RESUMO
Vitiligo is an autoimmune disease of the skin that targets pigment-producing melanocytes and results in patches of depigmentation that are visible as white spots. Recent research studies have yielded a strong mechanistic understanding of this disease. Autoreactive cytotoxic CD8+ T cells engage melanocytes and promote disease progression through the local production of IFN-γ, and IFN-γ-induced chemokines are then secreted from surrounding keratinocytes to further recruit T cells to the skin through a positive-feedback loop. Both topical and systemic treatments that block IFN-γ signaling can effectively reverse vitiligo in humans; however, disease relapse is common after stopping treatments. Autoreactive resident memory T cells are responsible for relapse, and new treatment strategies focus on eliminating these cells to promote long-lasting benefit. Here, we discuss basic, translational, and clinical research studies that provide insight into the pathogenesis of vitiligo, and how this insight has been utilized to create new targeted treatment strategies.
Assuntos
Vitiligo/etiologia , Vitiligo/terapia , Animais , Autoimunidade , Biomarcadores , Citocinas/metabolismo , Gerenciamento Clínico , Suscetibilidade a Doenças , Humanos , Memória Imunológica , Vitiligo/diagnósticoRESUMO
Although infections among vaccinated individuals lead to milder COVID-19 symptoms relative to those in unvaccinated subjects, the specificity and durability of antibody responses elicited by breakthrough cases remain unknown. Here, we demonstrate that breakthrough infections induce serum-binding and -neutralizing antibody responses that are markedly more potent, durable, and resilient to spike mutations observed in variants than those in subjects who received only 2 doses of vaccine. However, we show that breakthrough cases, subjects who were vaccinated after infection, and individuals vaccinated three times have serum-neutralizing activity of comparable magnitude and breadth, indicating that an increased number of exposures to SARS-CoV-2 antigen(s) enhance the quality of antibody responses. Neutralization of SARS-CoV was moderate, however, underscoring the importance of developing vaccines eliciting broad sarbecovirus immunity for pandemic preparedness.
RESUMO
The SARS-CoV-2 spike (S) glycoprotein contains an immunodominant receptor-binding domain (RBD) targeted by most neutralizing antibodies (Abs) in COVID-19 patient plasma. Little is known about neutralizing Abs binding to epitopes outside the RBD and their contribution to protection. Here, we describe 41 human monoclonal Abs (mAbs) derived from memory B cells, which recognize the SARS-CoV-2 S N-terminal domain (NTD) and show that a subset of them neutralize SARS-CoV-2 ultrapotently. We define an antigenic map of the SARS-CoV-2 NTD and identify a supersite (designated site i) recognized by all known NTD-specific neutralizing mAbs. These mAbs inhibit cell-to-cell fusion, activate effector functions, and protect Syrian hamsters from SARS-CoV-2 challenge, albeit selecting escape mutants in some animals. Indeed, several SARS-CoV-2 variants, including the B.1.1.7, B.1.351, and P.1 lineages, harbor frequent mutations within the NTD supersite, suggesting ongoing selective pressure and the importance of NTD-specific neutralizing mAbs for protective immunity and vaccine design.
Assuntos
Antígenos Virais/imunologia , SARS-CoV-2/imunologia , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , COVID-19/virologia , Cricetinae , Mapeamento de Epitopos , Variação Genética , Modelos Moleculares , Mutação/genética , Testes de Neutralização , Domínios Proteicos , RNA Viral/genética , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/ultraestruturaRESUMO
The receptor binding domain (RBD) of the SARS-CoV-2 spike glycoprotein mediates viral attachment to ACE2 receptor and is a major determinant of host range and a dominant target of neutralizing antibodies. Here, we experimentally measure how all amino acid mutations to the RBD affect expression of folded protein and its affinity for ACE2. Most mutations are deleterious for RBD expression and ACE2 binding, and we identify constrained regions on the RBD's surface that may be desirable targets for vaccines and antibody-based therapeutics. But a substantial number of mutations are well tolerated or even enhance ACE2 binding, including at ACE2 interface residues that vary across SARS-related coronaviruses. However, we find no evidence that these ACE2-affinity-enhancing mutations have been selected in current SARS-CoV-2 pandemic isolates. We present an interactive visualization and open analysis pipeline to facilitate use of our dataset for vaccine design and functional annotation of mutations observed during viral surveillance.
Assuntos
Simulação de Acoplamento Molecular , Mutação , Peptidil Dipeptidase A/metabolismo , Glicoproteína da Espícula de Coronavírus/genética , Enzima de Conversão de Angiotensina 2 , Sítios de Ligação , Células HEK293 , Humanos , Peptidil Dipeptidase A/química , Fenótipo , Ligação Proteica , Dobramento de Proteína , Saccharomyces cerevisiae , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismoRESUMO
KRAS mutant pancreatic ductal adenocarcinoma (PDAC) is characterized by a desmoplastic response that promotes hypovascularity, immunosuppression, and resistance to chemo- and immunotherapies. We show that a combination of MEK and CDK4/6 inhibitors that target KRAS-directed oncogenic signaling can suppress PDAC proliferation through induction of retinoblastoma (RB) protein-mediated senescence. In preclinical mouse models of PDAC, this senescence-inducing therapy produces a senescence-associated secretory phenotype (SASP) that includes pro-angiogenic factors that promote tumor vascularization, which in turn enhances drug delivery and efficacy of cytotoxic gemcitabine chemotherapy. In addition, SASP-mediated endothelial cell activation stimulates the accumulation of CD8+ T cells into otherwise immunologically "cold" tumors, sensitizing tumors to PD-1 checkpoint blockade. Therefore, in PDAC models, therapy-induced senescence can establish emergent susceptibilities to otherwise ineffective chemo- and immunotherapies through SASP-dependent effects on the tumor vasculature and immune system.
Assuntos
Envelhecimento/fisiologia , Carcinoma Ductal Pancreático/patologia , Remodelação Vascular/fisiologia , Animais , Linfócitos T CD8-Positivos/imunologia , Carcinoma Ductal Pancreático/microbiologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Quinase 4 Dependente de Ciclina/metabolismo , Quinase 6 Dependente de Ciclina/metabolismo , Regulação Neoplásica da Expressão Gênica/genética , Genes ras/genética , Humanos , Imunoterapia/métodos , Sistema de Sinalização das MAP Quinases/fisiologia , Camundongos , Neoplasias Pancreáticas/patologia , Proteína do Retinoblastoma/imunologia , Transdução de Sinais/genética , Microambiente Tumoral , Remodelação Vascular/genéticaRESUMO
We present an integrated analysis of the clinical measurements, immune cells, and plasma multi-omics of 139 COVID-19 patients representing all levels of disease severity, from serial blood draws collected during the first week of infection following diagnosis. We identify a major shift between mild and moderate disease, at which point elevated inflammatory signaling is accompanied by the loss of specific classes of metabolites and metabolic processes. Within this stressed plasma environment at moderate disease, multiple unusual immune cell phenotypes emerge and amplify with increasing disease severity. We condensed over 120,000 immune features into a single axis to capture how different immune cell classes coordinate in response to SARS-CoV-2. This immune-response axis independently aligns with the major plasma composition changes, with clinical metrics of blood clotting, and with the sharp transition between mild and moderate disease. This study suggests that moderate disease may provide the most effective setting for therapeutic intervention.
Assuntos
COVID-19 , Genômica , RNA-Seq , SARS-CoV-2 , Análise de Célula Única , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , COVID-19/sangue , COVID-19/imunologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , SARS-CoV-2/imunologia , SARS-CoV-2/metabolismo , Índice de Gravidade de DoençaRESUMO
Analysis of the specificity and kinetics of neutralizing antibodies (nAbs) elicited by SARS-CoV-2 infection is crucial for understanding immune protection and identifying targets for vaccine design. In a cohort of 647 SARS-CoV-2-infected subjects, we found that both the magnitude of Ab responses to SARS-CoV-2 spike (S) and nucleoprotein and nAb titers correlate with clinical scores. The receptor-binding domain (RBD) is immunodominant and the target of 90% of the neutralizing activity present in SARS-CoV-2 immune sera. Whereas overall RBD-specific serum IgG titers waned with a half-life of 49 days, nAb titers and avidity increased over time for some individuals, consistent with affinity maturation. We structurally defined an RBD antigenic map and serologically quantified serum Abs specific for distinct RBD epitopes leading to the identification of two major receptor-binding motif antigenic sites. Our results explain the immunodominance of the receptor-binding motif and will guide the design of COVID-19 vaccines and therapeutics.
Assuntos
Anticorpos Neutralizantes/imunologia , Mapeamento de Epitopos/métodos , Glicoproteína da Espícula de Coronavírus/imunologia , Enzima de Conversão de Angiotensina 2 , Anticorpos Monoclonais/química , Anticorpos Monoclonais/genética , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/química , Anticorpos Antivirais/sangue , Anticorpos Antivirais/química , Anticorpos Antivirais/imunologia , Reações Antígeno-Anticorpo , Betacoronavirus/imunologia , Betacoronavirus/isolamento & purificação , Betacoronavirus/metabolismo , Sítios de Ligação , COVID-19 , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Epitopos/química , Epitopos/imunologia , Humanos , Imunoglobulina A/sangue , Imunoglobulina A/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Cinética , Simulação de Dinâmica Molecular , Pandemias , Peptidil Dipeptidase A/química , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Ligação Proteica , Domínios Proteicos/imunologia , Estrutura Quaternária de Proteína , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismoRESUMO
We report a 100-million atom-scale model of an entire cell organelle, a photosynthetic chromatophore vesicle from a purple bacterium, that reveals the cascade of energy conversion steps culminating in the generation of ATP from sunlight. Molecular dynamics simulations of this vesicle elucidate how the integral membrane complexes influence local curvature to tune photoexcitation of pigments. Brownian dynamics of small molecules within the chromatophore probe the mechanisms of directional charge transport under various pH and salinity conditions. Reproducing phenotypic properties from atomistic details, a kinetic model evinces that low-light adaptations of the bacterium emerge as a spontaneous outcome of optimizing the balance between the chromatophore's structural integrity and robust energy conversion. Parallels are drawn with the more universal mitochondrial bioenergetic machinery, from whence molecular-scale insights into the mechanism of cellular aging are inferred. Together, our integrative method and spectroscopic experiments pave the way to first-principles modeling of whole living cells.
Assuntos
Células/metabolismo , Metabolismo Energético , Adaptação Fisiológica/efeitos da radiação , Trifosfato de Adenosina/metabolismo , Benzoquinonas/metabolismo , Membrana Celular/metabolismo , Membrana Celular/efeitos da radiação , Células/efeitos da radiação , Cromatóforos/metabolismo , Citocromos c2/metabolismo , Difusão , Transporte de Elétrons/efeitos da radiação , Metabolismo Energético/efeitos da radiação , Meio Ambiente , Ligação de Hidrogênio , Cinética , Luz , Simulação de Dinâmica Molecular , Fenótipo , Proteínas/metabolismo , Rhodobacter sphaeroides/fisiologia , Rhodobacter sphaeroides/efeitos da radiação , Eletricidade Estática , Estresse Fisiológico/efeitos da radiação , TemperaturaRESUMO
Continuous supply of immune cells throughout life relies on the delicate balance in the hematopoietic stem cell (HSC) pool between long-term maintenance and meeting the demands of both normal blood production and unexpected stress conditions. Here we identified distinct subsets of human long-term (LT)-HSCs that responded differently to regeneration-mediated stress: an immune checkpoint ligand CD112lo subset that exhibited a transient engraftment restraint (termed latency) before contributing to hematopoietic reconstitution and a primed CD112hi subset that responded rapidly. This functional heterogeneity and CD112 expression are regulated by INKA1 through direct interaction with PAK4 and SIRT1, inducing epigenetic changes and defining an alternative state of LT-HSC quiescence that serves to preserve self-renewal and regenerative capacity upon regeneration-mediated stress. Collectively, our data uncovered the molecular intricacies underlying HSC heterogeneity and self-renewal regulation and point to latency as an orchestrated physiological response that balances blood cell demands with preserving a stem cell reservoir.
Assuntos
Autorrenovação Celular/imunologia , Células-Tronco Hematopoéticas/fisiologia , Reconstituição Imune , Células-Tronco Multipotentes/fisiologia , Estresse Fisiológico/imunologia , Adulto , Animais , Autorrenovação Celular/genética , Células Cultivadas , Epigênese Genética/imunologia , Feminino , Sangue Fetal/citologia , Citometria de Fluxo , Técnicas de Silenciamento de Genes , Hematopoese , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Separação Imunomagnética , Recém-Nascido , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Masculino , Camundongos , Pessoa de Meia-Idade , Nectinas/metabolismo , Cultura Primária de Células , RNA-Seq , Análise de Célula Única , Sirtuína 1/metabolismo , Estresse Fisiológico/genética , Transplante Heterólogo , Quinases Ativadas por p21/genética , Quinases Ativadas por p21/metabolismoRESUMO
Evidence of the safety and protective benefits of human papillomavirus virus (HPV) vaccines as an anti-cancer measure is overwhelming. However, vaccine uptake varies widely across countries and falls short of levels needed to achieve population immunity. We highlight policy measures that would help ensure greater worldwide coverage and save lives.
Assuntos
Alphapapillomavirus/imunologia , Infecções por Papillomavirus/imunologia , Vacinas contra Papillomavirus/imunologia , Neoplasias do Colo do Útero/imunologia , Alphapapillomavirus/efeitos dos fármacos , Feminino , Saúde Global/tendências , Humanos , Infecções por Papillomavirus/prevenção & controle , Infecções por Papillomavirus/virologia , Vacinas contra Papillomavirus/economia , Vacinas contra Papillomavirus/uso terapêutico , Neoplasias do Colo do Útero/prevenção & controle , Neoplasias do Colo do Útero/virologia , Vacinação/economia , Vacinação/métodos , Vacinação/tendênciasRESUMO
Seasonal influenza vaccination elicits hemagglutinin (HA)-specific memory B (Bmem) cells, and although multiple Bmem cell populations have been characterized, considerable heterogeneity exists. We found that HA-specific human Bmem cells differed in the expression of surface marker FcRL5 and transcriptional factor T-bet. FcRL5+T-bet+ Bmem cells were transcriptionally similar to effector-like memory cells, while T-betnegFcRL5neg Bmem cells exhibited stem-like central memory properties. FcRL5+ Bmem cells did not express plasma-cell-commitment factors but did express transcriptional, epigenetic, metabolic, and functional programs that poised these cells for antibody production. Accordingly, HA+ T-bet+ Bmem cells at day 7 post-vaccination expressed intracellular immunoglobulin, and tonsil-derived FcRL5+ Bmem cells differentiated more rapidly into antibody-secreting cells (ASCs) in vitro. The T-bet+ Bmem cell response positively correlated with long-lived humoral immunity, and clonotypes from T-bet+ Bmem cells were represented in the secondary ASC response to repeat vaccination, suggesting that this effector-like population predicts influenza vaccine durability and recall potential.
Assuntos
Vacinas contra Influenza , Influenza Humana , Humanos , Influenza Humana/prevenção & controle , Formação de Anticorpos , Células B de Memória , Vacinação , Memória Imunológica , Anticorpos AntiviraisRESUMO
Diet profoundly influences physiology. Whereas over-nutrition elevates risk for disease via its influence on immunity and metabolism, caloric restriction and fasting appear to be salutogenic. Despite multiple correlations observed between diet and health, the underlying biology remains unclear. Here, we identified a fasting-induced switch in leukocyte migration that prolongs monocyte lifespan and alters susceptibility to disease in mice. We show that fasting during the active phase induced the rapid return of monocytes from the blood to the bone marrow. Monocyte re-entry was orchestrated by hypothalamic-pituitary-adrenal (HPA) axis-dependent release of corticosterone, which augmented the CXCR4 chemokine receptor. Although the marrow is a safe haven for monocytes during nutrient scarcity, re-feeding prompted mobilization culminating in monocytosis of chronologically older and transcriptionally distinct monocytes. These shifts altered response to infection. Our study shows that diet-in particular, a diet's temporal dynamic balance-modulates monocyte lifespan with consequences for adaptation to external stressors.
Assuntos
Medula Óssea , Monócitos , Camundongos , Animais , Células da Medula Óssea , Jejum , Quimiocinas/metabolismoRESUMO
Glial cells and central nervous system (CNS)-infiltrating leukocytes contribute to multiple sclerosis (MS). However, the networks that govern crosstalk among these ontologically distinct populations remain unclear. Here, we show that, in mice and humans, CNS-resident astrocytes and infiltrating CD44hiCD4+ T cells generated interleukin-3 (IL-3), while microglia and recruited myeloid cells expressed interleukin-3 receptor-É (IL-3RÉ). Astrocytic and T cell IL-3 elicited an immune migratory and chemotactic program by IL-3RÉ+ myeloid cells that enhanced CNS immune cell infiltration, exacerbating MS and its preclinical model. Multiregional snRNA-seq of human CNS tissue revealed the appearance of IL3RA-expressing myeloid cells with chemotactic programming in MS plaques. IL3RA expression by plaque myeloid cells and IL-3 amount in the cerebrospinal fluid predicted myeloid and T cell abundance in the CNS and correlated with MS severity. Our findings establish IL-3:IL-3RA as a glial-peripheral immune network that prompts immune cell recruitment to the CNS and worsens MS.
Assuntos
Esclerose Múltipla , Animais , Humanos , Camundongos , Sistema Nervoso Central , Interleucina-3 , Microglia , Neuroglia/metabolismoRESUMO
Activating mutations of FLT3 occur in about 30% of acute myeloid leukemia (AML) cases and are associated with relapse and poor prognosis. Midostaurin is the first drug approved for AML since 2000, and the first multi-kinase inhibitor approved for the FLT3-mutant subtype. To view this Bench to Bedside, open or download the PDF.
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Antineoplásicos/uso terapêutico , Aprovação de Drogas , Leucemia Mieloide Aguda/tratamento farmacológico , Estaurosporina/análogos & derivados , Antineoplásicos/química , Humanos , Leucemia Mieloide Aguda/genética , Estaurosporina/química , Estaurosporina/uso terapêutico , Estados Unidos , United States Food and Drug AdministrationRESUMO
Type 2 diabetes (T2D) is a worldwide epidemic with a medical need for additional targeted therapies. Suppression of hepatic glucose production (HGP) effectively ameliorates diabetes and can be exploited for its treatment. We hypothesized that targeting PGC-1α acetylation in the liver, a chemical modification known to inhibit hepatic gluconeogenesis, could be potentially used for treatment of T2D. Thus, we designed a high-throughput chemical screen platform to quantify PGC-1α acetylation in cells and identified small molecules that increase PGC-1α acetylation, suppress gluconeogenic gene expression, and reduce glucose production in hepatocytes. On the basis of potency and bioavailability, we selected a small molecule, SR-18292, that reduces blood glucose, strongly increases hepatic insulin sensitivity, and improves glucose homeostasis in dietary and genetic mouse models of T2D. These studies have important implications for understanding the regulatory mechanisms of glucose metabolism and treatment of T2D.
Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Gluconeogênese/efeitos dos fármacos , Hipoglicemiantes/administração & dosagem , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/antagonistas & inibidores , Acetilação , Animais , Glicemia/metabolismo , Células Cultivadas , Glucose/metabolismo , Fator 4 Nuclear de Hepatócito/metabolismo , Hepatócitos/metabolismo , Ensaios de Triagem em Larga Escala , Resistência à Insulina , Camundongos , Fatores de Transcrição de p300-CBP/metabolismoRESUMO
Memory B cells are found in lymphoid and non-lymphoid tissues, suggesting that some may be tissue-resident cells. Here we show that pulmonary influenza infection elicited lung-resident memory B cells (BRM cells) that were phenotypically and functionally distinct from their systemic counterparts. BRM cells were established in the lung early after infection, in part because their placement required local antigen encounter. Lung BRM cells, but not systemic memory B cells, contributed to early plasmablast responses following challenge infection. Following secondary infection, antigen-specific BRM cells differentiated in situ, whereas antigen-non-specific BRM cells were maintained as memory cells. These data demonstrate that BRM cells are an important component of immunity to respiratory viruses such as influenza virus and suggest that vaccines designed to elicit BRM cells must deliver antigen to the lungs.
Assuntos
Antígenos Virais/imunologia , Linfócitos B/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Pulmão/imunologia , Infecções por Orthomyxoviridae/imunologia , Orthomyxoviridae/fisiologia , Plasmócitos/imunologia , Animais , Diferenciação Celular , Células Cultivadas , Feminino , Humanos , Imunidade Humoral , Memória Imunológica , Pulmão/virologia , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos TransgênicosRESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
Understanding resistance to antibody to programmed cell death protein 1 (PD-1; anti-PD-1) is crucial for the development of reversal strategies. In anti-PD-1-resistant models, simultaneous anti-PD-1 and vaccine therapy reversed resistance, while PD-1 blockade before antigen priming abolished therapeutic outcomes. This was due to induction of dysfunctional PD-1+CD38hi CD8+ cells by PD-1 blockade in suboptimally primed CD8 cell conditions induced by tumors. This results in erroneous T cell receptor signaling and unresponsiveness to antigenic restimulation. On the other hand, PD-1 blockade of optimally primed CD8 cells prevented the induction of dysfunctional CD8 cells, reversing resistance. Depleting PD-1+CD38hi CD8+ cells enhanced therapeutic outcomes. Furthermore, non-responding patients showed more PD-1+CD38+CD8+ cells in tumor and blood than responders. In conclusion, the status of CD8+ T cell priming is a major contributor to anti-PD-1 therapeutic resistance. PD-1 blockade in unprimed or suboptimally primed CD8 cells induces resistance through the induction of PD-1+CD38hi CD8+ cells that is reversed by optimal priming. PD-1+CD38hi CD8+ cells serve as a predictive and therapeutic biomarker for anti-PD-1 treatment. Sequencing of anti-PD-1 and vaccine is crucial for successful therapy.
Assuntos
ADP-Ribosil Ciclase 1/metabolismo , Linfócitos T CD8-Positivos/imunologia , Resistencia a Medicamentos Antineoplásicos/imunologia , Glicoproteínas de Membrana/metabolismo , Neoplasias/imunologia , Receptor de Morte Celular Programada 1/imunologia , ADP-Ribosil Ciclase 1/genética , Animais , Anticorpos/imunologia , Linfócitos T CD8-Positivos/patologia , Vacinas Anticâncer/imunologia , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Humanos , Imunoterapia/métodos , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Microambiente Tumoral/imunologiaRESUMO
The factors that influence survival during severe infection are unclear. Extracellular chromatin drives pathology, but the mechanisms enabling its accumulation remain elusive. Here, we show that in murine sepsis models, splenocyte death interferes with chromatin clearance through the release of the DNase I inhibitor actin. Actin-mediated inhibition was compensated by upregulation of DNase I or the actin scavenger gelsolin. Splenocyte death and neutrophil extracellular trap (NET) clearance deficiencies were prevalent in individuals with severe COVID-19 pneumonia or microbial sepsis. Activity tracing by plasma proteomic profiling uncovered an association between low NET clearance and increased COVID-19 pathology and mortality. Low NET clearance activity with comparable proteome associations was prevalent in healthy donors with low-grade inflammation, implicating defective chromatin clearance in the development of cardiovascular disease and linking COVID-19 susceptibility to pre-existing conditions. Hence, the combination of aberrant chromatin release with defects in protective clearance mechanisms lead to poor survival outcomes.
Assuntos
COVID-19 , Sepse , Animais , Camundongos , Actinas , Cromatina , Desoxirribonuclease I , DNA , Neutrófilos , ProteômicaRESUMO
Vaccines generate high-affinity antibodies by recruiting antigen-specific B cells to germinal centers (GCs), but the mechanisms governing the recruitment to GCs on secondary challenges remain unclear. Here, using preclinical SARS-CoV and HIV mouse models, we demonstrated that the antibodies elicited during primary humoral responses shaped the naive B cell recruitment to GCs during secondary exposures. The antibodies from primary responses could either enhance or, conversely, restrict the GC participation of naive B cells: broad-binding, low-affinity, and low-titer antibodies enhanced recruitment, whereas, by contrast, the high titers of high-affinity, mono-epitope-specific antibodies attenuated cognate naive B cell recruitment. Thus, the directionality and intensity of that effect was determined by antibody concentration, affinity, and epitope specificity. Circulating antibodies can, therefore, be important determinants of antigen immunogenicity. Future vaccines may need to overcome-or could, alternatively, leverage-the effects of circulating primary antibodies on subsequent naive B cell recruitment.