RESUMO
Prior immunological exposure to dengue virus can be both protective and disease-enhancing during subsequent infections with different dengue virus serotypes. We provide here a systematic, longitudinal analysis of B cell, T cell, and antibody responses in the same patients. Antibody responses as well as T and B cell activation differentiate primary from secondary responses. Hospitalization is associated with lower frequencies of activated, terminally differentiated T cells and higher percentages of effector memory CD4 T cells. Patients with more severe disease tend to have higher percentages of plasmablasts. This does not translate into long-term antibody titers, since neutralizing titers after 6 months correlate with percentages of specific memory B cells, but not with acute plasmablast activation. Overall, our unbiased analysis reveals associations between cellular profiles and disease severity, opening opportunities to study immunopathology in dengue disease and the potential predictive value of these parameters.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Fenótipo , Tempo , Anticorpos Neutralizantes/genética , Anticorpos Antivirais/genética , Reações Cruzadas/imunologia , Dengue/imunologia , Vírus da Dengue/genética , Vírus da Dengue/imunologia , Humanos , Plasmócitos/imunologia , SorogrupoRESUMO
Clinically important broadly reactive B cells evolve during multiple infections, with B cells re-activated after secondary infection differing from B cells activated after a primary infection. Here we studied CD27highCD38high plasmablasts from patients with a primary or secondary dengue virus infection. Three transcriptionally and functionally distinct clusters were identified. The largest cluster 0/1 was plasma cell-related, with cells coding for serotype cross-reactive antibodies of the IgG1 isotype, consistent with memory B cell activation during an extrafollicular response. Cells in clusters 2 and 3 expressed low levels of antibody genes and high levels of genes associated with oxidative phosphorylation, EIF2 pathway, and mitochondrial dysfunction. Clusters 2 and 3 showed a transcriptional footprint of T cell help, in line with activation from naive B cells or memory B cells. Our results contribute to the understanding of the parallel B cell activation events that occur in humans after natural primary and secondary infection.
RESUMO
Influenza is a leading cause of death in the elderly, and the vaccine protects only a fraction of this population. A key aspect of antibody-mediated anti-influenza virus immunity is adaptation to antigenically distinct epitopes on emerging strains. We examined factors contributing to reduced influenza vaccine efficacy in the elderly and uncovered a dramatic reduction in the accumulation of de novo immunoglobulin gene somatic mutations upon vaccination. This reduction is associated with a significant decrease in the capacity of antibodies to target the viral glycoprotein, hemagglutinin (HA), and critical protective epitopes surrounding the HA receptor-binding domain. Immune escape by antigenic drift, in which viruses generate mutations in key antigenic epitopes, becomes highly exaggerated. Because of this reduced adaptability, most B cells activated in the elderly cohort target highly conserved but less potent epitopes. Given these findings, vaccines driving immunoglobulin gene somatic hypermutation should be a priority to protect elderly individuals.
Assuntos
Linfócitos B/imunologia , Epitopos/imunologia , Imunidade Humoral , Vacinas contra Influenza/imunologia , Orthomyxoviridae/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Epitopos/genética , Voluntários Saudáveis , Humanos , Vacinas contra Influenza/administração & dosagem , Pessoa de Meia-Idade , Mutação , Orthomyxoviridae/genética , Adulto JovemRESUMO
Generating a broadly protective influenza vaccine is critical to global health. Understanding how immune memory influences influenza immunity is central to this goal. We undertook an in-depth study of the B cell response to the pandemic 2009 H1N1 vaccine over consecutive years. Analysis of monoclonal antibodies generated from vaccine-induced plasmablasts demonstrated that individuals with low preexisting serological titers to the vaccinating strain generated a broadly reactive, hemagglutinin (HA) stalk-biased response. Higher preexisting serum antibody levels correlated with a strain-specific HA head-dominated response. We demonstrate that this HA head immunodominance encompasses poor accessibility of the HA stalk epitopes. Further, we show polyreactivity of HA stalk-reactive antibodies that could cause counterselection of these cells. Thus, preexisting memory B cells against HA head epitopes predominate, inhibiting a broadly protective response against the HA stalk upon revaccination with similar strains. Consideration of influenza exposure history is critical for new vaccine strategies designed to elicit broadly neutralizing antibodies.
Assuntos
Linfócitos B/virologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/virologia , Adulto , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Separação Celular , Cães , Epitopos/imunologia , Feminino , Humanos , Vírus da Influenza A Subtipo H1N1 , Leucócitos Mononucleares/citologia , Células Madin Darby de Rim Canino , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Filogenia , Ressonância de Plasmônio de SuperfícieRESUMO
Breakdown of B cell tolerance is a cardinal feature of systemic lupus erythematosus (SLE). Increased numbers of autoreactive mature naïve B cells have been described in SLE patients and autoantibodies have been shown to arise from autoreactive and non-autoreactive precursors. How these defects, in the regulation of B cell tolerance and selection, influence germinal center (GC) reactions that are directed towards foreign antigens has yet to be investigated. Here, we examined the characteristics of post-GC foreign antigen-specific B cells from SLE patients and healthy controls by analyzing monoclonal antibodies generated from plasmablasts induced specifically by influenza vaccination. We report that many of the SLE patients had anti-influenza antibodies with higher binding affinity and neutralization capacity than those from controls. Although overall frequencies of autoreactivity in the influenza-specific plasmablasts were similar for SLE patients and controls, the variable gene repertoire of influenza-specific plasmablasts from SLE patients was altered, with increased usage of JH6 and long heavy chain CDR3 segments. We found that high affinity anti-influenza antibodies generally characterize the plasmablast responses of SLE patients with low levels of autoreactivity; however, certain exceptions were noted. The high-avidity antibody responses in SLE patients may also be correlated with cytokines that are abnormally expressed in lupus. These findings provide insights into the effects of dysregulated immunity on the quality of antibody responses following influenza vaccination and further our understanding of the underlying abnormalities of lupus.
Assuntos
Anticorpos Monoclonais/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Orthomyxoviridae/imunologia , Afinidade de Anticorpos , Formação de Anticorpos , Estudos de Casos e Controles , Humanos , Vacinas contra Influenza/administração & dosagemRESUMO
The emergence and seasonal persistence of pathogenic H7N9 influenza viruses in China have raised concerns about the pandemic potential of this strain, which, if realized, would have a substantial effect on global health and economies. H7N9 viruses are able to bind to human sialic acid receptors and are also able to develop resistance to neuraminidase inhibitors without a loss in fitness. It is not clear whether prior exposure to circulating human influenza viruses or influenza vaccination confers immunity to H7N9 strains. Here, we demonstrate that 3 of 83 H3 HA-reactive monoclonal antibodies generated by individuals that had previously undergone influenza A virus vaccination were able to neutralize H7N9 viruses and protect mice against homologous challenge. The H7N9-neutralizing antibodies bound to the HA stalk domain but exhibited a difference in their breadth of reactivity to different H7 influenza subtypes. Mapping viral escape mutations suggested that these antibodies bind at least two different epitopes on the stalk region. Together, these results indicate that these broadly neutralizing antibodies may contribute to the development of therapies against H7N9 strains and may also be effective against pathogenic H7 strains that emerge in the future.
Assuntos
Anticorpos Neutralizantes/fisiologia , Anticorpos Antivirais/fisiologia , Subtipo H7N9 do Vírus da Influenza A/imunologia , Influenza Humana/prevenção & controle , Vacinação , Animais , Anticorpos Monoclonais/fisiologia , Reações Cruzadas , Cães , Feminino , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Vírus da Influenza A Subtipo H3N2/imunologia , Subtipo H7N9 do Vírus da Influenza A/genética , Vacinas contra Influenza , Influenza Humana/imunologia , Influenza Humana/virologia , Células Madin Darby de Rim Canino , Camundongos Endogâmicos BALB C , Testes de Neutralização , Mutação PuntualRESUMO
UNLABELLED: Reactivation of memory B cells allows for a rapid and robust immune response upon challenge with the same antigen. Variant influenza virus strains generated through antigenic shift or drift are encountered multiple times over the lifetime of an individual. One might predict, then, that upon vaccination with the trivalent influenza vaccine across multiple years, the antibody response would become more and more dominant toward strains consistently present in the vaccine at the expense of more divergent strains. However, when we analyzed the vaccine-induced plasmablast, memory, and serological responses to the trivalent influenza vaccine between 2006 and 2013, we found that the B cell response was most robust against more divergent strains. Overall, the antibody response was highest when one or more strains contained in the vaccine varied from year to year. This suggests that in the broader immunological context of viral antigen exposure, the B cell response to variant influenza virus strains is not dictated by the composition of the memory B cell precursor pool. The outcome is instead a diversified B cell response. IMPORTANCE: Vaccine strategies are being designed to boost broadly reactive B cells present in the memory repertoire to provide universal protection to the influenza virus. It is important to understand how past exposure to influenza virus strains affects the response to subsequent immunizations. The viral epitopes targeted by B cells responding to the vaccine may be a direct reflection of the B cell memory specificities abundant in the preexisting immune repertoire, or other factors may influence the vaccine response. Here, we demonstrate that high preexisting serological antibody levels to a given influenza virus strain correlate with low production of antibody-secreting cells and memory B cells recognizing that strain upon revaccination. In contrast, introduction of antigenically novel strains generates a robust B cell response. Thus, both the preexisting memory B cell repertoire and serological antibody levels must be taken into consideration in predicting the quality of the B cell response to new prime-boost vaccine strategies.
Assuntos
Anticorpos Antivirais/sangue , Formação de Anticorpos , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Orthomyxoviridae/imunologia , Adulto , Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Feminino , Humanos , Vacinas contra Influenza/administração & dosagem , Influenza Humana/sangue , Influenza Humana/virologia , Masculino , Pessoa de Meia-Idade , Orthomyxoviridae/fisiologia , Vacinação , Adulto JovemRESUMO
Staphylococcus aureus bacterial infection commonly results in chronic or recurrent disease, suggesting that humoral memory responses are hampered. Understanding how S. aureus subverts the immune response is critical for the rescue of host natural humoral immunity and vaccine development. S. aureus expresses the virulence factor Protein A (SpA) on all clinical isolates, and SpA has been shown in mice to expand and ablate variable heavy 3 (VH3) idiotype B cells. The effects of SpA during natural infection, however, have not been addressed. Acutely activated B cells, or plasmablasts (PBs), were analyzed to dissect the ongoing immune response to infection through the production of monoclonal antibodies (mAbs). The B cells that were activated by infection had a highly limited response. When screened against multiple S. aureus antigens, only high-affinity binding to SpA was observed. Consistently, PBs underwent affinity maturation, but their B cell receptors demonstrated significant bias toward the VH3 idiotype. These data suggest that the superantigenic activity of SpA leads to immunodominance, limiting host responses to other S. aureus virulence factors that would be necessary for protection and memory formation.
Assuntos
Evasão da Resposta Imune/imunologia , Infecções Estafilocócicas/imunologia , Proteína Estafilocócica A/imunologia , Staphylococcus aureus/imunologia , Adulto , Idoso , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Linfócitos B/imunologia , Linfócitos B/metabolismo , Citometria de Fluxo , Centro Germinativo/imunologia , Centro Germinativo/metabolismo , Células HEK293 , Interações Hospedeiro-Patógeno/imunologia , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Pesadas de Imunoglobulinas/imunologia , Região Variável de Imunoglobulina/genética , Região Variável de Imunoglobulina/imunologia , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Plasmócitos/imunologia , Plasmócitos/metabolismo , Células Precursoras de Linfócitos B/imunologia , Células Precursoras de Linfócitos B/metabolismo , Análise de Sequência de DNA , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/metabolismo , Staphylococcus aureus/fisiologia , Fatores de Virulência/imunologia , Adulto JovemRESUMO
We characterized human monoclonal antibodies (MAbs) cloned from influenza virus-infected patients and from influenza vaccine recipients by complement-dependent lysis (CDL) assay. Most MAbs active in CDL were neutralizing, but not all neutralizing MAbs can mediate CDL. Two of the three stalk-specific neutralizing MAbs tested were able to mediate CDL and were more cross-reactive to temporally distant H1N1 strains than the conventional hemagglutination-inhibiting and neutralizing MAbs. One of the stalk-specific MAbs was subtype cross-reactive to H1 and H2 hemagglutinins, suggesting a role for stalk-specific antibodies in protection against influenza illness, especially by a novel viral subtype which can cause pandemics.
Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Proteínas do Sistema Complemento/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Anticorpos Monoclonais/isolamento & purificação , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/isolamento & purificação , Anticorpos Antivirais/isolamento & purificação , Morte Celular , Reações Cruzadas , Humanos , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Dados de Sequência Molecular , Análise de Sequência de DNARESUMO
Since its first administration in the 1940s, the influenza vaccine has provided tremendous relief against influenza infections. However, time has revealed the ultimate limit of the vaccine and the call for its reinvention has now come, just as we are beginning to appreciate the antibody immune responses vital in preventing infections. New strategies to design the influenza vaccine rely on selectively inducing broadly neutralizing antibodies that are specific for highly conserved viral epitopes. Such approaches take us away from the limited range of protection provided by current seasonal influenza vaccines and towards a future with a pan-influenza vaccine capable of providing universal strain coverage.
Assuntos
Linfócitos B/imunologia , Vacinas contra Influenza/imunologia , Animais , Humanos , Imunidade Humoral , Vírus da Influenza A/imunologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controleRESUMO
Monoclonal antibody technology has undergone rapid and innovative reinvention over the last 30 years. Application of these technologies to human samples revealed valuable therapeutic and experimental insights. These technologies, each with their own benefits and flaws, have proven indispensable for immunological research and in our fight to provide new treatments and improved vaccines for infectious disease.
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The 2009 pandemic H1N1 influenza pandemic demonstrated the global health threat of reassortant influenza strains. Herein, we report a detailed analysis of plasmablast and monoclonal antibody responses induced by pandemic H1N1 infection in humans. Unlike antibodies elicited by annual influenza vaccinations, most neutralizing antibodies induced by pandemic H1N1 infection were broadly cross-reactive against epitopes in the hemagglutinin (HA) stalk and head domain of multiple influenza strains. The antibodies were from cells that had undergone extensive affinity maturation. Based on these observations, we postulate that the plasmablasts producing these broadly neutralizing antibodies were predominantly derived from activated memory B cells specific for epitopes conserved in several influenza strains. Consequently, most neutralizing antibodies were broadly reactive against divergent H1N1 and H5N1 influenza strains. This suggests that a pan-influenza vaccine may be possible, given the right immunogen. Antibodies generated potently protected and rescued mice from lethal challenge with pandemic H1N1 or antigenically distinct influenza strains, making them excellent therapeutic candidates.
Assuntos
Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Influenza Humana/imunologia , Adulto , Animais , Reações Cruzadas , Epitopos de Linfócito B/imunologia , Feminino , Humanos , Memória Imunológica , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Adulto JovemRESUMO
Virus-specific CD8 T cells are activated when their T-cell receptors (TCRs) recognize the specific viral peptide/major histocompatibility complex (MHC) class I (pMHC) complexes present on the surface of infected cells. Antibodies able to recognize the specific pMHC can mimic TCR specificity and both represent a valuable biological tool to visualize pMHC complexes on infected cells and serve as a delivery system for highly targeted therapies. To evaluate these possibilities, we created a monoclonal antibody able to specifically recognize a hepatitis B virus (HBV) envelope epitope (Env at positions 183 to 91 [Env183-91]) presented by the HLA-A201 molecule, and we tested its ability to recognize HBV-infected hepatocytes and to deliver a cargo to a specific target. We demonstrate that this antibody detects and visualizes the processed product of HBV proteins produced in naturally HBV-infected cells, is not inhibited by soluble HBV proteins present in patient sera, and mediates the intracellular delivery of a fluorescent molecule to target cells. Additionally, compared to CD8 T cells specific for the same HBV epitope, the TCR-like antibody has both a superior sensitivity and a specificity focused on distinct amino acids within the epitope. These data demonstrate that a T-cell receptor-like antibody can be used to determine the quantitative relationship between HBV replication and specific antigen presentation to CD8 T cells and serves as a novel therapeutic delivery platform for personalized health care for HBV-infected patients.