RESUMO
T cells specific for SARS-CoV-2 are thought to protect against infection and development of COVID-19, but direct evidence for this is lacking. Here, we associated whole-blood-based measurement of SARS-CoV-2-specific interferon-γ-positive T cell responses with positive COVID-19 diagnostic (PCR and/or lateral flow) test results up to 6 months post-blood sampling. Amongst 148 participants donating venous blood samples, SARS-CoV-2-specific T cell response magnitude is significantly greater in those who remain protected versus those who become infected (P < 0.0001); relatively low magnitude T cell response results in a 43.2% risk of infection, whereas high magnitude reduces this risk to 5.4%. These findings are recapitulated in a further 299 participants testing a scalable capillary blood-based assay that could facilitate the acquisition of population-scale T cell immunity data (14.9% and 4.4%, respectively). Hence, measurement of SARS-CoV-2-specific T cells can prognosticate infection risk and should be assessed when monitoring individual and population immunity status.
Assuntos
COVID-19 , SARS-CoV-2 , Anticorpos Antivirais , Humanos , Interferon gama , Reação em Cadeia da Polimerase , Linfócitos TRESUMO
BACKGROUND: Patients are commonly challenged with foods containing baked milk, for example muffins, yet little is known about the specific allergen content of muffins used in milk challenges or of the effect that baking has on allergenicity. OBJECTIVE: Our objective was to compare the levels of major milk allergens in uncooked and baked muffins using monoclonal immunoassays and IgE antibody binding before and after baking. METHODS: Uncooked and baked muffins were prepared using recipes from Mount Sinai and Imperial College. Allergen levels were compared by ELISA for Bos d 5 (ß-lactoglobulin) and Bos d 11 (ß-casein). IgE reactivity was assessed using sera from milk-sensitized donors in direct binding and inhibition ELISA. RESULTS: Bos d 5 was reduced from 680 µg/g in uncooked muffin mix to 0.17 µg/g in baked muffins, representing a >99% decrease after baking. Conversely, Bos d 11 levels in baked muffin remained high and only decreased by 30% from a mean of 4249 µg/g in uncooked muffin mix to 2961 µg/g when baked (~181 mg Bos d 11 per muffin). Baked muffins retained ~70% of the IgE binding to uncooked muffin mix. Baked muffin extract inhibited IgE binding to uncooked muffin mix by up to 80%, demonstrating retention of in vitro IgE reactivity. CONCLUSIONS AND CLINICAL RELEVANCE: High levels of Bos d 11 in baked muffins pose a risk for adverse reactions, especially in patients who have high anti-casein IgE antibodies.
Assuntos
Alérgenos/imunologia , Caseínas/imunologia , Temperatura Alta , Imunoglobulina E/imunologia , Lipocalinas/imunologia , Hipersensibilidade a Leite/imunologia , Desnaturação Proteica , Culinária , Ensaio de Imunoadsorção Enzimática , HumanosRESUMO
The nature of the tumor microenvironment (TME) influences the ability of tumor-specific T cells to control tumor growth. In this study, we performed an unbiased comparison of the TME of regulatory T-cell (Treg)-replete and Treg-depleted carcinogen-induced tumors, including Treg-depleted responding (regressing) and non-responding (growing) tumors. This analysis revealed an inverse relationship between extracellular matrix (ECM) and T-cell infiltrates where responding tumors were T-cell rich and ECM poor, whereas the converse was observed in non-responder tumors. For this reason, we hypothesized that the ECM acted as a barrier to successful T-cell infiltration and tumor rejection. However, further experiments revealed that this was not the case but instead showed that an effective T-cell response dramatically altered the density of ECM in the TME. Along with loss of ECM and high numbers of infiltrating T cells, responder tumors were distinguished by the development of lymphatic and blood vessel networks with specialized immune function. ECM-rich tumors exhibited a stem cell-like gene expression profile and superior tumor-initiating capacity, whereas such features were absent in responder tumors. Overall, these findings define an extended role for an effective immune response, not just in direct killing of tumor cells but in widescale remodeling of the TME to favor loss of ECM, elimination of cancer stem cells, and propagation of adaptive immunity.
Assuntos
Neoplasias/etiologia , Células-Tronco Neoplásicas/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Microambiente Tumoral/imunologia , Animais , Linhagem Celular Tumoral , Matriz Extracelular , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Neoplasias/metabolismo , Neoplasias/patologia , Microambiente Tumoral/genéticaRESUMO
Food allergy affects up to 6% of Europeans. Allergen identification is important for the risk assessment and management of the inadvertent presence of allergens in foods. The VITAL® initiative for voluntary incidental trace allergen labeling suggests protein reference doses, based on clinical reactivity in food challenge studies, at or below which voluntary labelling is unnecessary. Here, we investigated if current analytical methodology could verify the published VITAL® 2.0 doses, that were available during this analysis, in serving sizes between 5 and 500 g. Available data on published and commercial ELISA, PCR and mass spectrometry methods, especially for the detection of peanuts, soy, hazelnut, wheat, cow's milk and hen's egg were reviewed in detail. Limit of detection, quantitative capability, matrix compatibility, and specificity were assessed. Implications by the recently published VITAL® 3.0 doses were also considered. We conclude that available analytical methods are capable of reasonably robust detection of peanut, soy, hazelnut and wheat allergens for levels at or below the VITAL® 2.0 and also 3.0 doses, with some methods even capable of achieving this in a large 500 g serving size. Cow's milk and hen's egg are more problematic, largely due to matrix/processing incompatibility. An unmet need remains for harmonized reporting units, available reference materials, and method ring-trials to enable validation and the provision of comparable measurement results.
Assuntos
Alérgenos/análise , Análise de Alimentos/normas , Hipersensibilidade Alimentar/imunologia , Alimentos/efeitos adversos , Animais , Ensaio de Imunoadsorção Enzimática , Europa (Continente) , Análise de Alimentos/métodos , Humanos , Espectrometria de MassasAssuntos
Albuminas 2S de Plantas/administração & dosagem , Antígenos de Plantas/administração & dosagem , Dessensibilização Imunológica , Glicoproteínas/administração & dosagem , Hipersensibilidade a Amendoim/imunologia , Hipersensibilidade a Amendoim/terapia , Proteínas de Plantas/administração & dosagem , Lanches , Feminino , Humanos , Masculino , Proteínas de Membrana , Hipersensibilidade a Amendoim/diagnóstico , Testes CutâneosRESUMO
T-cell infiltration into tumors represents a critical bottleneck for immune-mediated control of cancer. We previously showed that this bottleneck can be overcome by depleting immunosuppressive Foxp3+ regulatory T cells (Tregs), a process that can increase frequencies of tumor-infiltrating lymphocytes through promoting the development of specialized portals for lymphocyte entry, namely high endothelial venules (HEVs). In this paper, we used a carcinogen-induced tumor model that allows for coevolution of the tumor microenvironment and the immune response to demonstrate that Treg depletion not only results in widespread disruption to HEV networks in lymph nodes (LNs) but also activates CD8+ T cells, which then drive intratumoral HEV development. Formation of these vessels contrasts with ontogenic HEV development in LNs in that the process is dependent on the TNF receptor and independent of lymphotoxin ß receptor-mediated signaling. These intratumoral HEVs do not express the chemokine CCL21, revealing a previously undescribed intratumoral blood vessel phenotype. We propose a model where Treg depletion enables a self-amplifying loop of T-cell activation, which promotes HEV development, T-cell infiltration, and ultimately, tumor destruction. The findings point to a need to test for HEV development as part of ongoing clinical studies in patients with cancer. Cancer Immunol Res; 5(11); 1005-15. ©2017 AACR.
Assuntos
Neoplasias/imunologia , Linfócitos T Reguladores/imunologia , Animais , Células Dendríticas/imunologia , Endotélio Vascular/imunologia , Depleção Linfocítica , Linfócitos do Interstício Tumoral/imunologia , Receptor beta de Linfotoxina/imunologia , Metilcolantreno , Camundongos , Neoplasias/induzido quimicamente , Receptores do Fator de Necrose Tumoral/imunologiaRESUMO
Foxp3(+) regulatory T cells (Tregs) are often highly enriched within the tumor-infiltrating T cell pool. Using a well-characterised model of carcinogen-induced fibrosarcomas we show that the enriched tumor-infiltrating Treg population comprises largely of CXCR3(+) T-bet(+) 'TH1-like' Tregs which are thymus-derived Helios(+) cells. Whilst IL-2 maintains homeostatic ratios of Tregs in lymphoid organs, we found that the perturbation in Treg frequencies in tumors is IL-2 independent. Moreover, we show that the TH1 phenotype of tumor-infiltrating Tregs is dispensable for their ability to influence tumor progression. We did however find that unlike Tconvs, the majority of intra-tumoral Tregs express the activation markers CD69, CD25, ICOS, CD103 and CTLA4 and are significantly more proliferative than Tconvs. Moreover, we have found that CD69(+) Tregs are more suppressive than their CD69- counterparts. Collectively, these data indicate superior activation of Tregs in the tumor microenvironment, promoting their suppressive ability and selective proliferation at this site.
Assuntos
Proliferação de Células , Fibrossarcoma/metabolismo , Interleucina-2/metabolismo , Ativação Linfocitária , Linfócitos do Interstício Tumoral/metabolismo , Sarcoma Experimental/metabolismo , Proteínas com Domínio T/metabolismo , Linfócitos T Reguladores/metabolismo , Animais , Anticorpos Monoclonais/farmacologia , Biomarcadores Tumorais/imunologia , Biomarcadores Tumorais/metabolismo , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Fibrossarcoma/induzido quimicamente , Fibrossarcoma/genética , Fibrossarcoma/imunologia , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Mediadores da Inflamação/imunologia , Mediadores da Inflamação/metabolismo , Interleucina-2/antagonistas & inibidores , Interleucina-2/imunologia , Ativação Linfocitária/efeitos dos fármacos , Linfócitos do Interstício Tumoral/efeitos dos fármacos , Linfócitos do Interstício Tumoral/imunologia , Metilcolantreno , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Sarcoma Experimental/induzido quimicamente , Sarcoma Experimental/genética , Sarcoma Experimental/imunologia , Transdução de Sinais , Proteínas com Domínio T/deficiência , Proteínas com Domínio T/genética , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Células Th1/imunologia , Células Th1/metabolismo , Microambiente TumoralRESUMO
Balancing the generation of immune responses capable of controlling virus replication with those causing immunopathology is critical for the survival of the host and resolution of influenza-induced inflammation. Based on the capacity of interleukin-6 (IL-6) to govern both optimal T-cell responses and inflammatory resolution, we hypothesised that IL-6 plays an important role in maintaining this balance. Comparison of innate and adaptive immune responses in influenza-infected wild-type control and IL-6-deficient mice revealed striking differences in virus clearance, lung immunopathology and generation of heterosubtypic immunity. Mice lacking IL-6 displayed a profound defect in their ability to mount an anti-viral T-cell response. Failure to adequately control virus was further associated with an enhanced infiltration of inflammatory monocytes into the lung and an elevated production of the pro-inflammatory cytokines, IFN-α and TNF-α. These events were associated with severe lung damage, characterised by profound vascular leakage and death. Our data highlight an essential role for IL-6 in orchestrating anti-viral immunity through an ability to limit inflammation, promote protective adaptive immune responses and prevent fatal immunopathology.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Vírus da Influenza A/fisiologia , Interleucina-6/imunologia , Infecções por Orthomyxoviridae/imunologia , Pneumonia Viral/imunologia , Animais , Linfócitos T CD4-Positivos/virologia , Movimento Celular/genética , Células Cultivadas , Citocinas/metabolismo , Feminino , Mediadores da Inflamação/metabolismo , Interleucina-6/genética , Ativação Linfocitária/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infecções por Orthomyxoviridae/genética , Pneumonia Viral/genética , Pneumonia Viral/patologia , Carga Viral/genética , Replicação Viral/genéticaRESUMO
The evolution of immune blockades in tumors limits successful antitumor immunity, but the mechanisms underlying this process are not fully understood. Depletion of regulatory T cells (Treg), a T-cell subset that dampens excessive inflammatory and autoreactive responses, can allow activation of tumor-specific T cells. However, cancer immunotherapy studies have shown that a persistent failure of activated lymphocytes to infiltrate tumors remains a fundamental problem. In evaluating this issue, we found that despite an increase in T-cell activation and proliferation following Treg depletion, there was no significant association with tumor growth rate. In contrast, there was a highly significant association between low tumor growth rate and the extent of T-cell infiltration. Further analyses revealed a total concordance between low tumor growth rate, high T-cell infiltration, and the presence of high endothelial venules (HEV). HEV are blood vessels normally found in secondary lymphoid tissue where they are specialized for lymphocyte recruitment. Thus, our findings suggest that Treg depletion may promote HEV neogenesis, facilitating increased lymphocyte infiltration and destruction of the tumor tissue. These findings are important as they point to a hitherto unidentified role of Tregs, the manipulation of which may refine strategies for more effective cancer immunotherapy.
Assuntos
Quimiotaxia de Leucócito/imunologia , Linfócitos do Interstício Tumoral/imunologia , Neoplasias Experimentais/imunologia , Linfócitos T/imunologia , Vênulas/imunologia , Animais , Proliferação de Células , Endotélio Vascular/imunologia , Citometria de Fluxo , Imuno-Histoquímica , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neoplasias Experimentais/patologia , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/imunologia , Linfócitos T/citologia , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/imunologiaRESUMO
Decline of cell-mediated immunity is often attributed to decaying T-cell numbers and their distribution in peripheral organs. This study examined the hypothesis that qualitative as well as quantitative changes contribute to the declining efficacy of CD8(+) T-cell memory. Using a model of influenza virus infection, where loss of protective CD8(+) T-cell immunity was observed 6 months postinfection, we found no decline in antigen-specific T-cell numbers or migration to the site of secondary infection. There was, however, a large reduction in antigen-specific CD8(+) T-cell degranulation, cytokine secretion, and polyfunctionality. A profound loss of high-avidity T cells over time indicated that failure to confer protective immunity resulted from the inferior functional capacity of remaining low avidity cells. These data imply that high-avidity central memory T cells wane with declining antigen levels, leaving lower avidity T cells with reduced functional capabilities.
Assuntos
Alphainfluenzavirus/imunologia , Degranulação Celular/imunologia , Movimento Celular/imunologia , Imunidade Celular , Memória Imunológica , Infecções por Orthomyxoviridae/imunologia , Animais , Linfócitos T CD8-Positivos , Citocinas/imunologia , Citocinas/metabolismo , Alphainfluenzavirus/metabolismo , Camundongos , Infecções por Orthomyxoviridae/metabolismo , Fatores de TempoRESUMO
Human CD4(+) αß T cells are activated via T-cell receptor recognition of peptide epitopes presented by major histocompatibility complex (MHC) class II (MHC-II). The open ends of the MHC-II binding groove allow peptide epitopes to extend beyond a central nonamer core region at both the amino- and carboxy-terminus. We have previously found that these non-bound C-terminal residues can alter T cell activation in an MHC allele-transcending fashion, although the mechanism for this effect remained unclear. Here we show that modification of the C-terminal peptide-flanking region of an influenza hemagglutinin (HA(305-320)) epitope can alter T-cell receptor binding affinity, T-cell activation and repertoire selection of influenza-specific CD4(+) T cells expanded from peripheral blood. These data provide the first demonstration that changes in the C-terminus of the peptide-flanking region can substantially alter T-cell receptor binding affinity, and indicate a mechanism through which peptide flanking residues could influence repertoire selection.
Assuntos
Linfócitos T CD4-Positivos/citologia , Epitopos/química , Influenza Humana/imunologia , Orthomyxoviridae/metabolismo , Biotinilação , Linfócitos T CD4-Positivos/metabolismo , Citometria de Fluxo/métodos , Antígenos de Histocompatibilidade Classe II/metabolismo , Humanos , Vacinas contra Influenza/imunologia , Influenza Humana/virologia , Modelos Genéticos , Modelos Moleculares , Conformação Molecular , Peptídeos/química , Estrutura Terciária de Proteína , Ressonância de Plasmônio de Superfície , Temperatura , Fatores de TempoRESUMO
BACKGROUND: Seasonal influenza A infection affects a significant cohort of the global population annually, resulting in considerable morbidity and mortality. Therapeutic strategies are of limited efficacy, and during a pandemic outbreak would only be available to a minority of the global population. Over-the-counter medicines are routinely taken by individuals suffering from influenza, but few studies have been conducted to determine their effectiveness in reducing pulmonary immunopathology or the influence they exert upon the generation of protective immunity. METHODS: A mouse model of influenza infection was utilised to assess the efficacy of paracetamol (acetaminophen) in reducing influenza-induced pathology and to examine whether paracetamol affects generation of protective immunity. RESULTS: Administration (intraperitoneal) of paracetamol significantly decreased the infiltration of inflammatory cells into the airway spaces, reduced pulmonary immunopathology associated with acute infection and improved the overall lung function of mice, without adversely affecting the induction of virus-specific adaptive responses. Mice treated with paracetamol exhibited an ability to resist a second infection with heterologous virus comparable with that of untreated mice. CONCLUSIONS: Our results demonstrate that paracetamol dramatically reduces the morbidity associated with influenza but does not compromise the development of adaptive immune responses. Overall, these data support the utility of paracetamol for reducing the clinical symptoms associated with influenza virus infection.
Assuntos
Acetaminofen/uso terapêutico , Anti-Inflamatórios não Esteroides/uso terapêutico , Vírus da Influenza A Subtipo H1N1 , Vírus da Influenza A Subtipo H3N2 , Infecções por Orthomyxoviridae/tratamento farmacológico , Infecções Respiratórias/tratamento farmacológico , Acetaminofen/farmacologia , Imunidade Adaptativa/efeitos dos fármacos , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Celecoxib , Inibidores de Ciclo-Oxigenase 2/uso terapêutico , Dinoprostona/metabolismo , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos/métodos , Feminino , Imunidade Inata/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/fisiopatologia , Pulmão/metabolismo , Pulmão/patologia , Camundongos , Camundongos Endogâmicos C57BL , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/patologia , Infecções por Orthomyxoviridae/virologia , Pirazóis/uso terapêutico , Infecções Respiratórias/imunologia , Infecções Respiratórias/patologia , Infecções Respiratórias/virologia , Sulfonamidas/uso terapêutico , Carga Viral/efeitos dos fármacos , Eliminação de Partículas Virais/efeitos dos fármacosRESUMO
A significant enrichment of CD4(+)Foxp3(+) T cells (regulatory T cells, Treg) is frequently observed in murine and human carcinomas. As Tregs can limit effective antitumor immune responses, thereby promoting tumor progression, it is important that the mechanisms underpinning intratumoral accumulation of Tregs are identified. Because of evidence gathered mostly in vitro, the conversion of conventional T cells (Tconv) into Tregs has been proposed as one such mechanism. We assessed the contribution of conversion in vivo by analyzing the TCR (T-cell receptor) repertoires of Tconvs and Tregs in carcinogen-induced tumors in mice. Our results indicate that the TCR repertoires of Tregs and Tconvs within tumor-infiltrating lymphocytes (TIL) are largely distinct. Indeed, the cell population with the greatest degree of repertoire similarity with tumor-infiltrating Tregs was the Treg population from the tumor-draining lymph node. These findings demonstrate that conversion of Tconvs does not contribute significantly to the accumulation of tumor-infiltrating Tregs; rather, Tconvs and Tregs arise from different populations with unique TCR repertoires. Enrichment of Tregs within TILs most likely, therefore, reflects differences in the way that Tregs and Tconvs are influenced by the tumor microenvironment. Elucidating the nature of these influences may indicate how the balance between tumor-infiltrating Tregs and Tconvs can be manipulated for therapeutic purposes.