RESUMEN
Checkpoint inhibitors have revolutionized cancer treatment. However, only a minority of patients respond to these immunotherapies. Here, we report that blocking the inhibitory NKG2A receptor enhances tumor immunity by promoting both natural killer (NK) and CD8+ T cell effector functions in mice and humans. Monalizumab, a humanized anti-NKG2A antibody, enhanced NK cell activity against various tumor cells and rescued CD8+ T cell function in combination with PD-x axis blockade. Monalizumab also stimulated NK cell activity against antibody-coated target cells. Interim results of a phase II trial of monalizumab plus cetuximab in previously treated squamous cell carcinoma of the head and neck showed a 31% objective response rate. Most common adverse events were fatigue (17%), pyrexia (13%), and headache (10%). NKG2A targeting with monalizumab is thus a novel checkpoint inhibitory mechanism promoting anti-tumor immunity by enhancing the activity of both T and NK cells, which may complement first-generation immunotherapies against cancer.
Asunto(s)
Antineoplásicos Inmunológicos/uso terapéutico , Carcinoma de Células Escamosas , Cetuximab/uso terapéutico , Inmunidad Celular/efectos de los fármacos , Inmunoterapia , Células Asesinas Naturales/inmunología , Subfamília C de Receptores Similares a Lectina de Células NK , Animales , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/patología , Carcinoma de Células Escamosas/inmunología , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/terapia , Ensayos Clínicos Fase II como Asunto , Humanos , Células Asesinas Naturales/patología , Ratones , Subfamília C de Receptores Similares a Lectina de Células NK/antagonistas & inhibidores , Subfamília C de Receptores Similares a Lectina de Células NK/inmunologíaRESUMEN
Although the COVID-19 pandemic peaked in March/April 2020 in France, the prevalence of infection is barely known. Using high-throughput methods, we assessed herein the serological response against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) of 1847 participants working in three sites of an institution in Paris conurbation. In May-July 2020, 11% (95% confidence interval [CI]: 9.7-12.6) of serums were positive for IgG against the SARS-CoV-2 N and S proteins, and 9.5% (95% CI: 8.2-11.0) were neutralizer in pseudo-typed virus assays. The prevalence of seroconversion was 11.6% (95% CI: 10.2-13.2) when considering positivity in at least one assay. In 5% of RT-qPCR positive individuals, no systemic IgGs were detected. Among immune individuals, 21% had been asymptomatic. Anosmia (loss of smell) and ageusia (loss of taste) occurred in 52% of the IgG-positive individuals and in 3% of the negative ones. In contrast, 30% of the anosmia-ageusia cases were seronegative, suggesting that the true prevalence of infection may have reached 16.6%. In sera obtained 4-8 weeks after the first sampling, anti-N and anti-S IgG titers and neutralization activity in pseudo-virus assay declined by 31%, 17%, and 53%, resulting thus in half-life of 35, 87, and 28 days, respectively. The population studied is representative of active workers in Paris. The short lifespan of the serological systemic responses suggests an underestimation of the true prevalence of infection.
Asunto(s)
Anticuerpos Antivirales/sangre , COVID-19/sangre , COVID-19/inmunología , Adulto , Anticuerpos Neutralizantes/sangre , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , COVID-19/epidemiología , Femenino , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Masculino , Pandemias , Paris/epidemiología , Estudios Seroepidemiológicos , Factores de TiempoRESUMEN
Some nonpathogenic bacteria were found to have protective effects in mouse models of allergic and autoimmune diseases. These "probiotics" are thought to interact with dendritic cells during Ag presentation, at the initiation of adaptive immune responses. Many other myeloid cells are the effector cells of immune responses. They are responsible for inflammation that accounts for symptoms in allergic and autoimmune diseases. We investigated in this study whether probiotics might affect allergic and autoimmune inflammation by acting at the effector phase of adaptive immune responses. The effects of one strain of Lactobacillus casei were investigated in vivo on IgE-induced passive systemic anaphylaxis and IgG-induced passive arthritis, two murine models of acute allergic and autoimmune inflammation, respectively, which bypass the induction phase of immune responses, in vitro on IgE- and IgG-induced mouse mast cell activation and ex vivo on IgE-dependent human basophil activation. L. casei protected from anaphylaxis and arthritis, and inhibited mouse mast cell and human basophil activation. Inhibition required contact between mast cells and bacteria, was reversible, and selectively affected the Lyn/Syk/linker for activation of T cells pathway induced on engagement of IgE receptors, leading to decreased MAPK activation, Ca(2+) mobilization, degranulation, and cytokine secretion. Also, adoptive anaphylaxis induced on Ag challenge in mice injected with IgE-sensitized mast cells was abrogated in mice injected with IgE-sensitized mast cells exposed to bacteria. These results demonstrate that probiotics can influence the effector phase of adaptive immunity in allergic and autoimmune diseases. They might, therefore, prevent inflammation in patients who have already synthesized specific IgE or autoantibodies.
Asunto(s)
Autoinmunidad/inmunología , Hipersensibilidad/inmunología , Inflamación/inmunología , Lacticaseibacillus casei/inmunología , Probióticos/farmacología , Inmunidad Adaptativa/efectos de los fármacos , Inmunidad Adaptativa/inmunología , Anafilaxia/inmunología , Animales , Artritis Experimental/inmunología , Basófilos/efectos de los fármacos , Basófilos/inmunología , Western Blotting , Humanos , Hipersensibilidad/prevención & control , Inmunoglobulina E/inmunología , Inflamación/prevención & control , Mastocitos/efectos de los fármacos , Mastocitos/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
TLR9 is expressed in cells of the innate immune system, as well as in B lymphocytes and their progenitors. We investigated the effect of the TLR9 ligand CpG DNA on the proliferation of pro-B cells. CpG DNA inhibits the proliferation of pro-B, but not pre-B, cells by inducing caspase-independent cell death through a pathway that requires the expression of cathepsin B. This pathway is operative in Rag-deficient mice carrying an SP6 transgene, in which B lymphopoiesis is compromised, to reduce the size of the B lymphocyte precursor compartments in the bone marrow. Thus, TLR9 signals can regulate B lymphopoiesis in vivo.
Asunto(s)
Subgrupos de Linfocitos B/citología , Subgrupos de Linfocitos B/inmunología , Catepsina B/fisiología , Diferenciación Celular/inmunología , Islas de CpG/fisiología , Células Madre/citología , Células Madre/inmunología , Animales , Subgrupos de Linfocitos B/metabolismo , Caspasas/fisiología , Catepsina B/deficiencia , Catepsina B/genética , Muerte Celular/inmunología , Diferenciación Celular/genética , Línea Celular , Proliferación Celular , Células Cultivadas , Homeostasis/inmunología , Interleucina-7/fisiología , Ligandos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Transducción de Señal/inmunología , Células Madre/metabolismo , Receptor Toll-Like 9/deficiencia , Receptor Toll-Like 9/genética , Receptor Toll-Like 9/fisiologíaRESUMEN
In type 1 diabetes, autoimmune ß-cell destruction may be favored by neoantigens harboring posttranslational modifications (PTMs) such as citrullination. We studied the recognition of native and citrullinated glucose-regulated protein (GRP)78 peptides by CD8+ T cells. Citrullination modulated T-cell recognition and, to a lesser extent, HLA-A2 binding. GRP78-reactive CD8+ T cells circulated at similar frequencies in healthy donors and donors with type 1 diabetes and preferentially recognized either native or citrullinated versions, without cross-reactivity. Rather, the preference for native GRP78 epitopes was associated with CD8+ T cells cross-reactive with bacterial mimotopes. In the pancreas, a dominant GRP78 peptide was instead preferentially recognized when citrullinated. To further clarify these recognition patterns, we considered the possibility of citrullination in the thymus. Citrullinating peptidylarginine deiminase (Padi) enzymes were expressed in murine and human medullary epithelial cells (mTECs), with citrullinated proteins detected in murine mTECs. However, Padi2 and Padi4 expression was diminished in mature mTECs from NOD mice versus C57BL/6 mice. We conclude that, on one hand, the CD8+ T cell preference for native GRP78 peptides may be shaped by cross-reactivity with bacterial mimotopes. On the other hand, PTMs may not invariably favor loss of tolerance because thymic citrullination, although impaired in NOD mice, may drive deletion of citrulline-reactive T cells.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Citrulinación/fisiología , Diabetes Mellitus Tipo 1/inmunología , Chaperón BiP del Retículo Endoplásmico/inmunología , Epítopos de Linfocito T/metabolismo , Adolescente , Adulto , Animales , Niño , Citrulinación/inmunología , Diabetes Mellitus Tipo 1/metabolismo , Chaperón BiP del Retículo Endoplásmico/química , Chaperón BiP del Retículo Endoplásmico/metabolismo , Epítopos de Linfocito T/química , Femenino , Humanos , Activación de Linfocitos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Persona de Mediana Edad , Procesamiento Proteico-Postraduccional/inmunología , Procesamiento Proteico-Postraduccional/fisiología , Adulto JovenRESUMEN
Although CD8+ T-cell-mediated autoimmune ß cell destruction occurs in type 1 diabetes (T1D), the target epitopes processed and presented by ß cells are unknown. To identify them, we combined peptidomics and transcriptomics strategies. Inflammatory cytokines increased peptide presentation in vitro, paralleling upregulation of human leukocyte antigen (HLA) class I expression. Peptide sources featured several insulin granule proteins and all known ß cell antigens, barring islet-specific glucose-6-phosphatase catalytic subunit-related protein. Preproinsulin yielded HLA-A2-restricted epitopes previously described. Secretogranin V and its mRNA splice isoform SCG5-009, proconvertase-2, urocortin-3, the insulin gene enhancer protein ISL-1, and an islet amyloid polypeptide transpeptidation product emerged as antigens processed into HLA-A2-restricted epitopes, which, as those already described, were recognized by circulating naive CD8+ T cells in T1D and healthy donors and by pancreas-infiltrating cells in T1D donors. This peptidome opens new avenues to understand antigen processing by ß cells and for the development of T cell biomarkers and tolerogenic vaccination strategies.
Asunto(s)
Presentación de Antígeno , Linfocitos T CD8-positivos/inmunología , Diabetes Mellitus Tipo 1/inmunología , Epítopos de Linfocito T/inmunología , Transcriptoma/inmunología , Animales , Biomarcadores/metabolismo , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/metabolismo , Estudios de Casos y Controles , Línea Celular , Hormona Liberadora de Corticotropina/metabolismo , Citocinas/metabolismo , Antígenos HLA/metabolismo , Humanos , Insulina/metabolismo , Polipéptido Amiloide de los Islotes Pancreáticos/metabolismo , Ratones , Proteína 7B2 Secretora Neuroendocrina/metabolismo , Proproteína Convertasa 2/metabolismo , Precursores de Proteínas/metabolismo , Proteómica/métodos , Urocortinas/metabolismoRESUMEN
The human leukocyte antigen-A2 (HLA-A2)-restricted zinc transporter 8186-194 (ZnT8186-194) and other islet epitopes elicit interferon-γ secretion by CD8+ T cells preferentially in type 1 diabetes (T1D) patients compared with controls. We show that clonal ZnT8186-194-reactive CD8+ T cells express private T cell receptors and display equivalent functional properties in T1D and healthy individuals. Ex vivo analyses further revealed that CD8+ T cells reactive to ZnT8186-194 and other islet epitopes circulate at similar frequencies and exhibit a predominantly naïve phenotype in age-matched T1D and healthy donors. Higher frequencies of ZnT8186-194-reactive CD8+ T cells with a more antigen-experienced phenotype were detected in children versus adults, irrespective of disease status. Moreover, some ZnT8186-194-reactive CD8+ T cell clonotypes were found to cross-recognize a Bacteroides stercoris mimotope. Whereas ZnT8 was poorly expressed in thymic medullary epithelial cells, variable thymic expression levels of islet antigens did not modulate the peripheral frequency of their cognate CD8+ T cells. In contrast, ZnT8186-194-reactive cells were enriched in the pancreata of T1D patients versus nondiabetic and type 2 diabetic individuals. Thus, islet-reactive CD8+ T cells circulate in most individuals but home to the pancreas preferentially in T1D patients. We conclude that the activation of this common islet-reactive T cell repertoire and progression to T1D likely require defective peripheral immunoregulation and/or a proinflammatory islet microenvironment.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Diabetes Mellitus Tipo 1/inmunología , Islotes Pancreáticos/inmunología , Páncreas/citología , Páncreas/inmunología , Adulto , Línea Celular , Niño , Femenino , Antígeno HLA-A2/inmunología , Voluntarios Sanos , Humanos , MasculinoRESUMEN
INTRODUCTION: The microbiota controls a variety of biological functions, including immunity, and alterations of the microbiota in early life are associated with a higher risk of developing allergies later in life. Several probiotic bacteria, and particularly lactic acid bacteria, were described to reduce both the induction of allergic responses and allergic manifestations. Although specific probiotic strains were used in these studies, their protective effects on allergic responses also might be common for all lactobacilli. METHODS: To determine whether allergic effector cells inhibition is a common feature of lactobacilli or whether it varies among lactobacilli strains, we compared the ability of 40 strains of the same Lactobacillus paracasei species to inhibit IgE-dependent mouse mast cell and human basophil activation. RESULTS: We uncovered a marked heterogeneity in the inhibitory properties of the 40 Lactobacillus strains tested. These segregated into three to four clusters depending on the intensity of inhibition. Some strains inhibited both mouse mast cell and human basophil activation, others strains inhibited only one cell type and another group induced no inhibition of activation for either cell type. CONCLUSIONS: Individual Lactobacillus strains of the same species differentially inhibit IgE-dependent activation of mouse mast cells and human basophils, two cell types that are critical in the onset of allergic manifestations. Although we failed to identify specific bacterial genes associated with inhibition by gene-trait matching analysis, our findings demonstrate the complexity of the interactions between the microbiota and the host. These results suggest that some L. paracasei strains might be more beneficial in allergies than others strains and provide the bases for a rational screening of lactic acid bacteria strains as next-generation probiotics in the field of allergy.
RESUMEN
With the aim of identifying genes involved in development and parasite adaptation in cestodes, four coding sequences were isolated from the cyclophyllidean Mesocestoides corti larval stage (tetrathyridium). Genes showed significant similarity to the cysteine-rich secreted protein (CRISP) encoding genes, a large family that includes stage and tissue-specific genes from diverse organisms, many associated with crucial biological processes. The full-length McCrisp2 cDNA encodes a predicted protein of 202 residues in length, containing 10 cysteines and a putative signal peptide. The expression level of McCrisp2 was estimated by Real-time PCR, relative to GAPDH, showing an increase of 75% in segmented worms compared to tetrathyridia. By in situ hybridization, McCrisp2 expression was localized mainly at the larvae apical region of tetrathyridia and in the proglottids of segmented worms. Taken together our results suggest a possible role for M. corti CRISP proteins as ES products, potentially involved in differentiation processes as proposed for homologs in other organisms.
Asunto(s)
Glicoproteínas/genética , Proteínas del Helminto/genética , Mesocestoides/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , ADN Complementario/química , Expresión Génica , Genes Homeobox , Glicoproteínas/química , Glicoproteínas/metabolismo , Proteínas del Helminto/química , Proteínas del Helminto/metabolismo , Hibridación in Situ , Mesocestoides/química , Ratones , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa/métodos , ARN de Helminto/genética , ARN Mensajero/genética , Ratas , Alineación de SecuenciaRESUMEN
Activation-induced cytidine deaminase (AID) is key to initiating somatic hypermutation (SHM) and class switch recombination (CSR), but its mode of action and regulation remains unclear. Since Pax-5 and Id-2 transcription factors play an opposing role in AID regulation, we have studied the expression of Pax-5, Id-2, and prdm-1 genes in 54 chronic lymphocytic leukemia (CLL) B cells. In 21 cases, presence of AID is constantly associated with high expression of the complete form of the Pax-5 gene (Pax-5a) and lower expression of the Id-2 and prdm-1 transcripts. In 33 cases, the absence of AID expression and CSR is associated with a reduction of Pax-5a and the appearance of a spliced form with a deletion in exon 8 (Pax-5/Delta-Ex8). Stimulation with CD40L+interleukin 4 (IL-4) induces CSR, the presence of AID transcripts, up-regulation of Pax-5a and down-regulation of Pax-5/Delta-Ex8, and Id-2 and prdm-1 transcripts. Pax-5a and Pax-5/Delta-Ex8 are translated into 2 isoforms of the B-cell-specific activator protein (BSAP) and both are able to bind the AID-promoter region. Overall, these results suggest that Pax-5/Delta-Ex8 could play an important role in the control of its own transcription and indirectly in AID expression and CSR.
Asunto(s)
Linfocitos B/inmunología , Citosina Desaminasa/inmunología , Regulación Enzimológica de la Expresión Génica/inmunología , Regulación Leucémica de la Expresión Génica/inmunología , Leucemia Linfocítica Crónica de Células B/inmunología , Factor de Transcripción PAX5/inmunología , Adulto , Anciano , Anciano de 80 o más Años , Linfocitos B/metabolismo , Linfocitos B/patología , Secuencia de Bases , Ligando de CD40 , Citidina Desaminasa , Citosina Desaminasa/metabolismo , Femenino , Humanos , Proteína 2 Inhibidora de la Diferenciación/inmunología , Proteína 2 Inhibidora de la Diferenciación/metabolismo , Leucemia Linfocítica Crónica de Células B/metabolismo , Leucemia Linfocítica Crónica de Células B/patología , Masculino , Persona de Mediana Edad , Factor de Transcripción PAX5/metabolismo , Factor 1 de Unión al Dominio 1 de Regulación Positiva , Isoformas de Proteínas/inmunología , Isoformas de Proteínas/metabolismo , Proteínas Represoras/inmunología , Proteínas Represoras/metabolismo , Eliminación de Secuencia/inmunología , Hipermutación Somática de Inmunoglobulina/inmunología , Factores de Transcripción/inmunología , Factores de Transcripción/metabolismo , Transcripción Genética/inmunología , Células Tumorales CultivadasRESUMEN
Low levels of B-cell-receptor (BCR) expression are the hallmark of tumoral B lymphocytes in B-cell chronic lymphocytic leukemia (B-CLL). These cells also respond inadequately to stimulation through the BCR. This receptor consists of a surface immunoglobulin associated with a CD79a/CD79b heterodimer. We previously showed that the intracellular synthesis of BCR components, from transcription onward, is normal. Here, we investigated the glycosylation status and cellular localization of mu, CD79a, and CD79b chains in 10 CLL patients differing in surface immunoglobulin M (IgM) expression. We reported a severe impairment of the glycosylation and folding of mu and CD79a. These defects were associated with the retention of both chains in the endoplasmic reticulum and lower levels of surface IgM expression. In contrast, no clear impairment of glycosylation and folding was observed for CD79b. No sequence defects were identified for BCR components and for the chaperone proteins involved in BCR folding processes. These data show, for the first time, that lower levels of BCR surface expression observed in CLL are accounted for by an impaired glycosylation and folding of the mu and CD79a chains.
Asunto(s)
Antígenos CD/metabolismo , Inmunoglobulina M/metabolismo , Leucemia Linfocítica Crónica de Células B/metabolismo , Leucemia Linfocítica Crónica de Células B/fisiopatología , Receptores de Antígenos de Linfocitos B/metabolismo , Anciano , Antígenos CD/química , Antígenos CD/genética , Linfocitos B/metabolismo , Linfocitos B/ultraestructura , Antígenos CD79 , Dimerización , Retículo Endoplásmico/metabolismo , Retículo Endoplásmico/ultraestructura , Femenino , Regulación Leucémica de la Expresión Génica , Glicosilación , Aparato de Golgi/metabolismo , Aparato de Golgi/ultraestructura , Humanos , Inmunoglobulina M/química , Inmunoglobulina M/genética , Masculino , Microscopía Electrónica , Persona de Mediana Edad , Chaperonas Moleculares/metabolismo , Pliegue de Proteína , Agregación de Receptores , Receptores de Antígenos de Linfocitos B/química , Receptores de Antígenos de Linfocitos B/genéticaRESUMEN
To understand the molecular processes regulating morphological changes during cestode life histories we focused on homeodomain (HD) proteins, a family of transcription factors essential for pattern formation during development. In this study we report the isolation of the partial sequence of MvLim, a LIM-HD gene of Mesocestoides corti. Other members of this gene family, characterized in Drosophila melanogaster, Caenorhabditis elegans and vertebrates contribute to cell fate determination of various neuronal subtypes. Phylogenetic analyses showed that MvLim clusters with members of the LIN-11 group and that platyhelminths have at least two different LIM-HD genes. By real time PCR we determined that MvLim expression is 20-fold greater in segmented worms than in tetrathyridia. The enhancement of MvLim expression during strobilation could be associated to changes in the innervation pattern occurring in proglottids development.