RESUMO
Viral mutations are an emerging concern in reducing SARS-CoV-2 vaccination efficacy. Second-generation vaccines will need to elicit neutralizing antibodies against sites that are evolutionarily conserved across the sarbecovirus subgenus. Here, we immunized mice containing a human antibody repertoire with diverse sarbecovirus receptor-binding domains (RBDs) to identify antibodies targeting conserved sites of vulnerability. Antibodies with broad reactivity against diverse clade B RBDs targeting the conserved class 4 epitope, with recurring IGHV/IGKV pairs, were readily elicited but were non-neutralizing. However, rare class 4 antibodies binding this conserved RBD supersite showed potent neutralization of SARS-CoV-2 and all variants of concern. Structural analysis revealed that the neutralizing ability of cross-reactive antibodies was reserved only for those with an elongated CDRH3 that extends the antiparallel beta-sheet RBD core and orients the antibody light chain to obstruct ACE2-RBD interactions. These results identify a structurally defined pathway for vaccine strategies eliciting escape-resistant SARS-CoV-2 neutralizing antibodies.
Assuntos
Betacoronavirus/fisiologia , Vacinas contra COVID-19/imunologia , Infecções por Coronavirus/imunologia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/fisiologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Animais , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/metabolismo , Sequência Conservada/genética , Evolução Molecular , Humanos , Imunização , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Ligação Proteica , Domínios Proteicos/genética , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Desenvolvimento de VacinasRESUMO
Natural killer (NK) cells play a critical role in virus control. However, it has remained largely unclear whether NK cell mobilization in SARS-CoV-2 infections is beneficial or pathologic. To address this deficit, we employed a validated experimental NK cell depletion non-human primate (NHP) model with SARS-CoV-2 Delta variant B.1.617.2 challenge. Viral loads (VL), NK cell numbers, activation, proliferation, and functional measures were evaluated in blood and tissues. In non-depleted (control) animals, infection rapidly induced NK cell expansion, activation, and increased tissue trafficking associated with VL. Strikingly, we report that experimental NK cell depletion leads to higher VL, longer duration of viral shedding, significantly increased levels of pro-inflammatory cytokines in the lungs, and overt lung damage. Overall, we find the first significant and conclusive evidence for NK cell-mediated control of SARS-CoV-2 virus replication and disease pathology. These data indicate that adjunct therapies for infection could largely benefit from NK cell-targeted approaches.
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The long-term health consequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are still being understood. The molecular and phenotypic properties of SARS-CoV-2 antigen-specific T cells suggest a dysfunctional profile that persists in convalescence in those who were severely ill. By contrast, the antigen-specific memory B-cell (MBC) population has not yet been analyzed to the same degree, but phenotypic analysis suggests differences following recovery from mild or severe coronavirus disease 2019 (COVID-19). Here, we performed single-cell molecular analysis of the SARS-CoV-2 receptor-binding domain (RBD)-specific MBC population in three patients after severe COVID-19 and four patients after mild/moderate COVID-19. We analyzed the transcriptomic and B-cell receptor repertoire profiles at ~2 months and ~4 months after symptom onset. Transcriptomic analysis revealed a higher level of tumor necrosis factor-alpha (TNF-α) signaling via nuclear factor-kappa B in the severe group, involving CD80, FOS, CD83 and TNFAIP3 genes that was maintained over time. We demonstrated the presence of two distinct activated MBCs subsets based on expression of CD80hi TNFAIP3hi and CD11chi CD95hi at the transcriptome level. Both groups revealed an increase in somatic hypermutation over time, indicating progressive evolution of humoral memory. This study revealed distinct molecular signatures of long-term RBD-specific MBCs in convalescence, indicating that the longevity of these cells may differ depending on acute COVID-19 severity.
Assuntos
COVID-19 , Humanos , SARS-CoV-2 , Células B de Memória , Convalescença , Anticorpos AntiviraisRESUMO
Zika virus (ZIKV) has recently emerged as a pandemic associated with severe neuropathology in newborns and adults. There are no ZIKV-specific treatments or preventatives. Therefore, the development of a safe and effective vaccine is a high priority. Messenger RNA (mRNA) has emerged as a versatile and highly effective platform to deliver vaccine antigens and therapeutic proteins. Here we demonstrate that a single low-dose intradermal immunization with lipid-nanoparticle-encapsulated nucleoside-modified mRNA (mRNA-LNP) encoding the pre-membrane and envelope glycoproteins of a strain from the ZIKV outbreak in 2013 elicited potent and durable neutralizing antibody responses in mice and non-human primates. Immunization with 30 µg of nucleoside-modified ZIKV mRNA-LNP protected mice against ZIKV challenges at 2 weeks or 5 months after vaccination, and a single dose of 50 µg was sufficient to protect non-human primates against a challenge at 5 weeks after vaccination. These data demonstrate that nucleoside-modified mRNA-LNP elicits rapid and durable protective immunity and therefore represents a new and promising vaccine candidate for the global fight against ZIKV.
Assuntos
RNA Mensageiro/administração & dosagem , RNA Mensageiro/química , Vacinas Virais/imunologia , Infecção por Zika virus/prevenção & controle , Zika virus/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Antígenos Virais/genética , Antígenos Virais/imunologia , Feminino , Glicoproteínas/genética , Glicoproteínas/imunologia , Injeções Intradérmicas , Macaca mulatta/imunologia , Macaca mulatta/virologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Nanopartículas/administração & dosagem , Nanopartículas/química , Estabilidade de RNA , RNA Mensageiro/genética , RNA Viral/administração & dosagem , RNA Viral/química , RNA Viral/genética , Fatores de Tempo , Vacinação , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/imunologia , Vacinas Virais/administração & dosagem , Zika virus/química , Zika virus/genética , Infecção por Zika virus/imunologiaRESUMO
A preventive human immunodeficiency virus type 1 (HIV-1) vaccine is an essential part of the strategy to eradicate AIDS. A critical question is whether antibodies that do not neutralize primary isolate (tier 2) HIV-1 strains can protect from infection. In this study, we investigated the ability of an attenuated poxvirus vector (NYVAC) prime-envelope gp120 boost to elicit potentially protective antibody responses in a rhesus macaque model of mucosal simian-human immunodeficiency virus (SHIV) infection. NYVAC vector delivery of a group M consensus envelope, trivalent mosaic envelopes, or a natural clade B isolate B.1059 envelope elicited antibodies that mediated neutralization of tier 1 viruses, cellular cytotoxicity, and phagocytosis. None of the macaques made neutralizing antibodies against the tier 2 SHIV SF162P3 used for mucosal challenge. Significant protection from infection was not observed for the three groups of vaccinated macaques compared to unvaccinated macaques, although binding antibody to HIV-1 Env correlated with decreased viremia after challenge. Thus, NYVAC Env prime-gp120 boost vaccination elicited polyfunctional, nonneutralizing antibody responses with minimal protective activity against tier 2 SHIV mucosal challenge.IMPORTANCE The antibody responses that confer protection against HIV-1 infection remain unknown. Polyfunctional antibody responses correlated with time to infection in previous macaque studies. Determining the ability of vaccines to induce these types of responses is critical for understanding how to improve upon the one efficacious human HIV-1 vaccine trial completed thus far. We characterized the antibody responses induced by a NYVAC-protein vaccine and determined the protective capacity of polyfunctional antibody responses in an R5, tier 2 mucosal SHIV infection model.
Assuntos
Vacinas contra a AIDS/imunologia , HIV-1/imunologia , Imunização Secundária , Imunogenicidade da Vacina , Vírus da Imunodeficiência Símia/imunologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Animais , Humanos , Macaca mulattaRESUMO
The design of an effective HIV-1 vaccine remains a major challenge. Several vaccine strategies based on viral vectors have been evaluated in preclinical and clinical trials, with largely disappointing results. Integrase defective lentiviral vectors (IDLV) represent a promising vaccine candidate given their ability to induce durable and protective immune responses in mice after a single immunization. Here, we evaluated the immunogenicity of a SIV-based IDLV in nonhuman primates. Six rhesus monkeys were primed intramuscularly with IDLV-Env and boosted with the same vector after 1 year. A single immunization with IDLV-Env induced broad humoral and cellular immune responses that waned over time but were still detectable at 1 year postprime. The boost with IDLV-Env performed at 1 year from the prime induced a remarkable increase in both antibodies and T-cell responses. Antibody binding specificity showed a predominant cross-clade gp120-directed response. Monkeys' sera efficiently blocked anti-V2 and anti-CD4 binding site antibodies, neutralized the tier 1 MW965.26 pseudovirus and mediated antibody-dependent cellular cytotoxicity (ADCC). Durable polyfunctional Env-specific T-cell responses were also elicited. Our study demonstrates that an IDLV-Env-based vaccine induces functional, comprehensive, and durable immune responses in Rhesus macaques. These results support further evaluation of IDLV as a new HIV-1 vaccine delivery platform.
Assuntos
Vacinas contra a AIDS/administração & dosagem , Integrases/deficiência , Vírus da Imunodeficiência Símia/genética , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Vacinas contra a AIDS/imunologia , Animais , Imunidade Celular , Imunização Secundária , Injeções Intramusculares , Macaca mulatta , Linfócitos T/metabolismo , Vacinação/métodos , Produtos do Gene env do Vírus da Imunodeficiência Humana/genéticaRESUMO
UNLABELLED: An effective human immunodeficiency virus type 1 (HIV-1) vaccine must induce protective antibody responses, as well as CD4(+) and CD8(+) T cell responses, that can be effective despite extraordinary diversity of HIV-1. The consensus and mosaic immunogens are complete but artificial proteins, computationally designed to elicit immune responses with improved cross-reactive breadth, to attempt to overcome the challenge of global HIV diversity. In this study, we have compared the immunogenicity of a transmitted-founder (T/F) B clade Env (B.1059), a global group M consensus Env (Con-S), and a global trivalent mosaic Env protein in rhesus macaques. These antigens were delivered using a DNA prime-recombinant NYVAC (rNYVAC) vector and Env protein boost vaccination strategy. While Con-S Env was a single sequence, mosaic immunogens were a set of three Envs optimized to include the most common forms of potential T cell epitopes. Both Con-S and mosaic sequences retained common amino acids encompassed by both antibody and T cell epitopes and were central to globally circulating strains. Mosaics and Con-S Envs expressed as full-length proteins bound well to a number of neutralizing antibodies with discontinuous epitopes. Also, both consensus and mosaic immunogens induced significantly higher gamma interferon (IFN-γ) enzyme-linked immunosorbent spot assay (ELISpot) responses than B.1059 immunogen. Immunization with these proteins, particularly Con-S, also induced significantly higher neutralizing antibodies to viruses than B.1059 Env, primarily to tier 1 viruses. Both Con-S and mosaics stimulated more potent CD8-T cell responses against heterologous Envs than did B.1059. Both antibody and cellular data from this study strengthen the concept of using in silico-designed centralized immunogens for global HIV-1 vaccine development strategies. IMPORTANCE: There is an increasing appreciation for the importance of vaccine-induced anti-Env antibody responses for preventing HIV-1 acquisition. This nonhuman primate study demonstrates that in silico-designed global HIV-1 immunogens, designed for a human clinical trial, are capable of eliciting not only T lymphocyte responses but also potent anti-Env antibody responses.
Assuntos
HIV-1/imunologia , Vacinas contra a SAIDS/imunologia , Vacinação/métodos , Vacinas de DNA/imunologia , Animais , Anticorpos Neutralizantes/sangue , Antígenos Virais/genética , Antígenos Virais/imunologia , Aspartato Aminotransferases , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Sequência Consenso , ELISPOT , Anticorpos Anti-HIV/sangue , HIV-1/genética , Humanos , Interferon gama/metabolismo , Macaca mulatta , Vacinas contra a SAIDS/administração & dosagem , Vacinas contra a SAIDS/genética , Vacinas de DNA/administração & dosagem , Vacinas de DNA/genética , Vacinas de Subunidades Antigênicas/administração & dosagem , Vacinas de Subunidades Antigênicas/genética , Vacinas de Subunidades Antigênicas/imunologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologiaRESUMO
Immunoglobulin A (IgA) is the predominant mucosal antibody class with both anti- and pro-inflammatory roles1-3. However, the specific role of the IgA receptor cluster of differentiation (CD)89, expressed by a subset of natural killer (NK) cells, is poorly explored. We found that CD89 protein expression on circulating NK cells is infrequent in humans and rhesus macaques, but transcriptomic analysis showed ubiquitous CD89 expression, suggesting an inducible phenotype. Interestingly, CD89+ NK cells were more frequent in cord blood and mucosae, indicating a putative IgA-mediated NK cell function in the mucosae and infant immune system. CD89+ NK cells signaled through upregulated CD3 zeta chain (CD3ζ), spleen tyrosine kinase (Syk), zeta chain-associated protein kinase 70 (ZAP70), and signaling lymphocytic activation molecule family 1 (SLAMF1), but also showed high expression of inhibitory receptors such as killer cell lectin-like receptor subfamily G (KLRG1) and reduced activating NKp46 and NKp30. CD89-based activation or antibody-mediated cellular cytotoxicity with monomeric IgA1 reduced NK cell functions, while antibody-mediated cellular cytotoxicity with combinations of IgG and IgA2 was enhanced compared to IgG alone. These data suggest that functional CD89+ NK cells survey mucosal sites, but CD89 likely serves as regulatory receptor which can be further modulated depending on IgA and IgG subclass. Although the full functional niche of CD89+ NK cells remains unexplored, these intriguing data suggest the CD89 axis could represent a novel immunotherapeutic target in the mucosae or early life.
Assuntos
Imunoglobulina A , Células Matadoras Naturais , Macaca mulatta , Transdução de Sinais , Família de Moléculas de Sinalização da Ativação Linfocitária , Humanos , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Animais , Imunoglobulina A/metabolismo , Imunoglobulina A/imunologia , Família de Moléculas de Sinalização da Ativação Linfocitária/metabolismo , Família de Moléculas de Sinalização da Ativação Linfocitária/genética , Receptores Fc/metabolismo , Receptores Fc/genética , Mucosa/imunologia , Mucosa/metabolismo , Regulação para Cima , Imunidade nas Mucosas , Citotoxicidade Imunológica , Células Cultivadas , Antígenos CDRESUMO
Multifaceted natural killer (NK) cell activities are indispensable for controlling human immunodeficiency virus (HIV)-1 transmission and pathogenesis. Among the diverse functions of NK cells, antibody-dependent cellular cytotoxicity (ADCC) has been shown to predict better HIV-1 protection. ADCC is initiated by the engagement of an Fc γ receptor CD16 with an Fc portion of the antibody, leading to phosphorylation of the CD3 ζ chain (CD3ζ) and Fc receptor γ chain (FcRγ) as well as downstream signaling activation. Though CD3ζ and FcRγ were thought to have overlapping roles in NK cell ADCC, several groups have reported that CD3ζ-mediated signals trigger a more robust ADCC. However, few studies have illustrated the direct contribution of CD3ζ in HIV-1-specific ADCC. To further understand the roles played by CD3ζ in HIV-1-specific ADCC, we developed a CD3ζ knockdown system in primary human NK cells. We observed that HIV-1-specific ADCC was inhibited by CD3ζ perturbation. In summary, we demonstrated that CD3ζ is important for eliciting HIV-1-specific ADCC, and this dynamic can be utilized for NK cell immunotherapeutics against HIV-1 infection and other diseases.
RESUMO
Emerging variants of concern (VOCs) are threatening to limit the effectiveness of SARS-CoV-2 monoclonal antibodies and vaccines currently used in clinical practice; broadly neutralizing antibodies and strategies for their identification are therefore urgently required. Here we demonstrate that broadly neutralizing antibodies can be isolated from peripheral blood mononuclear cells of convalescent patients using SARS-CoV-2 receptor binding domains carrying epitope-specific mutations. This is exemplified by two human antibodies, GAR05, binding to epitope class 1, and GAR12, binding to a new epitope class 6 (located between class 3 and 5). Both antibodies broadly neutralize VOCs, exceeding the potency of the clinical monoclonal sotrovimab (S309) by orders of magnitude. They also provide prophylactic and therapeutic in vivo protection of female hACE2 mice against viral challenge. Our results indicate that exposure to SARS-CoV-2 induces antibodies that maintain broad neutralization against emerging VOCs using two unique strategies: either by targeting the divergent class 1 epitope in a manner resistant to VOCs (ACE2 mimicry, as illustrated by GAR05 and mAbs P2C-1F11/S2K14); or alternatively, by targeting rare and highly conserved epitopes, such as the new class 6 epitope identified here (as illustrated by GAR12). Our results provide guidance for next generation monoclonal antibody development and vaccine design.
Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Feminino , Animais , Camundongos , Anticorpos Amplamente Neutralizantes , Leucócitos Mononucleares , Anticorpos Antivirais , Anticorpos Monoclonais , Anticorpos Neutralizantes , Epitopos , Glicoproteína da Espícula de Coronavírus/genética , Testes de NeutralizaçãoRESUMO
One of the most puzzling observations in HIV research is the lack of pathogenicity in most nonhuman primate species that are natural hosts of simian immunodeficiency virus (SIV) infection. Despite this, natural hosts experience a level of viremia similar to humans infected with HIV or macaques infected with SIV. To determine the role of adaptive immune responses in viral containment and lack of disease, we delayed the generation of cellular and humoral immune responses by administering anti-CD8- and anti-CD20 lymphocyte-depleting antibodies to sabaeus African green monkeys (Chlorocebus sabaeus) before challenge with SIV(sab9315BR). In vivo lymphocyte depletion during primary infection resulted in a brief elevation of viremia but not in disease. Based on the magnitude and timing of SIV-specific CD8(+) T-cell responses in the lymphocyte-depleted animals, CD8(+) T-cell responses appear to contribute to viral containment in natural hosts. We found no evidence for a contribution of humoral immune responses in viral containment. These studies indicate that natural hosts have developed mechanisms in addition to classic adaptive immune responses to cope with this lentiviral infection. Thus, adaptive immune responses in natural hosts appear to be less critical for viral containment than in HIV infection.
Assuntos
Imunidade Adaptativa/imunologia , Chlorocebus aethiops/imunologia , Chlorocebus aethiops/virologia , Terapia de Imunossupressão , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Viremia/prevenção & controle , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Murinos , Anticorpos Neutralizantes/biossíntese , Antígenos CD20/metabolismo , Contagem de Linfócito CD4 , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD4-Positivos/virologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Linfócitos T CD8-Positivos/virologia , Humanos , Imunidade Celular/imunologia , Imunidade Humoral/imunologia , Memória Imunológica/imunologia , Interferon gama/imunologia , Antígeno Ki-67/metabolismo , Depleção Linfocítica , Tecido Linfoide/imunologia , Rituximab , Síndrome de Imunodeficiência Adquirida dos Símios/tratamento farmacológico , Síndrome de Imunodeficiência Adquirida dos Símios/prevenção & controle , Vírus da Imunodeficiência Símia , Fatores de Tempo , Viremia/imunologia , Viremia/virologiaRESUMO
Coronavirus disease 2019 (COVID-19) convalescents living in regions with low vaccination rates rely on post-infection immunity for protection against re-infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We evaluate humoral and T cell immunity against five variants of concern (VOCs) in mild-COVID-19 convalescents at 12 months after infection with ancestral virus. In this cohort, ancestral, receptor-binding domain (RBD)-specific antibody and circulating memory B cell levels are conserved in most individuals, and yet serum neutralization against live B.1.1.529 (Omicron) is completely abrogated and significantly reduced for other VOCs. Likewise, ancestral SARS-CoV-2-specific memory T cell frequencies are maintained in >50% of convalescents, but the cytokine response in these cells to mutated spike epitopes corresponding to B.1.1.529 and B.1.351 (Beta) VOCs were impaired. These results indicate that increased antigen variability in VOCs impairs humoral and spike-specific T cell immunity post-infection, strongly suggesting that COVID-19 convalescents are vulnerable and at risk of re-infection with VOCs, thus stressing the importance of vaccination programs.
Assuntos
COVID-19 , Linfócitos T , Anticorpos Neutralizantes , Anticorpos Antivirais , Humanos , Reinfecção , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/genéticaRESUMO
Understanding the long-term maintenance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunity is critical for predicting protection against reinfection. In an age- and gender-matched cohort of 24 participants, the association of disease severity and early immune responses on the maintenance of humoral immunity 12 months post-infection is examined. All severely affected participants maintain a stable subset of SARS-CoV-2 receptor-binding domain (RBD)-specific memory B cells (MBCs) and good neutralizing antibody breadth against the majority of the variants of concern, including the Delta variant. Modeling these immune responses against vaccine efficacy data indicate a 45%-76% protection against symptomatic infection (variant dependent). Overall, these findings indicate durable humoral responses in most participants after infection, reasonable protection against reinfection, and implicate baseline antigen-specific CD4+ T cell responses as a predictor of maintenance of antibody neutralization breadth and RBD-specific MBC levels at 12 months post-infection.
Assuntos
Anticorpos Amplamente Neutralizantes/metabolismo , Células B de Memória/metabolismo , SARS-CoV-2/imunologia , Adulto , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Austrália , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , COVID-19/imunologia , Estudos de Coortes , Feminino , Humanos , Imunidade/imunologia , Imunidade Humoral/imunologia , Masculino , Células B de Memória/imunologia , SARS-CoV-2/patogenicidade , Índice de Gravidade de Doença , Glicoproteína da Espícula de Coronavírus/imunologiaRESUMO
It has been suggested that vaccination prior to infection may direct the mutational evolution of human immunodeficiency virus type 1 (HIV-1) to a less fit virus, resulting in an attenuated course of disease. The present study was initiated to explore whether prior immunization might prevent the reversion of the virus to the wild-type form. Mamu-A*01 monkeys were vaccinated to generate a cytotoxic T-lymphocyte response to the immunodominant Gag p11C epitope and were then challenged with a cloned pathogenic CXCR4-tropic simian-human immunodeficiency virus (SHIV) expressing a mutant Gag p11C sequence (Δp11C SHIV). The epitopic and extraepitopic compensatory mutations introduced into gag of Δp11C SHIV resulted in attenuated replicative capacity and eventual reversions to the wild-type Gag p11C sequence in naïve rhesus monkeys. However, in vaccinated rhesus monkeys, no reversions of the challenge virus were observed, an effect that may have been a consequence of significantly decreased viral replication rather than a redirection of the mutational evolution of the virus. These findings highlight the multifactorial pressures that affect the evolution of primate immunodeficiency viruses.
Assuntos
Vacinas contra a SAIDS/uso terapêutico , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/prevenção & controle , Vírus da Imunodeficiência Símia/fisiologia , Replicação Viral/genética , Sequência de Aminoácidos , Animais , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/virologia , Epitopos de Linfócito T/imunologia , Citometria de Fluxo , Produtos do Gene gag/genética , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Macaca mulatta , Dados de Sequência Molecular , Mutação Puntual , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência de Aminoácidos , Síndrome de Imunodeficiência Adquirida dos Símios/genética , Vírus da Imunodeficiência Símia/genética , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/virologia , Vacinação , Carga ViralRESUMO
Considerable concerns relating to the duration of protective immunity against severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) exist, with evidence of antibody titers declining rapidly after infection and reports of reinfection. Here, we monitor the antibody responses against SARS-CoV-2 receptor-binding domain (RBD) for up to 6 months after infection. While antibody titers are maintained, â¼13% of the cohort's neutralizing responses return to background. However, encouragingly, in a selected subset of 13 participants, 12 have detectable RBD-specific memory B cells and these generally are increasing out to 6 months. Furthermore, we are able to generate monoclonal antibodies with SARS-CoV-2 neutralizing capacity from these memory B cells. Overall, our study suggests that the loss of neutralizing antibodies in plasma may be countered by the maintenance of neutralizing capacity in the memory B cell repertoire.
Assuntos
Anticorpos Neutralizantes/sangue , COVID-19/patologia , Células B de Memória/metabolismo , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Neutralizantes/imunologia , Doenças Assintomáticas , COVID-19/imunologia , COVID-19/virologia , Feminino , Humanos , Limite de Detecção , Masculino , Pessoa de Meia-Idade , Testes de Neutralização , Domínios Proteicos/imunologia , SARS-CoV-2/isolamento & purificação , Índice de Gravidade de Doença , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Fatores de Tempo , Adulto JovemRESUMO
While mycobacteria have been proposed as vaccine vectors because of their persistence and safety, little has been done systematically to optimize their immunogenicity in nonhuman primates. We successfully generated recombinant Mycobacterium bovis BCG (rBCG) expressing simian immunodeficiency virus (SIV) Gag and Pol as multigenic, nonintegrating vectors, but rBCG-expressing SIV Env was unstable. A dose and route determination study in rhesus monkeys revealed that intramuscular administration of rBCG was associated with local reactogenicity, whereas intravenous and intradermal administration of 10(6) to 10(8) CFU of rBCG was well tolerated. After single or repeat rBCG inoculations, monkeys developed high-frequency gamma interferon enzyme-linked immunospot responses against BCG purified protein derivative. However, the same animals developed only modest SIV-specific CD8(+) T-cell responses. Nevertheless, high-frequency SIV-specific cellular responses were observed in the rBCG-primed monkeys after boosting with recombinant adenovirus 5 (rAd5) expressing the SIV antigens. These cellular responses were of greater magnitude and more persistent than those generated after vaccination with rAd5 alone. The vaccine-elicited cellular responses were predominantly polyfunctional CD8(+) T cells. These findings support the further exploration of mycobacteria as priming vaccine vectors.
Assuntos
Adenoviridae/genética , Vacina BCG/imunologia , Imunização Secundária/métodos , Macaca mulatta/imunologia , Mycobacterium bovis/imunologia , Vírus da Imunodeficiência Símia/imunologia , Linfócitos T/imunologia , Animais , Vacina BCG/genética , Vacina BCG/metabolismo , Células Cultivadas , Produtos do Gene env/genética , Produtos do Gene env/imunologia , Produtos do Gene env/metabolismo , Produtos do Gene gag/genética , Produtos do Gene gag/imunologia , Produtos do Gene gag/metabolismo , Produtos do Gene pol/genética , Produtos do Gene pol/imunologia , Produtos do Gene pol/metabolismo , Vetores Genéticos/genética , Mycobacterium bovis/genética , Mycobacterium bovis/metabolismo , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/metabolismo , Titulometria , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Vacinas Sintéticas/metabolismoRESUMO
The RV144 Thai trial HIV-1 vaccine of recombinant poxvirus (ALVAC) and recombinant HIV-1 gp120 subtype B/subtype E (B/E) proteins demonstrated 31% vaccine efficacy. Here we design an ALVAC/Pentavalent B/E/E/E/E vaccine to increase the diversity of gp120 motifs in the immunogen to elicit a broader antibody response and enhance protection. We find that immunization of rhesus macaques with the pentavalent vaccine results in protection of 55% of pentavalent-vaccine-immunized macaques from simian-human immunodeficiency virus (SHIV) challenge. Systems serology of the antibody responses identifies plasma antibody binding to HIV-infected cells, peak ADCC antibody titres, NK cell-mediated ADCC and antibody-mediated activation of MIP-1ß in NK cells as the four immunological parameters that best predict decreased infection risk that are improved by the pentavalent vaccine. Thus inclusion of additional gp120 immunogens to a pox-prime/protein boost regimen can augment antibody responses and enhance protection from a SHIV challenge in rhesus macaques.
Assuntos
Vacinas contra a AIDS/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Células Matadoras Naturais/imunologia , Vírus da Imunodeficiência Símia/imunologia , Animais , Proteínas do Sistema Complemento/imunologia , Epitopos/imunologia , Feminino , Anticorpos Anti-HIV/imunologia , HIV-1 , Humanos , Células Matadoras Naturais/citologia , Leucócitos Mononucleares/citologia , Macaca mulatta , Masculino , Mutação , Testes de Neutralização , Fagocitose , Filogenia , Valor Preditivo dos Testes , Ligação Proteica , Proteínas Recombinantes/imunologia , Análise de RegressãoRESUMO
For studies on vaccines and therapies for HIV disease, SIV-HIV chimeric viruses harboring the HIV-1 env gene (SHIVenv) remain the best virus in non-human primate models. However, there are still very few SHIVenv viruses that can cause AIDS in non-CD8-depleted animals. In the present study, a recently created CCR5-using SHIVenv_B3 virus with env gene derived from acute/early HIV-1 infections (AHI) successfully established pathogenic infection in macaques. Through a series of investigations on the evolution, mutational profile, and phenotype of the virus and the resultant humoral immune response in infected rhesus macaques, we found that the E32K mutation in the Env C1 domain was associated with macaque pathogenesis, and that the electrostatic interactions in Env may favor E32K at the gp120 N terminus and "lock" the binding to heptad repeat 1 of gp41 in the trimer and produce a SHIVenv with increased fitness and pathogenesis during macaque infections.
Assuntos
Produtos do Gene env/genética , Infecções por HIV/virologia , HIV-1/genética , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/patogenicidade , Sequência de Aminoácidos , Animais , Anticorpos Antivirais/imunologia , Modelos Animais de Doenças , Evolução Molecular , Produtos do Gene env/química , Produtos do Gene env/imunologia , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/genética , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/genética , Infecções por HIV/imunologia , HIV-1/classificação , HIV-1/imunologia , HIV-1/patogenicidade , Humanos , Imunidade Humoral , Macaca mulatta , Dados de Sequência Molecular , Mutação de Sentido Incorreto , Filogenia , Receptores CCR5/genética , Receptores CCR5/imunologia , Receptores Virais/genética , Receptores Virais/imunologia , Alinhamento de Sequência , Vírus da Imunodeficiência Símia/classificação , Vírus da Imunodeficiência Símia/imunologia , VirulênciaRESUMO
Background. In this study, we analyzed the protective efficacy of a simian immunodeficiency virus (SIV) macaque 239 (SIVmac239) analogue of the clinically tested GOVX-B11 deoxyribonucleic acid (DNA)/modified vaccinia Ankara (MVA) human immunodeficiency virus vaccine. Methods. The tested vaccine used a DNA immunogen mutated to mimic the human vaccine and a regimen with DNA deliveries at weeks 0 and 8 and MVA deliveries at weeks 16 and 32. Twelve weekly rectal challenges with 0.3 animal infectious doses of SIV sootey mangabey E660 (SIVsmE660) were administered starting at 6 months after the last immunization. Results. Over the first 6 rectal exposures to SIVsmE660, <10-year-old tripartite motif-containing protein 5 (TRIM5)α-permissive rhesus macaques showed an 80% reduction in per-exposure risk of infection as opposed to a 46% reduction in animals over 10 years old; and, over the 12 challenges, they showed a 72% as opposed to a 10% reduction. Analyses of elicited immune responses suggested that higher antibody responses in the younger animals had played a role in protection. Conclusions. The simian analogue of the GOVX-B11 HIV provided strong protection against repeated rectal challenges in young adult macaques.
RESUMO
Simian-human immunodeficiency viruses (SHIVs) that mirror natural transmitted/founder (T/F) viruses in man are needed for evaluation of HIV-1 vaccine candidates in nonhuman primates. Currently available SHIVs contain HIV-1 env genes from chronically-infected individuals and do not reflect the characteristics of biologically relevant HIV-1 strains that mediate human transmission. We chose to develop clade C SHIVs, as clade C is the major infecting subtype of HIV-1 in the world. We constructed 10 clade C SHIVs expressing Env proteins from T/F viruses. Three of these ten clade C SHIVs (SHIV KB9 C3, SHIV KB9 C4 and SHIV KB9 C5) replicated in naïve rhesus monkeys. These three SHIVs are mucosally transmissible and are neutralized by sCD4 and several HIV-1 broadly neutralizing antibodies. However, like natural T/F viruses, they exhibit low Env reactivity and a Tier 2 neutralization sensitivity. Of note, none of the clade C T/F SHIVs elicited detectable autologous neutralizing antibodies in the infected monkeys, even though antibodies that neutralized a heterologous Tier 1 HIV-1 were generated. Challenge with these three new clade C SHIVs will provide biologically relevant tests for vaccine protection in rhesus macaques.