RESUMEN
Multisystem inflammatory syndrome in children (MIS-C) is a severe, post-infectious sequela of SARS-CoV-2 infection1,2, yet the pathophysiological mechanism connecting the infection to the broad inflammatory syndrome remains unknown. Here we leveraged a large set of samples from patients with MIS-C to identify a distinct set of host proteins targeted by patient autoantibodies including a particular autoreactive epitope within SNX8, a protein involved in regulating an antiviral pathway associated with MIS-C pathogenesis. In parallel, we also probed antibody responses from patients with MIS-C to the complete SARS-CoV-2 proteome and found enriched reactivity against a distinct domain of the SARS-CoV-2 nucleocapsid protein. The immunogenic regions of the viral nucleocapsid and host SNX8 proteins bear remarkable sequence similarity. Consequently, we found that many children with anti-SNX8 autoantibodies also have cross-reactive T cells engaging both the SNX8 and the SARS-CoV-2 nucleocapsid protein epitopes. Together, these findings suggest that patients with MIS-C develop a characteristic immune response to the SARS-CoV-2 nucleocapsid protein that is associated with cross-reactivity to the self-protein SNX8, demonstrating a mechanistic link between the infection and the inflammatory syndrome, with implications for better understanding a range of post-infectious autoinflammatory diseases.
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Anticuerpos Antivirales , Autoanticuerpos , COVID-19 , Reacciones Cruzadas , Epítopos , Imitación Molecular , SARS-CoV-2 , Síndrome de Respuesta Inflamatoria Sistémica , Niño , Humanos , Anticuerpos Antivirales/inmunología , Autoanticuerpos/inmunología , Proteínas de la Nucleocápside de Coronavirus/química , Proteínas de la Nucleocápside de Coronavirus/inmunología , COVID-19/inmunología , COVID-19/virología , COVID-19/complicaciones , Reacciones Cruzadas/inmunología , Epítopos/inmunología , Epítopos/química , Imitación Molecular/inmunología , Fosfoproteínas/química , Fosfoproteínas/inmunología , SARS-CoV-2/química , SARS-CoV-2/inmunología , SARS-CoV-2/metabolismo , SARS-CoV-2/patogenicidad , Nexinas de Clasificación/química , Nexinas de Clasificación/inmunología , Síndrome de Respuesta Inflamatoria Sistémica/inmunología , Síndrome de Respuesta Inflamatoria Sistémica/patología , Síndrome de Respuesta Inflamatoria Sistémica/virología , Linfocitos T/inmunologíaRESUMEN
Although infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has pleiotropic and systemic effects in some individuals1-3, many others experience milder symptoms. Here, to gain a more comprehensive understanding of the distinction between severe and mild phenotypes in the pathology of coronavirus disease 2019 (COVID-19) and its origins, we performed a whole-blood-preserving single-cell analysis protocol to integrate contributions from all major immune cell types of the blood-including neutrophils, monocytes, platelets, lymphocytes and the contents of the serum. Patients with mild COVID-19 exhibit a coordinated pattern of expression of interferon-stimulated genes (ISGs)3 across every cell population, whereas these ISG-expressing cells are systemically absent in patients with severe disease. Paradoxically, individuals with severe COVID-19 produce very high titres of anti-SARS-CoV-2 antibodies and have a lower viral load compared to individuals with mild disease. Examination of the serum from patients with severe COVID-19 shows that these patients uniquely produce antibodies that functionally block the production of the ISG-expressing cells associated with mild disease, by activating conserved signalling circuits that dampen cellular responses to interferons. Overzealous antibody responses pit the immune system against itself in many patients with COVID-19, and perhaps also in individuals with other viral infections. Our findings reveal potential targets for immunotherapies in patients with severe COVID-19 to re-engage viral defence.
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Anticuerpos Antivirales/inmunología , COVID-19/inmunología , COVID-19/fisiopatología , Interferones/antagonistas & inhibidores , Interferones/inmunología , SARS-CoV-2/inmunología , SARS-CoV-2/patogenicidad , Anticuerpos Antivirales/sangre , Formación de Anticuerpos , Secuencia de Bases , COVID-19/sangre , COVID-19/virología , Femenino , Humanos , Inmunoglobulina G/inmunología , Interferones/metabolismo , Masculino , Neutrófilos/inmunología , Neutrófilos/patología , Dominios Proteicos , Receptor de Interferón alfa y beta/antagonistas & inhibidores , Receptor de Interferón alfa y beta/inmunología , Receptor de Interferón alfa y beta/metabolismo , Receptores de IgG/inmunología , Análisis de la Célula Individual , Carga Viral/inmunologíaRESUMEN
Cancer immunity is mediated by a delicate orchestration between the innate and adaptive immune system both systemically and within the tumor microenvironment. Although several adaptive immunity molecular targets have been proven clinically efficacious, stand-alone innate immunity targeting agents have not been successful in the clinic. Here, we report a nanoparticle optimized for systemic administration that combines immune agonists for TLR9, STING, and RIG-I with a melanoma-specific peptide to induce antitumor immunity. These immune agonistic nanoparticles (iaNPs) significantly enhance the activation of antigen-presenting cells to orchestrate the development and response of melanoma-sensitized T-cells. iaNP treatment not only suppressed tumor growth in an orthotopic solid tumor model, but also significantly reduced tumor burden in a metastatic animal model. This combination biomaterial-based approach to coordinate innate and adaptive anticancer immunity provides further insights into the benefits of stimulating multiple activation pathways to promote tumor regression, while also offering an important platform to effectively and safely deliver combination immunotherapies for cancer.
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Inmunidad Adaptativa/inmunología , Células Presentadoras de Antígenos/inmunología , Inmunidad Innata/inmunología , Interferón Tipo I/inmunología , Nanopartículas/administración & dosificación , Neoplasias/inmunología , Neoplasias/terapia , Animales , Línea Celular Tumoral , Femenino , Inmunoterapia/métodos , Ratones , Ratones Endogámicos C57BL , Linfocitos T/inmunología , Microambiente Tumoral/inmunologíaRESUMEN
Although B cells are implicated in multiple sclerosis (MS) pathophysiology, a predictive or diagnostic autoantibody remains elusive. In this study, the Department of Defense Serum Repository (DoDSR), a cohort of over 10 million individuals, was used to generate whole-proteome autoantibody profiles of hundreds of patients with MS (PwMS) years before and subsequently after MS onset. This analysis defines a unique cluster in approximately 10% of PwMS who share an autoantibody signature against a common motif that has similarity with many human pathogens. These patients exhibit antibody reactivity years before developing MS symptoms and have higher levels of serum neurofilament light (sNfL) compared to other PwMS. Furthermore, this profile is preserved over time, providing molecular evidence for an immunologically active preclinical period years before clinical onset. This autoantibody reactivity was validated in samples from a separate incident MS cohort in both cerebrospinal fluid and serum, where it is highly specific for patients eventually diagnosed with MS. This signature is a starting point for further immunological characterization of this MS patient subset and may be clinically useful as an antigen-specific biomarker for high-risk patients with clinically or radiologically isolated neuroinflammatory syndromes.
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Autoanticuerpos , Esclerosis Múltiple , Proteínas de Neurofilamentos , Humanos , Esclerosis Múltiple/inmunología , Esclerosis Múltiple/sangre , Autoanticuerpos/sangre , Autoanticuerpos/inmunología , Proteínas de Neurofilamentos/sangre , Proteínas de Neurofilamentos/inmunología , Biomarcadores/sangre , Estudios de Cohortes , Femenino , Masculino , Adulto , Persona de Mediana EdadRESUMEN
BACKGROUND: Adequate response to the SARS-CoV-2 vaccine represents an important treatment goal in caring for patients with multiple sclerosis (MS) during the ongoing COVID-19 pandemic. Previous data so far have demonstrated lower spike-specific IgG responses following two SARS-CoV-2 vaccinations in MS patients treated with sphingosine-1-phosphate (S1P) receptor modulators and anti-CD20 monoclonal antibodies (mAb) compared to other disease modifying therapies (DMTs). It is unknown whether subsequent vaccinations can augment antibody responses in these patients. OBJECTIVES: The goal of this observational study was to determine the effects of a third SARS-CoV-2 vaccination on antibody and T cell responses in MS patients treated with anti-CD20 mAb or S1P receptor modulators. METHODS: Vaccine responses in patients treated with anti-CD20 antibodies (ocrelizumab and ofatumumab) or S1P receptor modulators (fingolimod and siponimod) were evaluated before and after third SARS-CoV-2 vaccination as part of an ongoing longitudinal study. Total spike protein and spike receptor binding domain (RBD)-specific IgG responses were measured by Luminex bead-based assay. Spike-specific CD4+ and CD8+ T cell responses were measured by activation-induced marker expression. RESULTS: MS patients and healthy controls were enrolled before and following SARS-CoV-2 vaccination. A total of 31 MS patients (n = 10 ofatumumab, n = 13 ocrelizumab, n = 8 S1P) and 10 healthy controls were evaluated through three SARS-CoV-2 vaccinations. Compared to healthy controls, total spike IgG was significantly lower in anti-CD20 mAb-treated patients and spike RBD IgG was significantly lower in anti-CD20 mAb and S1P-treated patients following a third vaccination. While seropositivity was 100% in healthy controls after a third vaccination, total spike IgG and spike RBD IgG seropositivity were lower in ofatumumab (60% and 60%, respectively), ocrelizumab (85% and 46%, respectively), and S1P-treated patients (100% and 75%, respectively). Longer treatment duration, including prior treatment history, appeared to negatively impact antibody responses. Spike-specific CD4+ and CD8+ T cell responses were well maintained across all groups following a third vaccination. Finally, immune responses were also compared in patients who were vaccinated prior to or following ofatumumab treatment. Antibody responses were significantly higher in those patients who received their primary SARS-CoV-2 vaccination prior to initiating ofatumumab treatment. CONCLUSIONS: This study adds to the evolving understanding of SARS-CoV-2 vaccine responses in people with MS treated with disease-modifying therapies (DMTs) known to suppress humoral immunity. Our findings provide important information for optimizing vaccine immunity in at-risk MS patient populations.
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COVID-19 , Esclerosis Múltiple , Moduladores de los Receptores de fosfatos y esfingosina 1 , Humanos , Inmunidad Humoral , Vacunas contra la COVID-19 , Receptores de Esfingosina-1-Fosfato , SARS-CoV-2 , Estudios Longitudinales , Pandemias , Vacunación , Anticuerpos Monoclonales , Inmunoglobulina G , Anticuerpos AntiviralesRESUMEN
Autoimmunity is characterized by loss of tolerance to tissue-specific as well as systemic antigens, resulting in complex autoantibody landscapes. Here, we introduce and extensively validate the performance characteristics of a murine proteome-wide library for phage display immunoprecipitation and sequencing (PhIP-seq) in profiling mouse autoantibodies. This library was validated using 7 genetically distinct mouse lines across a spectrum of autoreactivity. Mice deficient in antibody production (Rag2-/- and µMT) were used to model nonspecific peptide enrichments, while cross-reactivity was evaluated using anti-ovalbumin B cell receptor-restricted OB1 mice as a proof of principle. The PhIP-seq approach was then utilized to interrogate 3 distinct autoimmune disease models. First, serum from Lyn-/- IgD+/- mice with lupus-like disease was used to identify nuclear and apoptotic bleb reactivities. Second, serum from nonobese diabetic (NOD) mice, a polygenic model of pancreas-specific autoimmunity, was enriched in peptides derived from both insulin and predicted pancreatic proteins. Lastly, Aire-/- mouse sera were used to identify numerous autoantigens, many of which were also observed in previous studies of humans with autoimmune polyendocrinopathy syndrome type 1 carrying recessive mutations in AIRE. These experiments support the use of murine proteome-wide PhIP-seq for antigenic profiling and autoantibody discovery, which may be employed to study a range of immune perturbations in mouse models of autoimmunity profiling.
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Autoanticuerpos , Bacteriófagos , Humanos , Animales , Ratones , Proteoma , Autoinmunidad , Péptidos , Ratones Endogámicos NODRESUMEN
Although B cells are implicated in multiple sclerosis (MS) pathophysiology, a predictive or diagnostic autoantibody remains elusive. Here, the Department of Defense Serum Repository (DoDSR), a cohort of over 10 million individuals, was used to generate whole-proteome autoantibody profiles of hundreds of patients with MS (PwMS) years before and subsequently after MS onset. This analysis defines a unique cluster of PwMS that share an autoantibody signature against a common motif that has similarity with many human pathogens. These patients exhibit antibody reactivity years before developing MS symptoms and have higher levels of serum neurofilament light (sNfL) compared to other PwMS. Furthermore, this profile is preserved over time, providing molecular evidence for an immunologically active prodromal period years before clinical onset. This autoantibody reactivity was validated in samples from a separate incident MS cohort in both cerebrospinal fluid (CSF) and serum, where it is highly specific for patients eventually diagnosed with MS. This signature is a starting point for further immunological characterization of this MS patient subset and may be clinically useful as an antigen-specific biomarker for high-risk patients with clinically- or radiologically-isolated neuroinflammatory syndromes.
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BACKGROUNDVaccine-elicited adaptive immunity is a prerequisite for control of SARS-CoV-2 infection. Multiple sclerosis (MS) disease-modifying therapies (DMTs) differentially target humoral and cellular immunity. A comprehensive comparison of the effects of MS DMTs on SARS-CoV-2 vaccine-specific immunity is needed, including quantitative and functional B and T cell responses.METHODSSpike-specific Ab and T cell responses were measured before and following SARS-CoV-2 vaccination in a cohort of 80 study participants, including healthy controls and patients with MS in 6 DMT groups: untreated and treated with glatiramer acetate (GA), dimethyl fumarate (DMF), natalizumab (NTZ), sphingosine-1-phosphate (S1P) receptor modulators, and anti-CD20 mAbs. Anti-spike-Ab responses were assessed by Luminex assay, VirScan, and pseudovirus neutralization. Spike-specific CD4+ and CD8+ T cell responses were characterized by activation-induced marker and cytokine expression and tetramer.RESULTSAnti-spike IgG levels were similar between healthy control participants and patients with untreated MS and those receiving GA, DMF, or NTZ but were reduced in anti-CD20 mAb- and S1P-treated patients. Anti-spike seropositivity in anti-CD20 mAb-treated patients was correlated with CD19+ B cell levels and inversely correlated with cumulative treatment duration. Spike epitope reactivity and pseudovirus neutralization were reduced in anti-CD20 mAb- and S1P-treated patients. Spike-specific CD4+ and CD8+ T cell reactivity remained robust across all groups, except in S1P-treated patients, in whom postvaccine CD4+ T cell responses were attenuated.CONCLUSIONThese findings from a large cohort of patients with MS exposed to a wide spectrum of MS immunotherapies have important implications for treatment-specific COVID-19 clinical guidelines.FUNDINGNIH grants 1K08NS107619, K08NS096117, R01AI159260, R01NS092835, R01AI131624, and R21NS108159; NMSS grants TA-1903-33713 and RG1701-26628; Westridge Foundation; Chan Zuckerberg Biohub; Maisin Foundation.
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Anticuerpos Antivirales/biosíntesis , Vacunas contra la COVID-19/inmunología , Esclerosis Múltiple/terapia , SARS-CoV-2/inmunología , Linfocitos T/inmunología , Anticuerpos Antivirales/inmunología , Humanos , Esclerosis Múltiple/inmunologíaRESUMEN
Vaccine-elicited adaptive immunity is an essential prerequisite for effective prevention and control of coronavirus 19 (COVID-19). Treatment of multiple sclerosis (MS) involves a diverse array of disease-modifying therapies (DMTs) that target antibody and cell-mediated immunity, yet a comprehensive understanding of how MS DMTs impact SARS-CoV-2 vaccine responses is lacking. We completed a detailed analysis of SARS-CoV-2 vaccine-elicited spike antigen-specific IgG and T cell responses in a cohort of healthy controls and MS participants in six different treatment categories. Two specific DMT types, sphingosine-1-phosphate (S1P) receptor modulators and anti-CD20 monoclonal antibodies (mAb), resulted in significantly reduced spike-specific IgG responses. Longer duration of anti-CD20 mAb treatment prior to SARS-CoV-2 vaccination were associated with absent antibody responses. Except for reduced CD4+ T cell responses in S1P-treated patients, spike-specific CD4+ and CD8+ T cell reactivity remained robust across all MS treatment types. These findings have important implications for clinical practice guidelines and vaccination recommendations in MS patients and other immunosuppressed populations.
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Importance: Neuropsychiatric manifestations of COVID-19 have been reported in the pediatric population. Objective: To determine whether anti-SARS-CoV-2 and autoreactive antibodies are present in the cerebrospinal fluid (CSF) of pediatric patients with COVID-19 and subacute neuropsychiatric dysfunction. Design, Setting, and Participants: This case series includes 3 patients with recent SARS-CoV-2 infection as confirmed by reverse transcriptase-polymerase chain reaction or IgG serology with recent exposure history who were hospitalized at the University of California, San Francisco Benioff Children's Hospital and for whom a neurology consultation was requested over a 5-month period in 2020. During this period, 18 total children were hospitalized and tested positive for acute SARS-CoV-2 infection by reverse transcriptase-polymerase chain reaction or rapid antigen test. Main Outcomes and Measures: Detection and characterization of CSF anti-SARS-CoV-2 IgG and antineural antibodies. Results: Of 3 included teenaged patients, 2 patients had intrathecal anti-SARS-CoV-2 antibodies. CSF IgG from these 2 patients also indicated antineural autoantibodies on anatomic immunostaining. Autoantibodies targeting transcription factor 4 (TCF4) in 1 patient who appeared to have a robust response to immunotherapy were also validated. Conclusions and Relevance: Pediatric patients with COVID-19 and prominent subacute neuropsychiatric symptoms, ranging from severe anxiety to delusional psychosis, may have anti-SARS-CoV-2 and antineural antibodies in their CSF and may respond to immunotherapy.
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Anticuerpos Antivirales/líquido cefalorraquídeo , Autoanticuerpos/líquido cefalorraquídeo , COVID-19/complicaciones , COVID-19/inmunología , Trastornos Mentales/líquido cefalorraquídeo , Trastornos Mentales/etiología , Enfermedades del Sistema Nervioso/líquido cefalorraquídeo , Enfermedades del Sistema Nervioso/etiología , Adolescente , Animales , Ansiedad/etiología , Ansiedad/psicología , Autoinmunidad , Femenino , Humanos , Masculino , Fumar Marihuana/inmunología , Ratones , Trastornos del Movimiento/etiología , Examen Neurológico , Factor de Transcripción 4/inmunologíaRESUMEN
Individuals with coronavirus disease 2019 (COVID-19) frequently develop neurological symptoms, but the biological underpinnings of these phenomena are unknown. Through single-cell RNA sequencing (scRNA-seq) and cytokine analyses of cerebrospinal fluid (CSF) and blood from individuals with COVID-19 with neurological symptoms, we find compartmentalized, CNS-specific T cell activation and B cell responses. All affected individuals had CSF anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies whose target epitopes diverged from serum antibodies. In an animal model, we find that intrathecal SARS-CoV-2 antibodies are present only during brain infection and not elicited by pulmonary infection. We produced CSF-derived monoclonal antibodies from an individual with COVID-19 and found that these monoclonal antibodies (mAbs) target antiviral and antineural antigens, including one mAb that reacted to spike protein and neural tissue. CSF immunoglobulin G (IgG) from 5 of 7 patients showed antineural reactivity. This immune survey reveals evidence of a compartmentalized immune response in the CNS of individuals with COVID-19 and suggests a role of autoimmunity in neurologic sequelae of COVID-19.
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Systemic cytokine therapy is limited by toxicity due to activation of unwanted immune cells in off-target tissues. Injectable nanomaterials that interact with the immune system have potential to offer improved pharmacokinetics and cell specificity compared to systemic cytokine therapy by instead capturing and potentiating endogenous cytokine. Here we demonstrate the use of high aspect ratio polycaprolactone nanowires conjugated to cytokine-binding antibodies that assemble into porous matrices when injected into the subcutaneous space. Nanowires are well tolerated in vivo over several weeks, incite minimal foreign body response and resist clearance. Nanowires conjugated with JES6-1, an anti-interleukin-2 (IL-2) antibody, were designed to capture endogenous IL-2 and selectively activate tissue resident regulatory T cells (Tregs). Together these nanowire-antibody matrices were capable of sequestering endogenous IL-2 in the skin and were successful in rebalancing local immune compartments to a more suppressive, Treg-mediated phenotype in both wild type and transgenic murine autoimmune disease models.
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Enfermedades Autoinmunes , Citocinas , Animales , Anticuerpos , Enfermedades Autoinmunes/tratamiento farmacológico , Interleucina-2 , Ratones , Linfocitos T ReguladoresRESUMEN
Comprehensive understanding of the serological response to SARS-CoV-2 infection is important for both pathophysiologic insight and diagnostic development. Here, we generate a pan-human coronavirus programmable phage display assay to perform proteome-wide profiling of coronavirus antigens enriched by 98 COVID-19 patient sera. Next, we use ReScan, a method to efficiently sequester phage expressing the most immunogenic peptides and print them onto paper-based microarrays using acoustic liquid handling, which isolates and identifies nine candidate antigens, eight of which are derived from the two proteins used for SARS-CoV-2 serologic assays: spike and nucleocapsid proteins. After deployment in a high-throughput assay amenable to clinical lab settings, these antigens show improved specificity over a whole protein panel. This proof-of-concept study demonstrates that ReScan will have broad applicability for other emerging infectious diseases or autoimmune diseases that lack a valid biomarker, enabling a seamless pipeline from antigen discovery to diagnostic using one recombinant protein source.
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Antígenos Virales/inmunología , Prueba Serológica para COVID-19/métodos , COVID-19/diagnóstico , SARS-CoV-2/aislamiento & purificación , Anticuerpos Antivirales/sangre , COVID-19/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Biblioteca de Péptidos , Análisis por Matrices de Proteínas , Proteoma/inmunología , Reproducibilidad de los Resultados , SARS-CoV-2/inmunología , Sensibilidad y Especificidad , Proteínas Virales/inmunologíaRESUMEN
One third of COVID-19 patients develop significant neurological symptoms, yet SARS-CoV-2 is rarely detected in central nervous system (CNS) tissue, suggesting a potential role for parainfectious processes, including neuroimmune responses. We therefore examined immune parameters in cerebrospinal fluid (CSF) and blood samples from a cohort of patients with COVID-19 and significant neurological complications. We found divergent immunological responses in the CNS compartment, including increased levels of IL-12 and IL-12-associated innate and adaptive immune cell activation. Moreover, we found increased proportions of B cells in the CSF relative to the periphery and evidence of clonal expansion of CSF B cells, suggesting a divergent intrathecal humoral response to SARS-CoV-2. Indeed, all COVID-19 cases examined had anti-SARS-CoV-2 IgG antibodies in the CSF whose target epitopes diverged from serum antibodies. We directly examined whether CSF resident antibodies target self-antigens and found a significant burden of CNS autoimmunity, with the CSF from most patients recognizing neural self-antigens. Finally, we produced a panel of monoclonal antibodies from patients' CSF and show that these target both anti-viral and anti-neural antigens-including one mAb specific for the spike protein that also recognizes neural tissue. This exploratory immune survey reveals evidence of a compartmentalized and self-reactive immune response in the CNS meriting a more systematic evaluation of neurologically impaired COVID-19 patients.
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While SARS-CoV-2 infection has pleiotropic and systemic effects in some patients, many others experience milder symptoms. We sought a holistic understanding of the severe/mild distinction in COVID-19 pathology, and its origins. We performed a wholeblood preserving single-cell analysis protocol to integrate contributions from all major cell types including neutrophils, monocytes, platelets, lymphocytes and the contents of serum. Patients with mild COVID-19 disease display a coordinated pattern of interferonstimulated gene (ISG) expression across every cell population and these cells are systemically absent in patients with severe disease. Severe COVID-19 patients also paradoxically produce very high anti-SARS-CoV-2 antibody titers and have lower viral load as compared to mild disease. Examination of the serum from severe patients demonstrates that they uniquely produce antibodies with multiple patterns of specificity against interferon-stimulated cells and that those antibodies functionally block the production of the mild disease-associated ISG-expressing cells. Overzealous and autodirected antibody responses pit the immune system against itself in many COVID-19 patients and this defines targets for immunotherapies to allow immune systems to provide viral defense.
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While SARS-CoV-2 infection has pleiotropic and systemic effects in some patients, many others experience milder symptoms. We sought a holistic understanding of the severe/mild distinction in COVID-19 pathology, and its origins. We performed a whole-blood preserving single-cell analysis protocol to integrate contributions from all major cell types including neutrophils, monocytes, platelets, lymphocytes and the contents of serum. Patients with mild COVID-19 disease display a coordinated pattern of interferon-stimulated gene (ISG) expression across every cell population and these cells are systemically absent in patients with severe disease. Severe COVID-19 patients also paradoxically produce very high anti-SARS-CoV-2 antibody titers and have lower viral load as compared to mild disease. Examination of the serum from severe patients demonstrates that they uniquely produce antibodies with multiple patterns of specificity against interferon-stimulated cells and that those antibodies functionally block the production of the mild disease-associated ISG-expressing cells. Overzealous and auto-directed antibody responses pit the immune system against itself in many COVID-19 patients and this defines targets for immunotherapies to allow immune systems to provide viral defense. ONE SENTENCE SUMMARY: In severe COVID-19 patients, the immune system fails to generate cells that define mild disease; antibodies in their serum actively prevents the successful production of those cells.
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Plexitonic nanoparticles offer variable optical properties through tunable excitations, in addition to electric field enhancements that far exceed molecular resonators. This study demonstrates a way to design an ultrabright surface-enhanced Raman spectroscopy (SERS) signal while simultaneously quenching the fluorescence background through silica encapsulation of the semiconductor-metal composite nanoparticles. Using a multistep approach, a J-aggregate-forming organic dye is assembled on the surface of gold nanoparticles using a cationic linker. Excitonic resonance of the J-aggregate-metal system shows an enhanced SERS signal at an appropriate excitation wavelength. Further encapsulation of the decorated particles in silica shows a significant reduction in the fluorescence signal of the Raman spectra (5× reduction) and an increase in Raman scattering (7× enhancement) when compared to phospholipid encapsulation. This reduction in fluorescence is important for maximizing the useful SERS enhancement from the particle, which shows a signal increase on the order of 104 times greater than J-aggregated dye in solution and 24 times greater than Oxonica S421 SERS tag. The silica layer also serves to promote colloidal stability. The combination of reduced fluorescence background, enhanced SERS intensity, and temporal stability makes these particles highly distinguishable with potential to enable high-throughput applications such as SERS flow cytometry.
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Injectable nanomaterials that interact with the host immune system without surgical intervention present spatially anchored complements to cell transplantation and could offer improved pharmacokinetics compared to systemic cytokine therapy. Here we demonstrate fabrication of high aspect ratio polycaprolactone nanowires coupled with cytokine-binding antibodies that assemble into porous matrices when injected into the subcutaneous space. These structures are fabricated using a nanotemplating technique that allows for tunability of particle dimensions and utilize a straightforward maleimide conjugation chemistry to allow site-specific coupling to proteins. Nanowires are well tolerated in vivo and incite minimal inflammatory infiltrate. Nanowires conjugated with antibodies were designed to capture and potentiate endogenous interleukin-2 (IL-2), an important leukocyte activating cytokine. Together these nanowire-antibody matrices were capable of localizing endogenous IL-2 in the skin and activated targeted specific natural killer and T cell subsets, demonstrating both tissue- and cell-specific immune activation. These self-assembling nanowire matrices show promise as scaffolds to present engineered, local receptor-ligand interactions for cytokine-mediated disease.