , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/genética , Herpesvirus Humano 4/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Linfócitos B/virologia , Linfócitos B/metabolismo , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Antígenos Nucleares do Vírus Epstein-Barr/genética , Apoptose , Proteínas Virais/metabolismo , Proteínas Virais/genéticaRESUMO
Epstein-Barr virus (EBV) is a human tumor virus associated with a variety of malignancies, including nasopharyngeal carcinoma, gastric cancers, and B-cell lymphomas. N6-methyladenosine (m6A) modifications modulate a wide range of cellular processes and participate in the regulation of virus-host cell interactions. Here, we discovered that EBV infection downregulates toll-like receptor 9 (TLR9) m6A modification levels and thus inhibits TLR9 expression. TLR9 has multiple m6A modification sites. Knockdown of METTL3, an m6A "writer", decreases TLR9 protein expression by inhibiting its mRNA stability. Mechanistically, Epstein-Barr nuclear antigen 1 increases METTL3 protein degradation via K48-linked ubiquitin-proteasome pathway. Additionally, YTHDF1 was identified as an m6A "reader" of TLR9, enhancing TLR9 expression by promoting mRNA translation in an m6A -dependent manner, which suggests that EBV inhibits TLR9 translation by "hijacking" host m6A modification mechanism. Using the METTL3 inhibitor STM2457 inhibits TLR9-induced B cell proliferation and immunoglobulin secretion, and opposes TLR9-induced immune responses to assist tumor cell immune escape. In clinical lymphoma samples, the expression of METTL3, YTHDF1, and TLR9 was highly correlated with immune cells infiltration. This study reveals a novel mechanism that EBV represses the important innate immunity molecule TLR9 through modulating the host m6A modification system.
Assuntos
Adenosina , Herpesvirus Humano 4 , Metiltransferases , Proteínas de Ligação a RNA , Receptor Toll-Like 9 , Humanos , Adenosina/análogos & derivados , Adenosina/metabolismo , Linfócitos B/metabolismo , Linfócitos B/imunologia , Linfócitos B/virologia , Infecções por Vírus Epstein-Barr/imunologia , Infecções por Vírus Epstein-Barr/metabolismo , Infecções por Vírus Epstein-Barr/virologia , Infecções por Vírus Epstein-Barr/genética , Herpesvirus Humano 4/imunologia , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/metabolismo , Evasão da Resposta Imune , Metiltransferases/metabolismo , Metiltransferases/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/imunologia , Receptor Toll-Like 9/metabolismo , Receptor Toll-Like 9/genética , Linhagem Celular TumoralRESUMO
Equine herpesvirus type 1 (EHV-1) is a contagious respiratory pathogen that infects the mucosa of the upper respiratory tract (URT). Mucosal immune responses at the URT provide the first line of defense against EHV-1 and are crucial for orchestrating immunity. To define host-pathogen interactions, we characterized B-cell responses, antibody isotype functions, and EHV-1 replication of susceptible (non-immune) and clinically protected (immune) horses after experimental EHV-1 infection. Nasal secretion and nasal wash samples were collected and used for the isolation of DNA, RNA, and mucosal antibodies. Shedding of infectious virus, EHV-1 copy numbers, viral RNA expression, and host B-cell activation in the URT were compared based on host immune status. Mucosal EHV-1-specific antibody responses were associated with EHV-1 shedding and viral RNA transcription. Finally, mucosal immunoglobulin G (IgG) and IgA isotypes were purified and tested for neutralizing capabilities. IgG1 and IgG4/7 neutralized EHV-1, while IgG3/5, IgG6, and IgA did not. Immune horses secreted high amounts of mucosal EHV-1-specific IgG4/7 antibodies and quickly upregulated B-cell pathway genes, while EHV-1 was undetected by virus isolation and PCR. RNA transcription analysis reinforced incomplete viral replication in immune horses. In contrast, complete viral replication with high viral copy numbers and shedding of infectious viruses was characteristic for non-immune horses, together with low or absent EHV-1-specific neutralizing antibodies during viral replication. These data confirm that pre-existing mucosal IgG1 and IgG4/7 and rapid B-cell activation upon EHV-1 infection are essential for virus neutralization, regulation of viral replication, and mucosal immunity against EHV-1.IMPORTANCEEquine herpesvirus type 1 (EHV-1) causes respiratory disease, abortion storms, and neurologic outbreaks known as equine herpes myeloencephalopathy (EHM). EHV-1 is transmitted with respiratory secretions by nose-to-nose contact or via fomites. The virus initially infects the epithelium of the upper respiratory tract (URT). Host-pathogen interactions and mucosal immunity at the viral entry site provide the first line of defense against the EHV-1. Robust mucosal immunity can be essential in protecting against EHV-1 and to reduce EHM outbreaks. It has previously been shown that immune horses do not establish cell-associated viremia, the prerequisite for EHM. Here, we demonstrate how mucosal antibodies can prevent the replication of EHV-1 at the epithelium of the URT and, thereby, the progression of the virus to the peripheral blood. The findings improve the mechanistic understanding of mucosal immunity against EHV-1 and can support the development of enhanced diagnostic tools, vaccines against EHM, and the management of EHV-1 outbreaks.
Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , Infecções por Herpesviridae , Herpesvirus Equídeo 1 , Doenças dos Cavalos , Imunoglobulina G , Replicação Viral , Animais , Herpesvirus Equídeo 1/imunologia , Cavalos , Infecções por Herpesviridae/imunologia , Infecções por Herpesviridae/veterinária , Infecções por Herpesviridae/virologia , Anticorpos Antivirais/imunologia , Anticorpos Neutralizantes/imunologia , Doenças dos Cavalos/virologia , Doenças dos Cavalos/imunologia , Imunoglobulina G/imunologia , Imunidade nas Mucosas , Eliminação de Partículas Virais/imunologia , Linfócitos B/imunologia , Linfócitos B/virologia , Interações Hospedeiro-Patógeno/imunologiaRESUMO
Most mature B-cell malignancies originate from the malignant transformation of germinal center (GC) B cells. The GC reaction appears to have a role in malignant transformation, in which a major player of the GC reaction is BCL6, a key regulator of this process. We now demonstrate that BCL6 protein levels were dramatically decreased in Epstein-Barr virus (EBV)-positive lymphoblastoid cell lines and Burkitt's lymphoma cell lines. Notably, BCL6 degradation was significantly enhanced in the presence of both EBNA3C and FBXO11. Furthermore, the amino-terminal domain of EBNA3C, which contains residues 50-100, interacts directly with FBXO11. The expression of EBNA3C and FBXO11 resulted in a significant induction of cell proliferation. Furthermore, BCL6 protein expression levels were regulated by EBNA3C via the Skp Cullin Fbox (SCF)FBXO11 complex, which mediated its ubiquitylation, and knockdown of FBXO11 suppressed the transformation of lymphoblastoid cell lines. These data provide new insights into the function of EBNA3C in B-cell transformation during GC reaction and raise the possibility of developing new targeted therapies against EBV-associated cancers. IMPORTANCE: The novel revelation in our study involves the suppression of BCL6 expression by the essential Epstein-Barr virus (EBV) antigen EBNA3C, shedding new light on our current comprehension of how EBV contributes to lymphomagenesis by impeding the germinal center reaction. It is crucial to note that while several EBV latent proteins are expressed in infected cells, the collaborative mechanisms among these proteins in regulating B-cell development or inducing B-cell lymphoma require additional investigation. Nonetheless, our findings carry significance for the development of emerging strategies aimed at addressing EBV-associated cancers.
Assuntos
Antígenos Nucleares do Vírus Epstein-Barr , Proteínas F-Box , Herpesvirus Humano 4 , Proteínas Proto-Oncogênicas c-bcl-6 , Humanos , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Antígenos Nucleares do Vírus Epstein-Barr/genética , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , Proteínas Proto-Oncogênicas c-bcl-6/genética , Proteínas F-Box/metabolismo , Proteínas F-Box/genética , Herpesvirus Humano 4/metabolismo , Herpesvirus Humano 4/genética , Linhagem Celular Tumoral , Linfócitos B/metabolismo , Linfócitos B/virologia , Infecções por Vírus Epstein-Barr/metabolismo , Infecções por Vírus Epstein-Barr/virologia , Proteólise , Proliferação de Células , Ubiquitinação , Linfoma de Burkitt/virologia , Linfoma de Burkitt/metabolismo , Linfoma de Burkitt/genética , Linfoma de Burkitt/patologia , Antígenos Virais/metabolismo , Antígenos Virais/genética , Centro Germinativo/metabolismo , Centro Germinativo/virologia , Proteína-Arginina N-MetiltransferasesRESUMO
AIDS-defining cancers declined after combined antiretroviral therapy (cART) introduction, but lymphomas are still elevated in HIV type 1 (HIV-1)-infected patients. In particular, non-Hodgkin's lymphomas (NHLs) represent the majority of all AIDS-defining cancers and are the most frequent cause of death in these patients. We have recently demonstrated that amino acid (aa) insertions at the HIV-1 matrix protein p17 COOH-terminal region cause protein destabilization, leading to conformational changes. Misfolded p17 variants (vp17s) strongly impact clonogenic B cell growth properties that may contribute to B cell lymphomagenesis as suggested by the significantly higher frequency of detection of vp17s with COOH-terminal aa insertions in plasma of HIV-1-infected patients with NHL. Here, we expand our previous observations by assessing the prevalence of vp17s in large retrospective cohorts of patients with and without lymphoma. We confirm the significantly higher prevalence of vp17s in lymphoma patients than in HIV-1-infected individuals without lymphoma. Analysis of 3,990 sequences deposited between 1985 and 2017 allowed us to highlight a worldwide increasing prevalence of HIV-1 mutants expressing vp17s over time. Since genomic surveillance uncovered a cluster of HIV-1 expressing a B cell clonogenic vp17 dated from 2011 to 2019, we conclude that aa insertions can be fixed in HIV-1 and that mutant viruses displaying B cell clonogenic vp17s are actively spreading.
Assuntos
Linfócitos B , Antígenos HIV , HIV-1 , Linfoma Relacionado a AIDS , Produtos do Gene gag do Vírus da Imunodeficiência Humana , Linfócitos B/virologia , Variação Genética , Antígenos HIV/genética , HIV-1/genética , HIV-1/isolamento & purificação , Humanos , Linfoma Relacionado a AIDS/epidemiologia , Linfoma Relacionado a AIDS/virologia , Prevalência , Estudos Retrospectivos , Produtos do Gene gag do Vírus da Imunodeficiência Humana/genéticaRESUMO
SignificanceEpstein-Barr virus (EBV) contributes to Burkitt lymphoma and post-transplant lymphoproliferative disease (PTLD). EBV-transforming programs activate lipid metabolism to convert B cells into immortalized lymphoblastoid cell lines (LCL), a PTLD model. We found that stages of EBV transformation generate lipid reactive oxygen species (ROS) byproducts to varying degrees, and that a Burkitt-like phase of B cell outgrowth requires lipid ROS detoxification by glutathione peroxidase 4 and its cofactor glutathione. Perturbation of this redox defense in early stages of transformation or in Burkitt cells triggered ferroptosis, a programmed cell death pathway. LCLs were less dependent on this defense, a distinction tied to EBV latency programs. This highlights ferroptosis induction as a potential therapeutic approach for prevention or treatment of certain EBV+ lymphomas.
Assuntos
Linfócitos B , Linfoma de Burkitt , Transformação Celular Viral , Ferroptose , Herpesvirus Humano 4 , Latência Viral , Linfócitos B/imunologia , Linfócitos B/virologia , Linfoma de Burkitt/virologia , Ferroptose/imunologia , Herpesvirus Humano 4/fisiologia , Humanos , Metabolismo dos Lipídeos , Ativação Linfocitária , Espécies Reativas de Oxigênio/metabolismoRESUMO
The germinal center (GC) plays a central role in the generation of antigen-specific B cells and antibodies. Tight regulation of the GC is essential due to the inherent risks of tumorigenesis and autoimmunity posed by inappropriate GC B cell processes. Gammaherpesviruses such as Epstein-Barr virus (EBV) and murine gammaherpesvirus 68 (MHV68) utilize numerous armaments to drive infected naïve B cells, independent of antigen, through GC reactions to expand the latently infected B cell population and establish a stable latency reservoir. We previously demonstrated that the MHV68 microRNA (miRNA) mghv-miR-M1-7-5p represses host EWSR1 (Ewing sarcoma breakpoint region 1) to promote B cell infection. EWSR1 is a transcription and splicing regulator that is recognized for its involvement as a fusion protein in Ewing sarcoma. A function for EWSR1 in B cell responses has not been previously reported. Here, we demonstrate that 1) B cell-specific deletion of EWSR1 had no effect on generation of mature B cell subsets or basal immunoglobulin levels in naïve mice, 2) repression or ablation of EWSR1 in B cells promoted expansion of MHV68 latently infected GC B cells, and 3) B cell-specific deletion of EWSR1 during a normal immune response to nonviral antigen resulted in significantly elevated numbers of antigen-specific GC B cells, plasma cells, and circulating antibodies. Notably, EWSR1 deficiency did not affect the proliferation or survival of GC B cells but instead resulted in the generation of increased numbers of precursor GC B cells. Cumulatively, these findings demonstrate that EWSR1 is a negative regulator of B cell responses.
Assuntos
Linfócitos B , Gammaherpesvirinae , Centro Germinativo , Infecções por Herpesviridae , MicroRNAs , Proteína EWS de Ligação a RNA , Infecções Tumorais por Vírus , Animais , Linfócitos B/imunologia , Linfócitos B/virologia , Gammaherpesvirinae/genética , Gammaherpesvirinae/fisiologia , Deleção de Genes , Centro Germinativo/imunologia , Centro Germinativo/virologia , Infecções por Herpesviridae/genética , Infecções por Herpesviridae/imunologia , Infecções por Herpesviridae/virologia , Camundongos , MicroRNAs/genética , MicroRNAs/metabolismo , Proteína EWS de Ligação a RNA/genética , Proteína EWS de Ligação a RNA/metabolismo , Infecções Tumorais por Vírus/genética , Infecções Tumorais por Vírus/imunologia , Infecções Tumorais por Vírus/virologia , Latência ViralRESUMO
Epstein-Barr virus (EBV) is a human tumor virus which preferentially infects resting human B cells. Upon infection in vitro, EBV activates and immortalizes these cells. The viral latent protein EBV nuclear antigen 2 (EBNA2) is essential for B cell activation and immortalization; it targets and binds the cellular and ubiquitously expressed DNA-binding protein CBF1, thereby transactivating a plethora of viral and cellular genes. In addition, EBNA2 uses its N-terminal dimerization (END) domain to bind early B cell factor 1 (EBF1), a pioneer transcription factor specifying the B cell lineage. We found that EBNA2 exploits EBF1 to support key metabolic processes and to foster cell cycle progression of infected B cells in their first cell cycles upon activation. The α1-helix within the END domain was found to promote EBF1 binding. EBV mutants lacking the α1-helix in EBNA2 can infect and activate B cells efficiently, but activated cells fail to complete the early S phase of their initial cell cycle. Expression of MYC, target genes of MYC and E2F, as well as multiple metabolic processes linked to cell cycle progression are impaired in EBVΔα1-infected B cells. Our findings indicate that EBF1 controls B cell activation via EBNA2 and, thus, has a critical role in regulating the cell cycle of EBV-infected B cells. This is a function of EBF1 going beyond its well-known contribution to B cell lineage specification.