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1.
Front Immunol ; 11: 2059, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33013871

RESUMO

The novel, highly contagious coronavirus SARS-CoV-2 spreads rapidly throughout the world, leading to a deadly pandemic of a predominantly respiratory illness called COVID-19. Safe and effective anti-SARS-CoV-2 vaccines are urgently needed. However, emerging immunological observations show hallmarks of significant immunopathological characteristics and dysfunctional immune responses in patients with COVID-19. Combined with existing knowledge about immune responses to other closely related and highly pathogenic coronaviruses, this could forebode significant challenges for vaccine development, including the risk of vaccine failure. Animal data from earlier coronavirus vaccine efforts indicate that elderly people, most at risk from severe COVID-19 disease, could be especially at risk from immunopathologic responses to novel coronavirus vaccines. Bacterial "new old friends" such as Bacille Calmette-Guérin (BCG) or Mycobacterium obuense have the ability to elevate basal systemic levels of type 1 cytokines and immune cells, correlating with increased protection against diverse and unrelated infectious agents, called "trained immunity." Here we describe dysfunctional immune responses induced by coronaviruses, representing potentially difficult to overcome obstacles to safe, effective vaccine development for COVID-19, and outline how trained immunity could help protect high risk populations through immunomodulation with BCG and other "new old friends."


Assuntos
Vacina BCG/imunologia , Betacoronavirus/imunologia , Infecções por Coronavirus/imunologia , Imunidade Celular , Imunidade Inata , Memória Imunológica/imunologia , Pneumonia Viral/imunologia , Vacinação , Idoso , Animais , Vacinas Anticâncer/imunologia , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/virologia , Humanos , Micobactérias não Tuberculosas/imunologia , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Pneumonia Viral/virologia , Risco , Vacinas Virais/efeitos adversos
2.
BMC Infect Dis ; 20(1): 677, 2020 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-32942991

RESUMO

BACKGROUND: Approximately 80% - 90% of individuals infected with latent Mycobacterium tuberculosis (Mtb) remain protected throughout their life-span. The release of unique, latent-phase antigens are known to have a protective role in the immune response against Mtb. Although the BCG vaccine has been administered for nine decades to provide immunity against Mtb, the number of TB cases continues to rise, thereby raising doubts on BCG vaccine efficacy. The shortcomings of BCG have been associated with inadequate processing and presentation of its antigens, an inability to optimally activate T cells against Mtb, and generation of regulatory T cells. Furthermore, BCG vaccination lacks the ability to eliminate latent Mtb infection. With these facts in mind, we selected six immunodominant CD4 and CD8 T cell epitopes of Mtb expressed during latent, acute, and chronic stages of infection and engineered a multi-epitope-based DNA vaccine (C6). RESULT: BALB/c mice vaccinated with the C6 construct along with a BCG vaccine exhibited an expansion of both CD4 and CD8 T cell memory populations and augmented IFN-γ and TNF-α cytokine release. Furthermore, enhancement of dendritic cell and macrophage activation was noted. Consequently, illustrating the elicitation of immunity that helps in the protection against Mtb infection; which was evident by a significant reduction in the Mtb burden in the lungs and spleen of C6 + BCG administered animals. CONCLUSION: Overall, the results suggest that a C6 + BCG vaccination approach may serve as an effective vaccination strategy in future attempts to control TB.


Assuntos
Vacina BCG/imunologia , Epitopos de Linfócito T , Tuberculose/prevenção & controle , Vacinas de DNA/imunologia , Animais , Antígenos de Bactérias/imunologia , Vacina BCG/genética , Vacina BCG/farmacologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Epitopos de Linfócito T/genética , Feminino , Memória Imunológica , Interferon gama/metabolismo , Tuberculose Latente/prevenção & controle , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Mycobacterium tuberculosis/imunologia , Tuberculose/imunologia , Fator de Necrose Tumoral alfa/metabolismo , Vacinas de DNA/farmacologia
3.
PLoS Pathog ; 16(9): e1008887, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32956412

RESUMO

Despite the availability of multiple antibiotics, tuberculosis (TB) remains a major health problem worldwide, with one third of the population latently infected and ~2 million deaths annually. The only available vaccine for TB, Bacillus Calmette Guérin (BCG), is ineffective against adult pulmonary TB. Therefore, alternate strategies that enhance vaccine efficacy are urgently needed. Vaccine efficacy and long-term immune memory are critically dependent on central memory T (TCM) cells, whereas effector memory T (TEM) cells are important for clearing acute infections. Recently, it has been shown that inhibition of the Kv1.3 K+ ion channel, which is predominantly expressed on TEM but not TCM cells, profoundly enhances TCM cell differentiation. We exploited this phenomenon to improve TCM:TEM cell ratios and protective immunity against Mycobacterium tuberculosis infection in response to BCG vaccination of mice. We demonstrate that luteolin, a plant-derived Kv1.3 K+ channel inhibitor, profoundly promotes TCM cells by selectively inhibiting TEM cells, and significantly enhances BCG vaccine efficacy. Thus, addition of luteolin to BCG vaccination may provide a sustainable means to improve vaccine efficacy by boosting host immunity via modulation of memory T cell differentiation.


Assuntos
Vacina BCG/imunologia , Memória Imunológica/efeitos dos fármacos , Canal de Potássio Kv1.3 , Luteolina/farmacologia , Mycobacterium tuberculosis/imunologia , Linfócitos T/imunologia , Tuberculose/imunologia , Animais , Canal de Potássio Kv1.3/antagonistas & inibidores , Canal de Potássio Kv1.3/imunologia , Camundongos , Tuberculose/prevenção & controle
4.
Proc Natl Acad Sci U S A ; 117(39): 24384-24391, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32913053

RESUMO

An improved understanding of human T cell-mediated immunity in COVID-19 is important for optimizing therapeutic and vaccine strategies. Experience with influenza shows that infection primes CD8+ T cell memory to peptides presented by common HLA types like HLA-A2, which enhances recovery and diminishes clinical severity upon reinfection. Stimulating peripheral blood mononuclear cells from COVID-19 convalescent patients with overlapping peptides from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led to the clonal expansion of SARS-CoV-2-specific CD8+ and CD4+ T cells in vitro, with CD4+ T cells being robust. We identified two HLA-A*02:01-restricted SARS-CoV-2-specfic CD8+ T cell epitopes, A2/S269-277 and A2/Orf1ab3183-3191 Using peptide-HLA tetramer enrichment, direct ex vivo assessment of A2/S269 +CD8+ and A2/Orf1ab3183 +CD8+ populations indicated that A2/S269 +CD8+ T cells were detected at comparable frequencies (∼1.3 × 10-5) in acute and convalescent HLA-A*02:01+ patients. These frequencies were higher than those found in uninfected HLA-A*02:01+ donors (∼2.5 × 10-6), but low when compared to frequencies for influenza-specific (A2/M158) and Epstein-Barr virus (EBV)-specific (A2/BMLF1280) (∼1.38 × 10-4) populations. Phenotyping A2/S269 +CD8+ T cells from COVID-19 convalescents ex vivo showed that A2/S269 +CD8+ T cells were predominantly negative for CD38, HLA-DR, PD-1, and CD71 activation markers, although the majority of total CD8+ T cells expressed granzymes and/or perforin. Furthermore, the bias toward naïve, stem cell memory and central memory A2/S269 +CD8+ T cells rather than effector memory populations suggests that SARS-CoV-2 infection may be compromising CD8+ T cell activation. Priming with appropriate vaccines may thus be beneficial for optimizing CD8+ T cell immunity in COVID-19.


Assuntos
Betacoronavirus/imunologia , Linfócitos T CD8-Positivos/imunologia , Infecções por Coronavirus/imunologia , Antígeno HLA-A2/imunologia , Pneumonia Viral/imunologia , Linfócitos T CD4-Positivos/imunologia , Epitopos de Linfócito T , Feminino , Humanos , Memória Imunológica , Imunofenotipagem , Leucócitos Mononucleares/imunologia , Ativação Linfocitária , Masculino , Pessoa de Meia-Idade , Pandemias , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/imunologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia , Proteínas Virais/química , Proteínas Virais/imunologia
5.
Cell ; 183(1): 158-168.e14, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32979941

RESUMO

SARS-CoV-2-specific memory T cells will likely prove critical for long-term immune protection against COVID-19. Here, we systematically mapped the functional and phenotypic landscape of SARS-CoV-2-specific T cell responses in unexposed individuals, exposed family members, and individuals with acute or convalescent COVID-19. Acute-phase SARS-CoV-2-specific T cells displayed a highly activated cytotoxic phenotype that correlated with various clinical markers of disease severity, whereas convalescent-phase SARS-CoV-2-specific T cells were polyfunctional and displayed a stem-like memory phenotype. Importantly, SARS-CoV-2-specific T cells were detectable in antibody-seronegative exposed family members and convalescent individuals with a history of asymptomatic and mild COVID-19. Our collective dataset shows that SARS-CoV-2 elicits broadly directed and functionally replete memory T cell responses, suggesting that natural exposure or infection may prevent recurrent episodes of severe COVID-19.


Assuntos
Convalescença , Infecções por Coronavirus/imunologia , Pneumonia Viral/imunologia , Linfócitos T/imunologia , Adulto , Anticorpos Antivirais/imunologia , Infecções Assintomáticas , Betacoronavirus/imunologia , Infecções por Coronavirus/patologia , Feminino , Humanos , Memória Imunológica , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/patologia
7.
Eur J Immunol ; 50(9): 1283-1294, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32910469

RESUMO

Studies on the interactions between SARS-CoV-2 and humoral immunity are fundamental to elaborate effective therapies including vaccines. We used polychromatic flow cytometry, coupled with unsupervised data analysis and principal component analysis (PCA), to interrogate B cells in untreated patients with COVID-19 pneumonia. COVID-19 patients displayed normal plasma levels of the main immunoglobulin classes, of antibodies against common antigens or against antigens present in common vaccines. However, we found a decreased number of total and naïve B cells, along with decreased percentages and numbers of memory switched and unswitched B cells. On the contrary, IgM+ and IgM- plasmablasts were significantly increased. In vitro cell activation revealed that B lymphocytes showed a normal proliferation index and number of dividing cells per cycle. PCA indicated that B-cell number, naive and memory B cells but not plasmablasts clustered with patients who were discharged, while plasma IgM level, C-reactive protein, D-dimer, and SOFA score with those who died. In patients with pneumonia, the derangement of the B-cell compartment could be one of the causes of the immunological failure to control SARS-Cov2, have a relevant influence on several pathways, organs and systems, and must be considered to develop vaccine strategies.


Assuntos
Anticorpos Antivirais/sangue , Linfócitos B/imunologia , Betacoronavirus/patogenicidade , Infecções por Coronavirus/imunologia , Isotipos de Imunoglobulinas/sangue , Pulmão/imunologia , Pneumonia Viral/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antivirais/classificação , Linfócitos B/virologia , Betacoronavirus/imunologia , Proteína C-Reativa/imunologia , Estudos de Casos e Controles , Proliferação de Células , Infecções por Coronavirus/mortalidade , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Estudos Transversais , Citocinas/genética , Citocinas/imunologia , Feminino , Produtos de Degradação da Fibrina e do Fibrinogênio/imunologia , Humanos , Imunidade Humoral , Memória Imunológica , Pulmão/patologia , Pulmão/virologia , Ativação Linfocitária , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Escores de Disfunção Orgânica , Pandemias , Pneumonia Viral/mortalidade , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Cultura Primária de Células , Índice de Gravidade de Doença , Análise de Sobrevida
8.
Nat Commun ; 11(1): 4475, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32901029

RESUMO

Tissue resident memory CD8+ T cells (Trm) are poised for immediate reactivation at sites of pathogen entry and provide optimal protection of mucosal surfaces. The intestinal tract represents a portal of entry for many infectious agents; however, to date specific strategies to enhance Trm responses at this site are lacking. Here, we present TMDI (Transient Microbiota Depletion-boosted Immunization), an approach that leverages antibiotic treatment to temporarily restrain microbiota-mediated colonization resistance, and favor intestinal expansion to high densities of an orally-delivered Listeria monocytogenes strain carrying an antigen of choice. By augmenting the local chemotactic gradient as well as the antigenic load, this procedure generates a highly expanded pool of functional, antigen-specific intestinal Trm, ultimately enhancing protection against infectious re-challenge in mice. We propose that TMDI is a useful model to dissect the requirements for optimal Trm responses in the intestine, and also a potential platform to devise novel mucosal vaccination approaches.


Assuntos
Microbioma Gastrointestinal/imunologia , Imunidade nas Mucosas , Administração Oral , Animais , Antígenos/administração & dosagem , Linfócitos T CD8-Positivos/imunologia , Quimiotaxia/imunologia , Feminino , Microbioma Gastrointestinal/efeitos dos fármacos , Interações entre Hospedeiro e Microrganismos/imunologia , Imunidade nas Mucosas/efeitos dos fármacos , Memória Imunológica , Listeria monocytogenes/crescimento & desenvolvimento , Listeria monocytogenes/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ovalbumina/administração & dosagem , Estreptomicina/administração & dosagem
10.
Nat Commun ; 11(1): 4767, 2020 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-32958743

RESUMO

Psoriatic arthritis (PsA) is a debilitating immune-mediated inflammatory arthritis of unknown pathogenesis commonly affecting patients with skin psoriasis. Here we use complementary single-cell approaches to study leukocytes from PsA joints. Mass cytometry demonstrates a 3-fold expansion of memory CD8 T cells in the joints of PsA patients compared to peripheral blood. Meanwhile, droplet-based and plate-based single-cell RNA sequencing of paired T cell receptor alpha and beta chain sequences show pronounced CD8 T cell clonal expansions within the joints. Transcriptome analyses find these expanded synovial CD8 T cells to express cycling, activation, tissue-homing and tissue residency markers. T cell receptor sequence comparison between patients identifies clonal convergence. Finally, chemokine receptor CXCR3 is upregulated in the expanded synovial CD8 T cells, while two CXCR3 ligands, CXCL9 and CXCL10, are elevated in PsA synovial fluid. Our data thus provide a quantitative molecular insight into the cellular immune landscape of psoriatic arthritis.


Assuntos
Artrite Psoriásica/imunologia , Linfócitos T CD8-Positivos/imunologia , Seleção Clonal Mediada por Antígeno , Receptores de Retorno de Linfócitos/metabolismo , Líquido Sinovial/imunologia , Artrite Psoriásica/sangue , Linfócitos T CD8-Positivos/metabolismo , Perfilação da Expressão Gênica , Humanos , Memória Imunológica , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Receptores de Quimiocinas/metabolismo , Receptores de Retorno de Linfócitos/genética , Análise de Célula Única , Membrana Sinovial/imunologia
11.
mBio ; 11(5)2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32978311

RESUMO

The high susceptibility of humans to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the cause of coronavirus disease 2019 (COVID-19), reflects the novelty of the virus and limited preexisting B cell immunity. IgG against the SARS-CoV-2 spike (S) protein, which carries the novel receptor binding domain (RBD), is absent or at low levels in unexposed individuals. To better understand the B cell response to SARS-CoV-2 infection, we asked whether virus-reactive memory B cells (MBCs) were present in unexposed subjects and whether MBC generation accompanied virus-specific IgG production in infected subjects. We analyzed sera and peripheral blood mononuclear cells (PBMCs) from non-SARS-CoV-2-exposed healthy donors and COVID-19 convalescent subjects. Serum IgG levels specific for SARS-CoV-2 proteins (S, including the RBD and S2 subunit, and nucleocapsid [N]) and non-SARS-CoV-2 proteins were related to measurements of circulating IgG MBC levels. Anti-RBD IgG was absent in unexposed subjects. Most unexposed subjects had anti-S2 IgG, and a minority had anti-N IgG, but IgG MBCs with these specificities were not detected, perhaps reflecting low frequencies. Convalescent subjects had high levels of IgG against the RBD, S2, and N, together with large populations of RBD- and S2-reactive IgG MBCs. Notably, IgG titers against the S protein of the human coronavirus OC43 were higher in convalescent subjects than in unexposed subjects and correlated strongly with anti-S2 titers. Our findings indicate cross-reactive B cell responses against the S2 subunit that might enhance broad coronavirus protection. Importantly, our demonstration of MBC induction by SARS-CoV-2 infection suggests that a durable form of B cell immunity is maintained even if circulating antibody levels wane.IMPORTANCE The recent rapid worldwide spread of SARS-CoV-2 has established a pandemic of potentially serious disease in the highly susceptible human population. Key issues are whether humans have preexisting immune memory that provides some protection against SARS-CoV-2 and whether SARS-CoV-2 infection generates lasting immune protection against reinfection. Our analysis focused on pre- and postinfection IgG and IgG memory B cells (MBCs) reactive to SARS-CoV-2 proteins. Most importantly, we demonstrate that infection generates both IgG and IgG MBCs against the novel receptor binding domain and the conserved S2 subunit of the SARS-CoV-2 spike protein. Thus, even if antibody levels wane, long-lived MBCs remain to mediate rapid antibody production. Our study results also suggest that SARS-CoV-2 infection strengthens preexisting broad coronavirus protection through S2-reactive antibody and MBC formation.


Assuntos
Linfócitos B/imunologia , Betacoronavirus/imunologia , Infecções por Coronavirus/imunologia , Imunoglobulina G/imunologia , Pneumonia Viral/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Adulto , Anticorpos Antivirais/imunologia , Linfócitos B/virologia , Convalescença , Reações Cruzadas , Feminino , Voluntários Saudáveis , Humanos , Memória Imunológica , Masculino , Pessoa de Meia-Idade , Proteínas do Nucleocapsídeo/imunologia , Pandemias , Domínios e Motivos de Interação entre Proteínas , Subunidades Proteicas , Glicoproteína da Espícula de Coronavírus/química
14.
PLoS Pathog ; 16(8): e1008714, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32750095

RESUMO

Seasonal influenza virus infections cause 290,000-650,000 deaths annually and severe morbidity in 3-5 million people. CD8+ T-cell responses towards virus-derived peptide/human leukocyte antigen (HLA) complexes provide the broadest cross-reactive immunity against human influenza viruses. Several universally-conserved CD8+ T-cell specificities that elicit prominent responses against human influenza A viruses (IAVs) have been identified. These include HLA-A*02:01-M158-66 (A2/M158), HLA-A*03:01-NP265-273, HLA-B*08:01-NP225-233, HLA-B*18:01-NP219-226, HLA-B*27:05-NP383-391 and HLA-B*57:01-NP199-207. The immunodominance hierarchies across these universal CD8+ T-cell epitopes were however unknown. Here, we probed immunodominance status of influenza-specific universal CD8+ T-cells in HLA-I heterozygote individuals expressing two or more universal HLAs for IAV. We found that while CD8+ T-cell responses directed towards A2/M158 were generally immunodominant, A2/M158+CD8+ T-cells were markedly diminished (subdominant) in HLA-A*02:01/B*27:05-expressing donors following ex vivo and in vitro analyses. A2/M158+CD8+ T-cells in non-HLA-B*27:05 individuals were immunodominant, contained optimal public TRBV19/TRAV27 TCRαß clonotypes and displayed highly polyfunctional and proliferative capacity, while A2/M158+CD8+ T cells in HLA-B*27:05-expressing donors were subdominant, with largely distinct TCRαß clonotypes and consequently markedly reduced avidity, proliferative and polyfunctional efficacy. Our data illustrate altered immunodominance patterns and immunodomination within human influenza-specific CD8+ T-cells. Accordingly, our work highlights the importance of understanding immunodominance hierarchies within individual donors across a spectrum of prominent virus-specific CD8+ T-cell specificities prior to designing T cell-directed vaccines and immunotherapies, for influenza and other infectious diseases.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Antígeno HLA-B27/genética , Epitopos Imunodominantes/imunologia , Influenza Humana/imunologia , Adulto , Idoso , Epitopos de Linfócito T/imunologia , Feminino , Antígeno HLA-B27/imunologia , Humanos , Epitopos Imunodominantes/genética , Memória Imunológica , Vírus da Influenza A/fisiologia , Influenza Humana/genética , Influenza Humana/virologia , Masculino , Pessoa de Meia-Idade , Adulto Jovem
15.
Front Immunol ; 11: 1782, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760409

RESUMO

As the SARS-CoV-2 virus wreaks havoc on the populations, health care infrastructures and economies of nations around the world, finding ways to protect health care workers and bolster immune responses in the general population while we await an effective vaccine will be the difference between life and death for many people. Recent studies show that innate immune populations may possess a form of memory, termed Trained Immunity (TRIM), where innate immune cells undergo metabolic, mitochondrial, and epigenetic reprogramming following exposure to an initial stimulus that results in a memory phenotype of enhanced immune responses when exposed to a secondary, heterologous, stimulus. Throughout the literature, it has been shown that the induction of TRIM using such inducers as the BCG vaccine and ß-glucan can provide protection through altered immune responses against a range of viral infections. Here we hypothesize a potential role for ß-glucan in decreasing worldwide morbidity and mortality due to COVID-19, and posit several ideas as to how TRIM may actually shape the observed epidemiological phenomena related to COVID-19. We also evaluate the potential effects of ß-glucan in relation to the immune dysregulation and cytokine storm observed in COVID-19. Ultimately, we hypothesize that the use of oral ß-glucan in a prophylactic setting could be an effective way to boost immune responses and abrogate symptoms in COVID-19, though clinical trials are necessary to confirm the efficacy of this treatment and to further examine differential effects of ß-glucan's from various sources.


Assuntos
Antivirais/uso terapêutico , Betacoronavirus , Infecções por Coronavirus/dietoterapia , Infecções por Coronavirus/imunologia , Fibras na Dieta/uso terapêutico , Memória Imunológica/efeitos dos fármacos , Pneumonia Viral/dietoterapia , Pneumonia Viral/imunologia , beta-Glucanas/uso terapêutico , Administração Oral , Adulto , Fatores Etários , Animais , Antivirais/administração & dosagem , Antivirais/imunologia , Antivirais/farmacologia , Vacina BCG/imunologia , Criança , Infecções por Coronavirus/sangue , Infecções por Coronavirus/virologia , Citocinas/sangue , Fibras na Dieta/administração & dosagem , Epigênese Genética/imunologia , Humanos , Imunidade Inata/efeitos dos fármacos , Pandemias , Pneumonia Viral/sangue , Pneumonia Viral/virologia , Profilaxia Pré-Exposição , beta-Glucanas/administração & dosagem , beta-Glucanas/imunologia , beta-Glucanas/farmacologia
16.
J Exp Med ; 217(12)2020 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-32820330

RESUMO

Type I interferons (IFN-I) are a major antiviral defense and are critical for the activation of the adaptive immune system. However, early viral clearance by IFN-I could limit antigen availability, which could in turn impinge upon the priming of the adaptive immune system. In this study, we hypothesized that transient IFN-I blockade could increase antigen presentation after acute viral infection. To test this hypothesis, we infected mice with viruses coadministered with a single dose of IFN-I receptor-blocking antibody to induce a short-term blockade of the IFN-I pathway. This resulted in a transient "spike" in antigen levels, followed by rapid antigen clearance. Interestingly, short-term IFN-I blockade after coronavirus, flavivirus, rhabdovirus, or arenavirus infection induced a long-lasting enhancement of immunological memory that conferred improved protection upon subsequent reinfections. Short-term IFN-I blockade also improved the efficacy of viral vaccines. These findings demonstrate a novel mechanism by which IFN-I regulate immunological memory and provide insights for rational vaccine design.


Assuntos
Imunogenicidade da Vacina/imunologia , Interferon Tipo I/antagonistas & inibidores , Interferon-alfa/imunologia , Receptor de Interferon alfa e beta/imunologia , Vacinas Virais/imunologia , Infecção por Zika virus/imunologia , Zika virus/imunologia , Animais , Anticorpos Bloqueadores/imunologia , Anticorpos Bloqueadores/farmacologia , Anticorpos Antivirais/imunologia , Apresentação do Antígeno/imunologia , Linfócitos T CD8-Positivos/metabolismo , Células Dendríticas/imunologia , Modelos Animais de Doenças , Expressão Gênica/imunologia , Células HEK293 , Humanos , Memória Imunológica , Interferon-alfa/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptor de Interferon alfa e beta/genética , Transfecção , Infecção por Zika virus/virologia
17.
Cell Immunol ; 356: 104187, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32745670

RESUMO

Mycobacterium bovis BCG, a live attenuated tuberculosis vaccine offers protection against disseminated TB in children. BCG exhibits heterologous protective effects against unrelated infections and reduces infant mortality due to non-mycobacterial infections. Recent reports have suggested that BCG vaccination might have protective effects against COVID-19, however it is highly unlikely that BCG vaccine in its current form can offer complete protection against SARS-CoV-2 infection due to the lack of specific immunity. Nonetheless, recombinant BCG strains expressing antigens of SARS-CoV-2 may offer protection against COVID-19 due to the activation of innate as well as specific adaptive immune response. Further proven safety records of BCG in humans, its adjuvant activity and low cost manufacturing makes it a frontrunner in the vaccine development to stop this pandemic. In this review we discuss about the heterologous effects of BCG, induction of trained immunity and its implication in development of a potential vaccine against COVID-19 pandemic.


Assuntos
Vacina BCG/uso terapêutico , Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Betacoronavirus , Humanos , Imunidade Inata , Memória Imunológica , Vacinas Atenuadas/uso terapêutico
18.
Nature ; 584(7820): 274-278, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32760003

RESUMO

Colonization by the microbiota causes a marked stimulation of B cells and induction of immunoglobulin, but mammals colonized with many taxa have highly complex and individualized immunoglobulin repertoires1,2. Here we use a simplified model of defined transient exposures to different microbial taxa in germ-free mice3 to deconstruct how the microbiota shapes the B cell pool and its functional responsiveness. We followed the development of the immunoglobulin repertoire in B cell populations, as well as single cells by deep sequencing. Microbial exposures at the intestinal mucosa generated oligoclonal responses that differed from those of germ-free mice, and from the diverse repertoire that was generated after intravenous systemic exposure to microbiota. The IgA repertoire-predominantly to cell-surface antigens-did not expand after dose escalation, whereas increased systemic exposure broadened the IgG repertoire to both microbial cytoplasmic and cell-surface antigens. These microbial exposures induced characteristic immunoglobulin heavy-chain repertoires in B cells, mainly at memory and plasma cell stages. Whereas sequential systemic exposure to different microbial taxa diversified the IgG repertoire and facilitated alternative specific responses, sequential mucosal exposure produced limited overlapping repertoires and the attrition of initial IgA binding specificities. This shows a contrast between a flexible response to systemic exposure with the need to avoid fatal sepsis, and a restricted response to mucosal exposure that reflects the generic nature of host-microbial mutualism in the mucosa.


Assuntos
Linfócitos B/citologia , Linfócitos B/imunologia , Imunidade nas Mucosas/imunologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Simbiose/imunologia , Administração Intravenosa , Administração Oral , Animais , Clostridiales/imunologia , Clostridiales/isolamento & purificação , Escherichia coli/imunologia , Escherichia coli/isolamento & purificação , Feminino , Vida Livre de Germes , Imunoglobulina A/química , Imunoglobulina A/imunologia , Imunoglobulina G/química , Imunoglobulina G/imunologia , Cadeias Pesadas de Imunoglobulinas/imunologia , Memória Imunológica/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Plasmócitos/citologia , Plasmócitos/imunologia , Priming de Repetição
20.
Nat Med ; 26(10): 1623-1635, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32807934

RESUMO

Improved understanding and management of COVID-19, a potentially life-threatening disease, could greatly reduce the threat posed by its etiologic agent, SARS-CoV-2. Toward this end, we have identified a core peripheral blood immune signature across 63 hospital-treated patients with COVID-19 who were otherwise highly heterogeneous. The signature includes discrete changes in B and myelomonocytic cell composition, profoundly altered T cell phenotypes, selective cytokine/chemokine upregulation and SARS-CoV-2-specific antibodies. Some signature traits identify links with other settings of immunoprotection and immunopathology; others, including basophil and plasmacytoid dendritic cell depletion, correlate strongly with disease severity; while a third set of traits, including a triad of IP-10, interleukin-10 and interleukin-6, anticipate subsequent clinical progression. Hence, contingent upon independent validation in other COVID-19 cohorts, individual traits within this signature may collectively and individually guide treatment options; offer insights into COVID-19 pathogenesis; and aid early, risk-based patient stratification that is particularly beneficial in phasic diseases such as COVID-19.


Assuntos
Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Infecções por Coronavirus/imunologia , Citocinas/imunologia , Células Dendríticas/imunologia , Pneumonia Viral/imunologia , Linfócitos T/imunologia , Idoso , Subpopulações de Linfócitos B/imunologia , Basófilos/imunologia , Betacoronavirus , Estudos de Casos e Controles , Ciclo Celular , Quimiocina CXCL10/imunologia , Quimiocinas/imunologia , Estudos de Coortes , Infecções por Coronavirus/sangue , Progressão da Doença , Feminino , Citometria de Fluxo , Hospitalização , Humanos , Memória Imunológica , Imunofenotipagem , Interleucina-10/imunologia , Interleucina-6/imunologia , Contagem de Leucócitos , Ativação Linfocitária/imunologia , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/sangue , Prognóstico , Índice de Gravidade de Doença , Subpopulações de Linfócitos T/imunologia , Regulação para Cima
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