Antigen presenting ILC3 regulate T cell-dependent IgA responses to colonic mucosal-associated bacteria

Intestinal immune homeostasis is dependent upon tightly regulated and dynamic host interactions with the commensal microbiota. Immunoglobulin A (IgA) produced by mucosal B cells dictates the composition of commensal bacteria residing within the intestine. While emerging evidence suggests the majority of IgA is produced innately and may be polyreactive, mucosal-dwelling species can also elicit IgA via T cell-dependent mechanisms. However, the mechanisms that modulate the magnitude and quality of T cell-dependent IgA responses remain incompletely understood. Here we demonstrate that group 3 innate lymphoid cells (ILC3) regulate steady state interactions between T follicular helper cells (TfH) and B cells to limit mucosal IgA responses. ILC3 used conserved migratory cues to establish residence within the interfollicular regions of the intestinal draining lymph nodes, where they act to limit TfH responses and B cell class switching through antigen presentation. The absence of ILC3-intrinsic antigen presentation resulted in increased and selective IgA coating of bacteria residing within the colonic mucosa. Together these findings implicate lymph node resident, antigen-presenting ILC3 as a critical regulatory checkpoint in the generation of T cell-dependent colonic IgA and suggest ILC3 act to maintain tissue homeostasis and mutualism with the mucosal-dwelling commensal microbiota

Protection against heterologous infections by live attenuated Bordetella pertussis BPZE1

Les infections respiratoires font aujourd’hui encore partie des premières causes de morbidité et mortalité à l’échelle planétaire. De nombreux pathogènes viraux ou bactériens sont responsables de ces infections. Pour certaines d’entre elles aucun vaccin n’est disponible, comme c’est le cas du virus respiratoire syncytial, et pour d’autres les vaccins actuels souffrent d’importantes limitations. Ces limitations sont souvent liées à la variation antigénique et l’évolution constante des souches circulantes, comme dans le cas du virus de la grippe ou de Streptococcus pneumoniae. Pour d’autres, comme la coqueluche, le schéma vaccinal actuel ne permet pas de suffisamment protéger la population la plus vulnérable, càd. les enfants en bas age. La majorité des vaccins actuels sont classiquement administrés par voie parentérale. Or, la porte d’entrée des pathogènes respiratoires est la muqueuse nasale. Dès lors une immunisation intranasale semblerait plus indiquée. La vaccination intranasale présente l’avantage de cibler à la fois l’immunité locale et l’immunité systémique. D’autre part, elle ne fait pas appel à des procédures invasives et est facile à pratiquer.Dans cette optique, un nouveau vaccin vivant atténué contre la coqueluche a été développé dans le laboratoire d’accueil. Ce vaccin, appelé BPZE1, consiste en une souche génétiquement atténuée de Bordetella pertussis, l’agent étiologique de la coqueluche. Les études précliniques ont montré l’efficacité de cette souche vaccinale après une seule administration nasale. De plus, les premiers essais cliniques chez les adultes ont démontré l’innocuité et l’immunogénicité de cette souche. Au-delà de l’intérêt pour la vaccination contre la coqueluche, la souche BPZE1 présente aussi des propriétés anti-inflammatoires qui protègent contre l’asthme et contre la mortalité induite par le virus hautement pathogène de la grippe.Dans la première partie de ma thèse, nous nous sommes intéressés à étudier la protection induite par BPZE1 contre des infections hétérologues. D’abord, nous avons montré qu’une seule dose de BPZE1 protège contre une infection létale par Bordetella bronchiseptica, une bactérie appartenant au même genre que la souche vaccinale. La protection se traduit par une réduction de l’inflammation pulmonaire médiée par les cellules T régulatrices, par une augmentation significative de survie des souris infectées et une diminution de la charge bactérienne. Ensuite, nous avons étudié la protection hétérologue de BPZE1 contre une bactérie non apparentées, S. pneumoniae. Nous avons montré que l’administration intranasale de BPZE1 protège contre la mortalité induite par S. pneumoniae. Cette protection est dépendante du facteur de différenciation myéloide 88 (MyD88). Dans la deuxième partie de ma thèse, nous nous sommes intéressés à combiner cet effet anti-inflammatoire, non spécifique de BPZE1 avec l’induction d’une réponse immunitaire spécifique contre un antigène hétérologue. Ainsi, nous avons étudié la possibilité d’utiliser BPZE1 comme plateforme biotechnologique pour la présentation d’antigènes protecteurs hétérologues afin de développer des vaccins nasaux multivalents. Trois différents modèles (virus d’influenza, virus respiratoire syncytial et S. pneumoniae) ont été développés en exprimant les antigènes les mieux conservés et les plus prometteurs dans la souche BPZE1. L’ensemble de ces travaux de recherche ont montré que BPZE1 est un candidat vaccinal prometteur pour exprimer des antigènes hétérologues et protéger contre les infections respiratoires hétérologues.Respiratory infections are still among the leading causes of morbidity and mortality worldwide. Many different bacterial or viral pathogens are responsible for these infections. For some of them no vaccine is available, as is the case for the respiratory syncytial virus, and other current vaccines suffer from significant limitations. These limitations are mainly related to the antigenic variation and the constant evolution of circulating strains, as is the case of influenza virus and Streptococcus pneumoniae. For others, such as pertussis, the current vaccination programs do not result in sufficient protection of the most vulnerable population, i. e. very young infants. Most of the current vaccines are administered parenterally. However, the port of entry of respiratory pathogens is the nasal mucosa. Intranasal vaccination seems therefore more appropriate. Intranasal vaccination has the advantage of targeting both the local and the systemic immune system. In addition, it is non invasive (needle-free) and easy to apply.In this context, a new, live attenuated vaccine against pertussis has been developed in the host laboratory. The vaccine, named BPZE1, is a genetically attenuated Bordetella pertussis strain, the causative agent of whooping cough. Preclinical studies have demonstrated the efficacy of this vaccine strain after a single nasal administration. In addition, the first clinical trials in adults have demonstrated the safety and efficacy of this strain. Beyond pertussis vaccination, BPZE1 has also anti-inflammatory properties that protect against asthma and against mortality induced by highly pathogenic influenza.In the first part of my thesis, we were interested in studying the protection induced by BPZE1 against heterologous infections. Firstly, we showed that a single administration of BPZE1 conferred heterologous protection against a lethal infection with Bordetella bronchiseptica. This protection was evidenced by a reduction of lung inflammation mediated by regulatory T cells, a significant increase in survival of the challenged mice and a significant decrease in bacterial load.Then, we have investigated the heterologous protection of BPZE1 against an unrelated bacterium, S. pneumonia. We found that an intranasal administration of BPZE1 protected against mortality caused by S. pneumoniae. This protection was MyD88 dependent.In the second part of my thesis, we were interested in studying the possibility of using BPZE1 as a biotechnological platform for the presentation of heterologous protective antigens to develop multivalent vaccines. Three different models (influenza virus, respiratory syncytial virus and S. pneumoniae) were developed by expressing the most promising and conserved antigens in BPZE1.In conclusion, our data indicates that BPZE1 is a promising candidate vaccine to express foreign antigens and to protect against heterologous respiratory infections

Protection contre les infections hétérologues par la souche vaccinale atténuée Bordetella pertussis BPZE1

Les infections respiratoires font aujourd hui encore partie des premières causes de morbidité et mortalité à l échelle planétaire. De nombreux pathogènes viraux ou bactériens sont responsables de ces infections. Pour certaines d entre elles aucun vaccin n est disponible, comme c est le cas du virus respiratoire syncytial, et pour d autres les vaccins actuels souffrent d importantes limitations. Ces limitations sont souvent liées à la variation antigénique et l évolution constante des souches circulantes, comme dans le cas du virus de la grippe ou de Streptococcus pneumoniae. Pour d autres, comme la coqueluche, le schéma vaccinal actuel ne permet pas de suffisamment protéger la population la plus vulnérable, càd. les enfants en bas age. La majorité des vaccins actuels sont classiquement administrés par voie parentérale. Or, la porte d entrée des pathogènes respiratoires est la muqueuse nasale. Dès lors une immunisation intranasale semblerait plus indiquée. La vaccination intranasale présente l avantage de cibler à la fois l immunité locale et l immunité systémique. D autre part, elle ne fait pas appel à des procédures invasives et est facile à pratiquer.Dans cette optique, un nouveau vaccin vivant atténué contre la coqueluche a été développé dans le laboratoire d accueil. Ce vaccin, appelé BPZE1, consiste en une souche génétiquement atténuée de Bordetella pertussis, l agent étiologique de la coqueluche. Les études précliniques ont montré l efficacité de cette souche vaccinale après une seule administration nasale. De plus, les premiers essais cliniques chez les adultes ont démontré l innocuité et l immunogénicité de cette souche. Au-delà de l intérêt pour la vaccination contre la coqueluche, la souche BPZE1 présente aussi des propriétés anti-inflammatoires qui protègent contre l asthme et contre la mortalité induite par le virus hautement pathogène de la grippe.Dans la première partie de ma thèse, nous nous sommes intéressés à étudier la protection induite par BPZE1 contre des infections hétérologues. D abord, nous avons montré qu une seule dose de BPZE1 protège contre une infection létale par Bordetella bronchiseptica, une bactérie appartenant au même genre que la souche vaccinale. La protection se traduit par une réduction de l inflammation pulmonaire médiée par les cellules T régulatrices, par une augmentation significative de survie des souris infectées et une diminution de la charge bactérienne. Ensuite, nous avons étudié la protection hétérologue de BPZE1 contre une bactérie non apparentées, S. pneumoniae. Nous avons montré que l administration intranasale de BPZE1 protège contre la mortalité induite par S. pneumoniae. Cette protection est dépendante du facteur de différenciation myéloide 88 (MyD88). Dans la deuxième partie de ma thèse, nous nous sommes intéressés à combiner cet effet anti-inflammatoire, non spécifique de BPZE1 avec l induction d une réponse immunitaire spécifique contre un antigène hétérologue. Ainsi, nous avons étudié la possibilité d utiliser BPZE1 comme plateforme biotechnologique pour la présentation d antigènes protecteurs hétérologues afin de développer des vaccins nasaux multivalents. Trois différents modèles (virus d influenza, virus respiratoire syncytial et S. pneumoniae) ont été développés en exprimant les antigènes les mieux conservés et les plus prometteurs dans la souche BPZE1. L ensemble de ces travaux de recherche ont montré que BPZE1 est un candidat vaccinal prometteur pour exprimer des antigènes hétérologues et protéger contre les infections respiratoires hétérologues.Respiratory infections are still among the leading causes of morbidity and mortality worldwide. Many different bacterial or viral pathogens are responsible for these infections. For some of them no vaccine is available, as is the case for the respiratory syncytial virus, and other current vaccines suffer from significant limitations. These limitations are mainly related to the antigenic variation and the constant evolution of circulating strains, as is the case of influenza virus and Streptococcus pneumoniae. For others, such as pertussis, the current vaccination programs do not result in sufficient protection of the most vulnerable population, i. e. very young infants. Most of the current vaccines are administered parenterally. However, the port of entry of respiratory pathogens is the nasal mucosa. Intranasal vaccination seems therefore more appropriate. Intranasal vaccination has the advantage of targeting both the local and the systemic immune system. In addition, it is non invasive (needle-free) and easy to apply.In this context, a new, live attenuated vaccine against pertussis has been developed in the host laboratory. The vaccine, named BPZE1, is a genetically attenuated Bordetella pertussis strain, the causative agent of whooping cough. Preclinical studies have demonstrated the efficacy of this vaccine strain after a single nasal administration. In addition, the first clinical trials in adults have demonstrated the safety and efficacy of this strain. Beyond pertussis vaccination, BPZE1 has also anti-inflammatory properties that protect against asthma and against mortality induced by highly pathogenic influenza.In the first part of my thesis, we were interested in studying the protection induced by BPZE1 against heterologous infections. Firstly, we showed that a single administration of BPZE1 conferred heterologous protection against a lethal infection with Bordetella bronchiseptica. This protection was evidenced by a reduction of lung inflammation mediated by regulatory T cells, a significant increase in survival of the challenged mice and a significant decrease in bacterial load.Then, we have investigated the heterologous protection of BPZE1 against an unrelated bacterium, S. pneumonia. We found that an intranasal administration of BPZE1 protected against mortality caused by S. pneumoniae. This protection was MyD88 dependent.In the second part of my thesis, we were interested in studying the possibility of using BPZE1 as a biotechnological platform for the presentation of heterologous protective antigens to develop multivalent vaccines. Three different models (influenza virus, respiratory syncytial virus and S. pneumoniae) were developed by expressing the most promising and conserved antigens in BPZE1.In conclusion, our data indicates that BPZE1 is a promising candidate vaccine to express foreign antigens and to protect against heterologous respiratory infections.LILLE2-BU Santé-Recherche (593502101) / SudocSudocFranceF

Listeriosis, a model infection to study host-pathogen interactions in vivo

International audienceListeria monocytogenes (Lm) is a foodborne pathogen and the etiological agent of listeriosis. This facultative intracellular Gram-positive bacterium has the ability to colonize the intestinal lumen, cross the intestinal, blood-brain and placental barriers, leading to bacteremia, neurolisteriosis and maternal-fetal listeriosis. Lm is a model microorganism for the study of the interplay between a pathogenic microbe, host tissues and microbiota in vivo. Here we review how animal models permissive to Lm-host interactions allow deciphering some of the key steps of the infectious process, from the intestinal lumen to the crossing of host barriers and dissemination within the host. We also highlight recent investigations using tagged Lm and clinically relevant strains that have shed light on within-host dynamics and the purifying selection of Lm virulence factors. Studying Lm infection in vivo is a way forward to explore host biology and unveil the mechanisms that have selected its capacity to closely associate with its vertebrate hosts

Live attenuated Bordetella pertussis vaccine candidate BPZE1 transiently protects against lethal pneumococcal disease in mice

International audienceBPZE1 is a live attenuated vaccine against infection by Bordetella pertussis, the causative agent of whooping cough. It was previously shown that BPZE1 provides heterologous protection in mouse models of disease caused by unrelated pathogens, such as influenza virus and respiratory syncytial virus. Protection was also observed in mouse models of asthma and contact dermatitis. In this study, we demonstrate that BPZE1 also displays protection against an unrelated bacterial pathogen in a mouse model of invasive pneumococcal disease mediated by Streptococcus pneumoniae. While a single administration of BPZE1 provided no protection, two doses of 10 6 colonyforming units of BPZE1 given in a three-week interval protected against mortality, lung colonization and dissemination in both BALB/c and C57BL/6 mice. Unlike for the previously reported influenza challenge model, protection was short-lived, and waned within days after booster vaccination. Formaldehyde-killed BPZE1 protected only when administered following a live prime, indicating that priming requires live BPZE1 for protection. Protection against mortality was directly linked to substantially decreased bacterial dissemination in the blood and was lost in MyD88 knockout mice, demonstrating the role of the innate immune system in the mechanism of protection. This is the first report on a heterologous protective effect of the live BPZE1 vaccine candidate against an unrelated bacterial infection

Immunogenicity of live attenuated B. pertussis BPZE1 producing the universal influenza vaccine candidate M2e.

Intranasal delivery of vaccines directed against respiratory pathogens is an attractive alternative to parenteral administration. However, using this delivery route for inactivated vaccines usually requires the use of potent mucosal adjuvants, and no such adjuvant has yet been approved for human use.We have developed a live attenuated Bordetella pertussis vaccine, called BPZE1, and show here that it can be used to present the universal influenza virus epitope M2e to the mouse respiratory tract to prime for protective immunity against viral challenge. Three copies of M2e were genetically fused to the N-terminal domain of filamentous hemagglutinin (FHA) and produced in recombinant BPZE1 derivatives in the presence or absence of endogenous full-length FHA. Only in the absence of FHA intranasal administration of the recombinant BPZE1 derivative induced antibody responses to M2e and effectively primed BALB/c mice for protection against influenza virus-induced mortality and reduced the viral load after challenge. Strong M2e-specific antibody responses and protection were observed after a single nasal administration with the recombinant BPZE1 derivative, followed by a single administration of M2e linked to a virus-like particle without adjuvant, whereas priming alone with the vaccine strain did not protect.Using recombinant FHA-3M2e-producing BPZE1 derivatives for priming and the universal influenza M2e peptide linked to virus-like particles for boosting may constitute a promising approach for needle-free and adjuvant-free nasal vaccination against influenza

Differential Expression of Anti-Inflammatory RNA Binding Proteins in Lupus Nephritis

Lupus nephritis (LN) is a type of immunological complex glomerulonephritis characterized by chronic renal inflammation which is exacerbated by infiltrating leukocytes and fueled by a variety of pro-inflammatory cytokines. A profound understanding of the pathogenesis of LN is necessary to identify the optimal molecular targets. The role of RNA-binding proteins (RBPs) in post-transcriptional gene regulation in the immune system is being explored in greater depth to better understand how this regulation is implicated in inflammatory and autoimmune diseases. Tristetraprolin (TTP), Roquin-1/2, and Regnase-1 are 3 RBPs that play a critical role in the regulation of pro-inflammatory mediators by gating the degradation and/or translational silencing of target mRNAs. In this study, we proposed to focus on the differential expression of these RBPs in immune cells and renal biopsies from LN patients, as well as their regulatory impact on a specific target. Herein, we highlight a novel target of anti-inflammatory treatment by revealing the mechanisms underlying RBP expression and the interaction between RBPs and their target RNAs