RESUMEN
The emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and onset of the coronavirus disease-19 (COVID-19) pandemic led to an immediate need for therapeutic treatment options. Therapeutic antibodies were developed to fill a gap when traditional antivirals were not available. In late 2020, the United States Government undertook an effort to compare candidate therapeutic antibodies in virus neutralization assays and in the hamster model of SARS-CoV-2 infection. With the emergence of SARS-CoV-2 variants, the effort expanded to evaluate the efficacy of nearly 50 products against major variants. A subset of products was further evaluated for therapeutic efficacy in hamsters. Here we report results of the hamster studies, including pathogenicity with multiple variants, neutralization capacity of products, and efficacy testing of products against Delta and Omicron variants. These studies demonstrate the loss of efficacy of early products with variant emergence and support the use of the hamster model for evaluating therapeutics.
RESUMEN
Lung-tissue-resident memory (TRM) CD8+ T cells are critical for heterosubtypic immunity against influenza virus (IAV) reinfection. How TRM cells surveil the lung, respond to infection, and interact with other cells remains unresolved. Here, we used IAV infection of mice in combination with intravital and static imaging to define the spatiotemporal dynamics of lung TRM cells before and after recall infection. CD69+CD103+ TRM cells preferentially localized to lung sites of prior IAV infection, where they exhibited patrolling behavior. After rechallenge, lung TRM cells formed tight clusters in an antigen-dependent manner. Transcriptomic analysis of IAV-specific TRM cells revealed the expression of several factors that regulate myeloid cell biology. In vivo rechallenge experiments demonstrated that protection elicited by TRM cells is orchestrated in part by interferon (IFN)-γ-mediated recruitment of inflammatory monocytes into the lungs. Overall, these data illustrate the dynamic landscapes of CD103+ lung TRM cells that mediate early protective immunity against IAV infection.
Asunto(s)
Antígenos CD , Linfocitos T CD8-positivos , Memoria Inmunológica , Virus de la Influenza A , Cadenas alfa de Integrinas , Pulmón , Células T de Memoria , Infecciones por Orthomyxoviridae , Animales , Pulmón/inmunología , Pulmón/virología , Infecciones por Orthomyxoviridae/inmunología , Linfocitos T CD8-positivos/inmunología , Ratones , Memoria Inmunológica/inmunología , Cadenas alfa de Integrinas/metabolismo , Virus de la Influenza A/inmunología , Antígenos CD/metabolismo , Células T de Memoria/inmunología , Ratones Endogámicos C57BL , Interferón gamma/metabolismo , Interferón gamma/inmunología , Microscopía Intravital , Monocitos/inmunologíaRESUMEN
Detection of the physiological response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is challenging in the absence of overt clinical signs but remains necessary to understand a full subclinical disease spectrum. In this study, our objective was to use radiomics (from computed tomography images) and blood biomarkers to predict SARS-CoV-2 infection in a nonhuman primate model (NHP) with inapparent clinical disease. To accomplish this aim, we built machine-learning models to predict SARS-CoV-2 infection in a NHP model of subclinical disease using baseline-normalized radiomic and blood sample analyses data from SARS-CoV-2-exposed and control (mock-exposed) crab-eating macaques. We applied a novel adaptation of the minimum redundancy maximum relevance (mRMR) feature-selection technique, called mRMR-permute, for statistically-thresholded and unbiased feature selection. Through performance comparison of eight machine-learning models trained on 14 feature sets, we demonstrated that a logistic regression model trained on the mRMR-permute feature set can predict SARS-CoV-2 infection with very high accuracy. Eighty-nine percent of mRMR-permute selected features had strong and significant class effects. Through this work, we identified a key set of radiomic and blood biomarkers that can be used to predict infection status even in the absence of clinical signs. Furthermore, we proposed and demonstrated the utility of a novel feature-selection technique called mRMR-permute. This work lays the foundation for the prediction and classification of SARS-CoV-2 disease severity.
Asunto(s)
COVID-19 , Animales , COVID-19/diagnóstico por imagen , SARS-CoV-2 , Biomarcadores , Aprendizaje Automático , PrimatesRESUMEN
BACKGROUND: Existing models of Ebola virus infection have not fully characterized the pathophysiology of shock in connection with daily virologic, clinical, and immunologic parameters. We implemented a nonhuman primate critical care model to investigate these associations. METHODS: Two rhesus macaques received a target dose of 1000 plaque-forming units of Ebola virus intramuscularly with supportive care initiated on day 3. High-dimensional spectral cytometry was used to phenotype neutrophils and peripheral blood mononuclear cells daily. RESULTS: We observed progressive vasodilatory shock with preserved cardiac function following viremia onset on day 5. Multiorgan dysfunction began on day 6 coincident with the nadir of circulating neutrophils. Consumptive coagulopathy and anemia occurred on days 7 to 8 along with irreversible shock, followed by death. The monocyte repertoire began shifting on day 4 with a decline in classical and expansion of double-negative monocytes. A selective loss of CXCR3-positive B and T cells, expansion of naive B cells, and activation of natural killer cells followed viremia onset. CONCLUSIONS: Our model allows for high-fidelity characterization of the pathophysiology of acute Ebola virus infection with host innate and adaptive immune responses, which may advance host-targeted therapy design and evaluation for use after the onset of multiorgan failure.
Asunto(s)
Ebolavirus , Fiebre Hemorrágica Ebola , Animales , Humanos , Macaca mulatta , Leucocitos Mononucleares , Viremia , Cuidados CríticosRESUMEN
This study compared disease progression of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in three different models of golden hamsters: aged (≈60 weeks old) wild-type (WT), young (6 weeks old) WT, and adult (14-22 weeks old) hamsters expressing the human-angiotensin-converting enzyme 2 (hACE2) receptor. After intranasal (IN) exposure to the SARS-CoV-2 Washington isolate (WA01/2020), 2-deoxy-2-[fluorine-18]fluoro-D-glucose positron emission tomography with computed tomography (18F-FDG PET/CT) was used to monitor disease progression in near real time and animals were euthanized at pre-determined time points to directly compare imaging findings with other disease parameters associated with coronavirus disease 2019 (COVID-19). Consistent with histopathology, 18F-FDG-PET/CT demonstrated that aged WT hamsters exposed to 105 plaque forming units (PFU) developed more severe and protracted pneumonia than young WT hamsters exposed to the same (or lower) dose or hACE2 hamsters exposed to a uniformly lethal dose of virus. Specifically, aged WT hamsters presented with a severe interstitial pneumonia through 8 d post-exposure (PE), while pulmonary regeneration was observed in young WT hamsters at that time. hACE2 hamsters exposed to 100 or 10 PFU virus presented with a minimal to mild hemorrhagic pneumonia but succumbed to SARS-CoV-2-related meningoencephalitis by 6 d PE, suggesting that this model might allow assessment of SARS-CoV-2 infection on the central nervous system (CNS). Our group is the first to use (18F-FDG) PET/CT to differentiate respiratory disease severity ranging from mild to severe in three COVID-19 hamster models. The non-invasive, serial measure of disease progression provided by PET/CT makes it a valuable tool for animal model characterization.
Asunto(s)
COVID-19 , Neumonía , Humanos , Animales , Cricetinae , COVID-19/diagnóstico por imagen , SARS-CoV-2 , Fluorodesoxiglucosa F18 , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Enzima Convertidora de Angiotensina 2 , Tomografía de Emisión de Positrones , Mesocricetus , Progresión de la EnfermedadRESUMEN
Despite increasing evidence that uveitis is common and consequential in survivors of Ebola virus disease (EVD), the host-pathogen determinants of the clinical phenotype are undefined, including the pathogenetic role of persistent viral antigen, ocular tissue-specific immune responses, and histopathologic characterization. Absent sampling of human intraocular fluids and tissues, these questions might be investigated in animal models of disease; however, challenges intrinsic to the nonhuman primate model and the animal biosafety level 4 setting have historically limited inquiry. In a rhesus monkey survivor of experimental Ebola virus (EBOV) infection, we observed and documented the clinical, virologic, immunologic, and histopathologic features of severe uveitis. Here we show the clinical natural history, resultant ocular pathology, intraocular antigen-specific antibody detection, and persistent intraocular EBOV RNA detected long after clinical resolution. The association of persistent EBOV RNA as a potential driver of severe immunopathology has pathophysiologic implications for understanding, preventing, and mitigating vision-threatening uveitis in EVD survivors.
Asunto(s)
Ebolavirus , Fiebre Hemorrágica Ebola , Uveítis , Animales , Humanos , Fiebre Hemorrágica Ebola/complicaciones , Ebolavirus/fisiología , Macaca mulatta , Uveítis/complicaciones , Uveítis/diagnóstico , ARNRESUMEN
Recent outbreaks of Ebola have brought to the forefront the need for focused therapeutic treatments. In this issue of Cell, Milligan and colleagues build on previous studies of antibody treatments for Ebola virus disease, uncovering broad synergistic protective immunity when administered in combination (as antibody cocktails).
Asunto(s)
Ebolavirus , Fiebre Hemorrágica Ebola , Anticuerpos Monoclonales/inmunología , Anticuerpos Neutralizantes/inmunología , Anticuerpos Neutralizantes/uso terapéutico , Anticuerpos Antivirales/inmunología , Anticuerpos Antivirales/uso terapéutico , Ebolavirus/inmunología , Epítopos/inmunología , Fiebre Hemorrágica Ebola/tratamiento farmacológico , Fiebre Hemorrágica Ebola/inmunología , Fiebre Hemorrágica Ebola/prevención & control , HumanosRESUMEN
Circulating memory CD8 T cell trafficking and protective capacity during liver-stage malaria infection remains undefined. We find that effector memory CD8 T cells (Tem) infiltrate the liver within 6 hours after malarial or bacterial infections and mediate pathogen clearance. Tem recruitment coincides with rapid transcriptional upregulation of inflammatory genes in Plasmodium-infected livers. Recruitment requires CD8 T cell-intrinsic LFA-1 expression and the presence of liver phagocytes. Rapid Tem liver infiltration is distinct from recruitment to other non-lymphoid tissues in that it occurs both in the absence of liver tissue resident memory "sensing-and-alarm" function and â¼42 hours earlier than in lung infection by influenza virus. These data demonstrate relevance for Tem in protection against malaria and provide generalizable mechanistic insights germane to control of liver infections.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Memoria Inmunológica , Hígado/inmunología , Malaria/inmunología , Plasmodium berghei/inmunología , Animales , Linfocitos T CD8-positivos/metabolismo , Linfocitos T CD8-positivos/microbiología , Linfocitos T CD8-positivos/parasitología , Modelos Animales de Enfermedad , Femenino , Interacciones Huésped-Parásitos , Listeria monocytogenes/inmunología , Listeria monocytogenes/patogenicidad , Listeriosis/sangre , Listeriosis/inmunología , Listeriosis/microbiología , Hígado/metabolismo , Hígado/microbiología , Hígado/parasitología , Antígeno-1 Asociado a Función de Linfocito/metabolismo , Malaria/sangre , Malaria/parasitología , Masculino , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Transgénicos , Carga de Parásitos , Fagocitos/inmunología , Fagocitos/metabolismo , Fagocitos/microbiología , Fagocitos/parasitología , Plasmodium berghei/patogenicidad , Factores de TiempoRESUMEN
Sepsis reduces the number and function of memory CD8 T cells within the host, contributing to the long-lasting state of immunoparalysis. Interestingly, the relative susceptibility of memory CD8 T cell subsets to quantitative/qualitative changes differ after cecal ligation and puncture (CLP)-induced sepsis. Compared with circulatory memory CD8 T cells (TCIRCM), moderate sepsis (0-10% mortality) does not result in numerical decline of CD8 tissue-resident memory T cells (TRM), which retain their "sensing and alarm" IFN-γ-mediated effector function. To interrogate this biologically important dichotomy, vaccinia virus-immune C57BL/6 (B6) mice containing CD8 TCIRCM and skin TRM underwent moderate or severe (â¼50% mortality) sepsis. Severe sepsis led to increased morbidity and mortality characterized by increased inflammation compared with moderate CLP or sham controls. Severe CLP mice also displayed increased vascular permeability in the ears. Interestingly, skin CD103+ CD8 TRM, detected by i.v. exclusion or two-photon microscopy, underwent apoptosis and subsequent numerical loss following severe sepsis, which was not observed in mice that experienced moderate CLP or sham surgeries. Consequently, severe septic mice showed diminished CD8 T cell-mediated protection to localized skin reinfection. Finally, the relationship between severity of sepsis and demise in circulatory versus tissue-embedded memory CD8 T cell populations was confirmed by examining tumor-infiltrating and nonspecific CD8 T cells in B16 melanoma tumors. Thus, sepsis can differentially affect the presence and function of Ag-specific CD8 T cells that reside inside tissues/tumors depending on the severity of the insult, a notion with direct relevance to sepsis survivors and their ability to mount protective memory CD8 T cell-dependent responses to localized Ag re-encounter.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Coriomeningitis Linfocítica/inmunología , Virus de la Coriomeningitis Linfocítica/fisiología , Sepsis/inmunología , Subgrupos de Linfocitos T/inmunología , Animales , Circulación Sanguínea , Células Cultivadas , Progresión de la Enfermedad , Humanos , Memoria Inmunológica , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Especificidad de ÓrganosRESUMEN
Protective lung tissue-resident memory CD8+T cells (Trm) form after influenza A virus (IAV) infection. We show that IAV infection of mice generates CD69+CD103+and other memory CD8+T cell populations in lung-draining mediastinal lymph nodes (mLNs) from circulating naive or memory CD8+T cells. Repeated antigen exposure, mimicking seasonal IAV infections, generates quaternary memory (4M) CD8+T cells that protect mLN from viral infection better than 1M CD8+T cells. Better protection by 4M CD8+T cells associates with enhanced granzyme A/B expression and stable maintenance of mLN CD69+CD103+4M CD8+T cells, vs the steady decline of CD69+CD103+1M CD8+T cells, paralleling the durability of protective CD69+CD103+4M vs 1M in the lung after IAV infection. Coordinated upregulation in canonical Trm-associated genes occurs in circulating 4M vs 1M populations without the enrichment of canonical downregulated Trm genes. Thus, repeated antigen exposure arms circulating memory CD8+T cells with enhanced capacity to form long-lived populations of Trm that enhance control of viral infections of the mLN.
Asunto(s)
Linfocitos T CD8-positivos , Ganglios Linfáticos , Animales , Antígenos CD/genética , Antígenos CD/inmunología , Antígenos CD/metabolismo , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/inmunología , Células Cultivadas , Femenino , Virus de la Influenza A/inmunología , Pulmón/citología , Pulmón/inmunología , Ganglios Linfáticos/citología , Ganglios Linfáticos/inmunología , Ratones , Ratones Endogámicos C57BL , Infecciones por Orthomyxoviridae/inmunología , Transcriptoma/genéticaRESUMEN
Neurotropic strains of mouse hepatitis virus (MHV), a coronavirus, cause acute and chronic demyelinating encephalomyelitis with similarities to the human disease multiple sclerosis. Here, using a lineage-tracking system, we show that some cells, primarily oligodendrocytes (OLs) and oligodendrocyte precursor cells (OPCs), survive the acute MHV infection, are associated with regions of demyelination, and persist in the central nervous system (CNS) for at least 150 d. These surviving OLs express major histocompatibility complex (MHC) class I and other genes associated with an inflammatory response. Notably, the extent of inflammatory cell infiltration was variable, dependent on anatomic location within the CNS, and without obvious correlation with numbers of surviving cells. We detected more demyelination in regions with larger numbers of T cells and microglia/macrophages compared to those with fewer infiltrating cells. Conversely, in regions with less inflammation, these previously infected OLs more rapidly extended processes, consistent with normal myelinating function. Together, these results show that OLs are inducers as well as targets of the host immune response and demonstrate how a CNS infection, even after resolution, can induce prolonged inflammatory changes with CNS region-dependent impairment in remyelination.
Asunto(s)
Sistema Nervioso Central/inmunología , Infecciones por Coronavirus/complicaciones , Enfermedades Desmielinizantes/etiología , Oligodendroglía/inmunología , Animales , Infecciones por Coronavirus/inmunología , Antígenos de Histocompatibilidad Clase I/metabolismo , Proteínas Luminiscentes , Masculino , Ratones , Virus de la Hepatitis Murina , Oligodendroglía/metabolismo , Proteína Fluorescente RojaRESUMEN
Plasmodium sporozoites inoculated by mosquitoes migrate to the liver and infect hepatocytes prior to release of merozoites that initiate symptomatic blood-stage malaria. Plasmodium parasites are thought to be restricted to hepatocytes throughout this obligate liver stage of development, and how liver-stage-expressed antigens prime productive CD8 T cell responses remains unknown. We found that a subset of liver-infiltrating monocyte-derived CD11c+ cells co-expressing F4/80, CD103, CD207, and CSF1R acquired parasites during the liver stage of malaria, but only after initial hepatocyte infection. These CD11c+ cells found in the infected liver and liver-draining lymph nodes exhibited transcriptionally and phenotypically enhanced antigen-presentation functions and primed protective CD8 T cell responses against Plasmodium liver-stage-restricted antigens. Our findings highlight a previously unrecognized aspect of Plasmodium biology and uncover the fundamental mechanism by which CD8 T cell responses are primed against liver-stage malaria antigens.
Asunto(s)
Presentación de Antígeno , Linfocitos T CD8-positivos/inmunología , Hepatocitos/parasitología , Inmunidad Celular , Hígado/inmunología , Malaria/inmunología , Monocitos/parasitología , Antígeno CD11c/análisis , Hígado/parasitología , Monocitos/química , Monocitos/inmunología , Plasmodium/inmunologíaRESUMEN
Previous studies have provided evidence that IL-15 expression within human tumors is crucial for optimal antitumor responses; however, the regulation of IL-15 within the tumor microenvironment (TME) is unclear. We report herein, in analyses of mice implanted with various tumor cell lines, soluble IL-15/IL-15Rα complexes (sIL-15 complexes) are abundant in the interstitial fluid of tumors with expression preceding the infiltration of tumor-infiltrating lymphocytes. Moreover, IL-15 as well as type I IFN, which regulates IL-15, was required for establishing normal numbers of CD8 T cells and natural killer cells in tumors. Depending on tumor type, both the tumor and the stroma are sources of sIL-15 complexes. In analyses of IL-15 reporter mice, most myeloid cells in the TME express IL-15 with CD11b+Ly6Chi cells being the most abundant, indicating there is a large source of IL-15 protein in tumors that lies sequestered within the tumor stroma. Despite the abundance of IL-15-expressing cells, the relative levels of sIL-15 complexes are low in advanced tumors but can be up-regulated by local stimulator of IFN genes (STING) activation. Furthermore, while treatment of tumors with STING agonists leads to tumor regression, optimal STING-mediated immunity and regression of distant secondary tumors required IL-15 expression. Overall, our study reveals the dynamic regulation of IL-15 in the TME and its importance in antitumor immunity. These findings provide insight into an unappreciated attribute of the tumor landscape that contributes to antitumor immunity, which can be manipulated therapeutically to enhance antitumor responses.
Asunto(s)
Regulación Neoplásica de la Expresión Génica/inmunología , Interleucina-15/inmunología , Melanoma/inmunología , Proteínas de Neoplasias/inmunología , Microambiente Tumoral/inmunología , Animales , Línea Celular Tumoral , Inflamación/genética , Inflamación/inmunología , Inflamación/patología , Interleucina-15/genética , Melanoma/genética , Melanoma/patología , Proteínas de la Membrana/genética , Proteínas de la Membrana/inmunología , Ratones , Ratones Noqueados , Proteínas de Neoplasias/genética , Receptores de Interleucina-15/genética , Receptores de Interleucina-15/inmunología , Microambiente Tumoral/genéticaRESUMEN
Anticancer vaccination is a promising approach to increase the efficacy of cytotoxic T lymphocyte-associated protein 4 (CTLA-4) and programmed death ligand 1 (PD-L1) checkpoint blockade therapies. However, the landmark FDA registration trial for anti-CTLA-4 therapy (ipilimumab) revealed a complete lack of benefit of adding vaccination with gp100 peptide formulated in incomplete Freund's adjuvant (IFA). Here, using a mouse model of melanoma, we found that gp100 vaccination induced gp100-specific effector T cells (Teffs), which dominantly forced trafficking of anti-CTLA-4-induced, non-gp100-specific Teffs away from the tumor, reducing tumor control. The inflamed vaccination site subsequently also sequestered and destroyed anti-CTLA-4-induced Teffs with specificities for tumor antigens other than gp100, reducing the antitumor efficacy of anti-CTLA-4 therapy. Mechanistically, Teffs at the vaccination site recruited inflammatory monocytes, which in turn attracted additional Teffs in a vicious cycle mediated by IFN-γ, CXCR3, ICAM-1, and CCL2, dependent on IFA formulation. In contrast, nonpersistent vaccine formulations based on dendritic cells, viral vectors, or water-soluble peptides potently synergized with checkpoint blockade of both CTLA-4 and PD-L1 and induced complete tumor regression, including in settings of primary resistance to dual checkpoint blockade. We conclude that cancer vaccine formulation can dominantly determine synergy, or lack thereof, with CTLA-4 and PD-L1 checkpoint blockade therapy for cancer.
Asunto(s)
Antígeno B7-H1/inmunología , Antígeno CTLA-4/inmunología , Vacunas contra el Cáncer/farmacología , Puntos de Control del Ciclo Celular/inmunología , Melanoma/terapia , Neoplasias Experimentales/terapia , Péptidos/inmunología , Antígeno gp100 del Melanoma/farmacología , Animales , Antígeno B7-H1/genética , Antígeno CTLA-4/genética , Vacunas contra el Cáncer/inmunología , Puntos de Control del Ciclo Celular/efectos de los fármacos , Puntos de Control del Ciclo Celular/genética , Línea Celular Tumoral , Quimiocina CCL2/genética , Quimiocina CCL2/inmunología , Células Dendríticas/inmunología , Células Dendríticas/patología , Molécula 1 de Adhesión Intercelular/genética , Molécula 1 de Adhesión Intercelular/inmunología , Melanoma/genética , Melanoma/inmunología , Melanoma/patología , Ratones , Ratones Transgénicos , Monocitos/inmunología , Monocitos/patología , Neoplasias Experimentales/genética , Neoplasias Experimentales/inmunología , Neoplasias Experimentales/patología , Péptidos/farmacología , Receptores CXCR3/genética , Receptores CXCR3/inmunología , Linfocitos T Reguladores/inmunología , Linfocitos T Reguladores/patología , Antígeno gp100 del Melanoma/inmunologíaRESUMEN
Malaria, caused by the protozoan Plasmodium, is a devastating mosquito-borne disease with the potential to affect nearly half the world's population. Despite mounting substantial T and B cell responses, humans fail to efficiently control blood-stage malaria or develop sterilizing immunity to reinfections. Although forkhead box P3 (FOXP3)+CD4+ regulatory T (Treg) cells form a part of these responses, their influence remains disputed and their mode of action is unknown. Here we show that Treg cells expand in both humans and mice in blood-stage malaria and interfere with conventional T helper cell responses and follicular T helper (TFH)-B cell interactions in germinal centers. Mechanistically, Treg cells function in a critical temporal window to impede protective immunity through cytotoxic-T-lymphocyte-associated protein-4 (CTLA-4). Targeting Treg cells or CTLA-4 in this precise window accelerated parasite clearance and generated species-transcending immunity to blood-stage malaria in mice. Our study uncovers a critical mechanism of immunosuppression associated with blood-stage malaria that delays parasite clearance and prevents development of potent adaptive immunity to reinfection. These data also reveal a temporally discrete and potentially therapeutically amenable functional role for Treg cells and CTLA-4 in limiting antimalarial immunity.
Asunto(s)
Antígeno CTLA-4/inmunología , Malaria/inmunología , Parasitemia/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Linfocitos T Reguladores/inmunología , Animales , Ensayo de Inmunoadsorción Enzimática , Citometría de Flujo , Centro Germinal/inmunología , Humanos , Tolerancia Inmunológica/inmunología , Ganglios Linfáticos/patología , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Bazo/patologíaRESUMEN
Sepsis is a systemic infection that enhances host vulnerability to secondary infections normally controlled by T cells. Using CLP sepsis model, we observed that sepsis induces apoptosis of circulating memory CD8 T-cells (TCIRCM) and diminishes their effector functions, leading to impaired CD8 T-cell mediated protection to systemic pathogen re-infection. In the context of localized re-infections, tissue resident memory CD8 T-cells (TRM) provide robust protection in a variety of infectious models. TRM rapidly 'sense' infection in non-lymphoid tissues and 'alarm' the host by enhancing immune cell recruitment to the site of the infection to accelerate pathogen clearance. Here, we show that compared to pathogen-specific TCIRCM, sepsis does not invoke significant numerical decline of Vaccinia virus induced skin-TRM keeping their effector functions (e.g., Ag-dependent IFN-γ production) intact. IFN-γ-mediated recruitment of immune cells to the site of localized infection was, however, reduced in CLP hosts despite TRM maintaining their 'sensing and alarming' functions. The capacity of memory CD8 T-cells in the septic environment to respond to inflammatory cues and arrive to the site of secondary infection/antigen exposure remained normal suggesting T-cell-extrinsic factors contributed to the observed lesion. Mechanistically, we showed that IFN-γ produced rapidly during sepsis-induced cytokine storm leads to reduced IFN-γR1 expression on vascular endothelium. As a consequence, decreased expression of adhesion molecules and/or chemokines (VCAM1 and CXCL9) on skin endothelial cells in response to TRM-derived IFN-γ was observed, leading to sub-optimal bystander-recruitment of effector cells and increased susceptibility to pathogen re-encounter. Importantly, as visualized by intravital 2-photon microscopy, exogenous administration of CXCL9/10 was sufficient to correct sepsis-induced impairments in recruitment of effector cells at the localized site of TRM antigen recognition. Thus, sepsis has the capacity to alter skin TRM anamnestic responses without directly impacting TRM number and/or function, an observation that helps to further define the immunoparalysis phase in sepsis survivors.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Memoria Inmunológica/inmunología , Sepsis/inmunología , Virus Vaccinia/inmunología , Animales , Antígenos/inmunología , Citocinas/metabolismo , Interferón gamma/biosíntesis , Piel/inmunologíaRESUMEN
Ebolaviruses are emerging pathogens that cause severe and often fatal viral hemorrhagic fevers. Four distinct ebolaviruses are known to cause Ebola virus disease in humans. The ebolavirus envelope glycoprotein (GP1,2) is heavily glycosylated, but the precise glycosylation patterns of ebolaviruses are largely unknown. Here we demonstrate that approximately 50 different N-glycan structures are present in GP1,2 derived from the four pathogenic ebolaviruses, including high mannose, hybrid, and bi-, tri-, and tetra-antennary complex glycans with and without fucose and sialic acid. The overall N-glycan composition is similar between the different ebolavirus GP1,2s. In contrast, the amount and type of O-glycan structures varies widely between ebolavirus GP1,2s. Notably, this O-glycan dissimilarity is also present between two variants of Ebola virus, the original Yambuku variant and the Makona variant responsible for the most recent Western African epidemic. The data presented here should serve as the foundation for future ebolaviral entry and immunogenicity studies.
Asunto(s)
Ebolavirus/metabolismo , Fiebre Hemorrágica Ebola/virología , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/metabolismo , Secuencias de Aminoácidos , Ebolavirus/química , Ebolavirus/clasificación , Ebolavirus/genética , Glicosilación , Humanos , Polisacáridos/metabolismo , Proteínas del Envoltorio Viral/genéticaRESUMEN
Induction of lymphopenia has been exploited therapeutically to improve immune responses to cancer therapies and vaccinations. Whereas IL-15 has well-established roles in stimulating lymphocyte responses after lymphodepletion, the mechanisms regulating these IL-15 responses are unclear. We report that cell surface IL-15 expression is upregulated during lymphopenia induced by total body irradiation (TBI), cyclophosphamide, or Thy1 Ab-mediated T cell depletion, as well as in RAG(-/-) mice; interestingly, the cellular profile of surface IL-15 expression is distinct in each model. In contrast, soluble IL-15 (sIL-15) complexes are upregulated only after TBI or αThy1 Ab. Analysis of cell-specific IL-15Rα conditional knockout mice revealed that macrophages and dendritic cells are important sources of sIL-15 complexes after TBI but provide minimal contribution in response to Thy1 Ab treatment. Unlike with TBI, induction of sIL-15 complexes by αThy1 Ab is sustained and only partially dependent on type I IFNs. The stimulator of IFN genes pathway was discovered to be a potent inducer of sIL-15 complexes and was required for optimal production of sIL-15 complexes in response to Ab-mediated T cell depletion and TBI, suggesting products of cell death drive production of sIL-15 complexes after lymphodepletion. Lastly, we provide evidence that IL-15 induced by inflammatory signals in response to lymphodepletion drives lymphocyte responses, as memory CD8 T cells proliferated in an IL-15-dependent manner. Overall, these studies demonstrate that the form in which IL-15 is expressed, its kinetics and cellular sources, and the inflammatory signals involved are differentially dictated by the manner in which lymphopenia is induced.
Asunto(s)
Interleucina-15/inmunología , Depleción Linfocítica , Linfopenia/inmunología , Animales , Modelos Animales de Enfermedad , Inflamación/inmunología , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
Immunization strategies generating large numbers of antigen-specific T cells in the female reproductive tract (FRT) can provide barrier protection against sexually-transmitted pathogens, such as the human immunodeficiency virus (HIV) and human papillomaviruses (HPV). The kinetics and mechanisms of regulation of vaccine-induced adaptive T cell-mediated immune responses in FRT are less well defined. We present here evidence for intranasal delivery of the model antigen ovalbumin (OVA) along with alpha-galactosylceramide adjuvant as a protein vaccine to induce significantly higher levels of antigen-specific effector and memory CD8⺠T cells in the FRT, relative to other systemic and mucosal tissues. Antibody blocking of the CXCR3 receptor significantly reduced antigen-specific CD8⺠T cells subsequent to intranasal delivery of the protein vaccine suggesting an important role for the CXCR3 chemokine-receptor signaling for T cell trafficking. Further, intranasal vaccination with an adenoviral vector expressing OVA or HIV-1 envelope was as effective as intramuscular vaccination for generating OVA- or ENV-specific immunity in the FRT. These results support the application of the needle-free intranasal route as a practical approach to delivering protein as well as DNA/virus vector-based vaccines for efficient induction of effector and memory T cell immunity in the FRT.
RESUMEN
The family Filoviridae contains several of the most deadly pathogens known to date and the current Ebola virus disease (EVD) outbreak in Western Africa, due to Ebola virus (EBOV) infection, highlights the need for active and broad research into filovirus pathogenesis. However, in comparison, the seven other known filovirus family members are significantly understudied. Many of these, including Marburgviruses and Ebolaviruses other than EBOV, are also highly virulent and fully capable of causing widespread epidemics. This review places the focus on these non-EBOV filoviruses, including known immunological and pathological data. The available animal models, research tools and currently available therapeutics will also be discussed along with an emphasis in the large number of current gaps in knowledge of these less highlighted filoviruses. It is evident that much research is yet to be done in order to bring the non-EBOV filovirus field to the forefront of current research and, importantly, to the development of more effective vaccines and therapeutics to combat potential future outbreaks.