Development of an innovative adenovirus-inspired self-assembling vaccine platform rapidly adaptable to coronaviruses and other emergent viruses

The COVID-19 pandemic clearly shows how emergent diseases can cause severe global health and economic problems. We must be prepared to react swiftly against new pathogenic agents and this requires the development of vaccines that are safe, efficient in the long-term and easily adaptable with a short revision time. To this end, the COVID-19 mRNA and adenoviral vector vaccines have been spectacular successes, permitting rapid vaccination across the world in an unprecedented manner. Here we report the design of a new adenovirus-derived vaccine technology based on non-infectious pseudo-viral nanoparticles from the serotype 3 human adenovirus. Each nanoparticle comprises sixty identical proteins that assemble to form a 30 nm diameter spherical particle. A sequence has been engineered into the surface of this protein that enables the display of a covalently-bound target antigens. To demonstrate the efficiency of this approach, we added the SARS-CoV 2 spike protein receptor binding domain (RBD), that interacts with host cell ACE2 receptors, to the surface of the nanoparticles. We first showed that the glycosylated RBD retained its ACE2-binding function when displayed on nanoparticles. We then measured the in vivo humoral response of our vaccine candidate in mice and observed a strong antibody response after the prime injection; further levels were achieved following a second booster injection. In mice preimmunized with underivatized adenoviral nanoparticles, we tested if adenovirus seroprevalence, as frequently observed in humans, was detrimental to the RBD-mediated protection provided by our vaccine candidate. Interestingly, a strong anti-coronaviral response was still observed suggesting that existing circulating anti-adenovirus antibodies are not deleterious to our vaccine platform. We then performed pseudo-CoV 2 neutralization assays and obtained higher ID50 values than observed with COVID-19 convalescent sera, thus showing the high potential efficacy of our vaccine platform. This new vaccine technology is a tool that is easily adaptable to future SARS-CoV 2 variants and, more generally, to future emergent viruses and pathogens

Étude des mécanismes d'action de la PhotoChimiothérapie Extra-corporelle chez l'Homme

Extracorporeal Photochemotherapy (ECP) is a promising cell therapy currently used in the treatment of T cell-mediated diseases such as Cutaneous T cell lymphoma and GvHD. Conversely to immunosuppressive drugs, ECP appears to induce an immunomodulation specifically directed toward “pathogenic” T cells, without causing generalized immunosuppression. However, its mechanisms of action are not well understood. To gain further insight in these mechanisms, we first characterized the effects of ECP on Monocytes which represent a large proportion of treated cells. ECP induces a slow apoptosis of monocytes while surviving treated cells conserve their functionalities. In GvHD, we show that following ECP, “pathogenic” activated T cells undergo faster apoptosis than “normal” resting T cells. ECP induced apoptosis is immunogenic and activated-treated cells trigger dendritic cell maturation, increasing their capacity to stimulate T cells with a reduced proportion of induced-regulatory T cells. We are developing an in vitro model to identify an anti-clonotypic response which is strongly suggested by our data. Finally, in collaboration with Paediatric oncologists, we participated in the development of a pre-clinical in vitro model validating a less invasive protocol for the technique for treating paediatric GvHD patients. A clinical trial has been started to evaluate this protocol. This work represents a key step in the understanding of the mechanisms of action of ECP and contributes to an improvement of clinical practices and thus, a better patients' quality of life.La photochimiothérapie extracorporelle (PCE) est une thérapie cellulaire prometteuse utilisée avec succès dans le traitement de pathologies impliquant des lymphocytes T (LT) telles que les lymphomes T cutanés et la GvHD. Contrairement aux immunosuppresseurs, la PCE semble induire une immunomodulation dirigée spécifiquement à l'encontre des LT « pathogènes » sans immunosuppression généralisée, cependant son mode d'action reste inconnu. Afin de comprendre ces mécanismes d'action, nous avons caractérisé dans un premier temps l'effet de la PCE sur la fonctionnalité des monocytes présents en forte proportion dans l'échantillon traité. Ils entrent en apoptose lente et les cellules encore vivantes conservent leur propriétés fonctionnelles. Dans la GvHD, nous avons montré qu'après PCE, les LT « pathogènes » activés entraient plus rapidement en apoptose que les LT « normaux » au repos. L'apoptose des LT activés est immunogène et induit la maturation des cellules dendritiques, leur conférant des propriétés de stimulation T plus fortes tout en diminuant la proportion de T régulateurs induits. Nous développons un modèle in vitro afin de mettre en évidence l'induction d'une réponse anti-clonotypique fortement suggérée par nos résultats. Enfin, en collaborant avec des pédiatres oncologues, nous avons participé au développement d'un modèle in vitro pré-clinique validant un protocole allégé de la technique pour le traitement de la GvHD en pédiatrie, conduisant à l'ouverture d'un essai clinique. Nos travaux constituent une étape clé dans la compréhension des mécanismes d'action de la PCE et contribuent à l'amélioration des pratiques cliniques et ainsi de la qualité de vie des patients

Étude des mécanismes d'action de la PhotoChimiothérapie Extra-corporelle chez l'Homme

La photochimiothérapie extracorporelle (PCE) est une thérapie cellulaire prometteuse utilisée avec succès dans le traitement de pathologies impliquant des lymphocytes T (LT) telles que les lymphomes T cutanés et la GvHD. Contrairement aux immunosuppresseurs, la PCE semble induire une immunomodulation dirigée spécifiquement à l'encontre des LT pathogènes sans immunosuppression généralisée, cependant son mode d'action reste inconnu. Afin de comprendre ces mécanismes d'action, nous avons caractérisé dans un premier temps l'effet de la PCE sur la fonctionnalité des monocytes présents en forte proportion dans l'échantillon traité. Ils entrent en apoptose lente et les cellules encore vivantes conservent leur propriétés fonctionnelles. Dans la GvHD, nous avons montré qu'après PCE, les LT pathogènes activés entraient plus rapidement en apoptose que les LT normaux au repos. L'apoptose des LT activés est immunogène et induit la maturation des cellules dendritiques, leur conférant des propriétés de stimulation T plus fortes tout en diminuant la proportion de T régulateurs induits. Nous développons un modèle in vitro afin de mettre en évidence l'induction d'une réponse anti-clonotypique fortement suggérée par nos résultats. Enfin, en collaborant avec des pédiatres oncologues, nous avons participé au développement d'un modèle in vitro pré-clinique validant un protocole allégé de la technique pour le traitement de la GvHD en pédiatrie, conduisant à l'ouverture d'un essai clinique. Nos travaux constituent une étape clé dans la compréhension des mécanismes d'action de la PCE et contribuent à l'amélioration des pratiques cliniques et ainsi de la qualité de vie des patients.Extracorporeal Photochemotherapy (ECP) is a promising cell therapy currently used in the treatment of T cell-mediated diseases such as Cutaneous T cell lymphoma and GvHD. Conversely to immunosuppressive drugs, ECP appears to induce an immunomodulation specifically directed toward pathogenic T cells, without causing generalized immunosuppression. However, its mechanisms of action are not well understood. To gain further insight in these mechanisms, we first characterized the effects of ECP on Monocytes which represent a large proportion of treated cells. ECP induces a slow apoptosis of monocytes while surviving treated cells conserve their functionalities. In GvHD, we show that following ECP, pathogenic activated T cells undergo faster apoptosis than normal resting T cells. ECP induced apoptosis is immunogenic and activated-treated cells trigger dendritic cell maturation, increasing their capacity to stimulate T cells with a reduced proportion of induced-regulatory T cells. We are developing an in vitro model to identify an anti-clonotypic response which is strongly suggested by our data. Finally, in collaboration with Paediatric oncologists, we participated in the development of a pre-clinical in vitro model validating a less invasive protocol for the technique for treating paediatric GvHD patients. A clinical trial has been started to evaluate this protocol. This work represents a key step in the understanding of the mechanisms of action of ECP and contributes to an improvement of clinical practices and thus, a better patients' quality of life.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Immune Checkpoint Inhibitor Rechallenge and Resumption: a systematic review

Purpose of the review: The reintroduction of immune checkpoint inhibitors (ICIs) after disease progression (rechallenge) or immune-related adverse events (irAEs) recovering (resumption) raises questions in terms of efficacy and safety. Recent findings: Here, we reviewed literature data about ICIs rechallenge/resumption in cancer patients along with their clinical characteristics to explore those factors associated with better outcomes. Summary: Heterogenous results were pointed out across rechallenge studies with an overall response rate between 0% and 54%, a progression free survival ranged from 1,5 and 12,9 months and an overall survival between 6,5 and 23,8 months. Better outcomes have been recorded in patients with good ECOG PS, longer duration of initial ICI, discontinuation reason of initial ICI other than progression and those who received ICI sequence other than the switch between anti-PD1 and anti-PDL1. Studies about ICI resumption highlighted that certain types of irAEs were more likely to relapse at retreatment. These results suggest that ICI rechallenge / resumption can be an interesting strategy for selected patients

Leveraging a powerful allogeneic dendritic cell line towards neoantigen-based cancer vaccines

In recent years, immunotherapy has finally found its place in the anti-cancer therapeutic arsenal, even becoming standard of care as first line treatment for metastatic forms. The clinical benefit provided by checkpoint blockers such as anti-PD-1/PD-L1 in many cancers revolutionized the field. However, too many patients remain refractory to these treatments due to weak baseline anti-cancer immunity. There is therefore a need to boost the frequency and function of patients' cytotoxic CD8+ cellular effectors by targeting immunogenic and tumor-restricted antigens, such as neoantigens using an efficient vaccination platform. Dendritic cells (DC) are the most powerful immune cell subset for triggering cellular immune response. However, autologous DC-based vaccines display several limitations, such as the lack of reproducibility and the limited number of cells that can be manufactured. Here we discuss the advantages of a new therapeutic vaccine based on an allogeneic Plasmacytoid DC cell line, which is easy to produce and represents a powerful platform for priming and expanding anti-neoantigen cytotoxic CD8+ T cells

Inulin Prebiotic Protects against Lethal Pseudomonas aeruginosa Acute Infection via γδ T Cell Activation

Pseudomonas aeruginosa (P. aeruginosa) causes harmful lung infections, especially in immunocompromised patients. The immune system and Interleukin (IL)-17-producing γδ T cells (γδ T) are critical in controlling these infections in mice. The gut microbiota modulates host immunity in both cancer and infection contexts. Nutritional intervention is a powerful means of modulating both microbiota composition and functions, and subsequently the host's immune status. We have recently shown that inulin prebiotic supplementation triggers systemic γδ T activation in a cancer context. We hypothesized that prophylactic supplementation with inulin might protect mice from lethal P. aeruginosa acute lung infection in a γδ T-dependent manner. C57Bl/6 mice were supplemented with inulin for 15 days before the lethal P. aeruginosa lung infection, administered intranasally. We demonstrate that prophylactic inulin supplementation triggers a higher proportion of γδ T in the blood, accompanied by a higher infiltration of IL-17-producing γδ T within the lungs, and protects 33% of infected mice from death. This observation relies on γδ T, as in vivo γδ TcR blocking using a monoclonal antibody completely abrogates inulin-mediated protection. Overall, our data indicate that inulin supplementation triggers systemic γδ T activation, and could help resolve lung P. aeruginosa infections. Moreover, our data suggest that nutritional intervention might be a powerful way to prevent/reduce infection-related mortality, by reinforcing the microbiota-dependent immune system

La photochimiothérapie extracorporelle ou l’immunothérapie par cellules modifiées par photochimie

International audienceExtracorporeal photochemotherapy (ECP) is an autologous cell therapy used for the treatment of diseases involving pathogenic cells: cutaneous T-cell lymphoma, organ rejection and graft versus host disease. During an ECP procedure, patients receive a cellular product consisting of autologous mononuclear cells, containing the pathogenic cells, treated with a photosensitising agent and an UV-A radiation. The aim of the treatment is to induce a specific immune reaction modulating the activity of untreated pathogenic lymphocytes responsible for the disease and therefore an improvement of clinical manifestations. The precise mechanisms of action remain to be defined in humans. Its efficacy coupled with the absence of side effects could lead to decrease the use of immunosuppressive drugs. PCE appears as an immunotherapy using cells modified by photochemistry, which allows specific immune modulation of pathogenic lymphocytes.La photochimiothérapie extracorporelle (PCE) est une technique de thérapie cellulaire autologue utilisée dans le traitement de pathologies impliquant des lymphocytes pathogènes : lymphomes cutanés à cellules T, rejet d'organe et maladie du greffon contre l'hôte. À chaque séance de PCE, les patients reçoivent un produit cellulaire composé de cellules mononucléées autologues, contenant les cellules pathogènes, traitées par un agent photosensibilisant et un rayonnement UV-A. L'objectif du traitement est d'entraîner une réaction spécifique du système immunitaire modulant l'activité des lymphocytes pathogènes non traités responsables de la pathologie et par conséquent une amélioration des signes cliniques. Les mécanismes d'action précis restent cependant à identifier chez l'homme. Son efficacité associée à l'absence d'effets secondaires peut conduire à diminuer le recours aux immunosuppresseurs. La PCE apparaît donc comme une immunothérapie par cellules modifiées par photochimie qui permet une immunomodulation spécifique de lymphocytes pathogènes

Argumentaire pour une utilisation plus large de la photochimiothérapie extracorporelle chez l’enfant

International audienceThe management of immune diseases in children remains challenging , although significant advances have been made. In addition to pharmacological approaches, extracorporeal photochemotherapy (ECP) is distinctive in its ability to provide immunomodulation without immune suppression or toxicity. However, in practice, this therapy is not widely used because of logistical issues and the lack of robust clinical pediatric studies. Here, we discuss the potential clinical applications of ECP in children and emphasize the need for a rigorous and specifically pediatric clinical evaluation of ECP. ß 2010 Elsevier Masson SAS. All rights reserved. Résumé Malgré l'apport des biothérapies, le traitement des maladies dysim-munitaires sévères et des conflits allogéniques de l'enfant reste difficile et entaché de nombreuses complications. Dans ce contexte, la photo-chimiothérapie extracorporelle (PCE) (thérapie cellulaire qui repose sur l'effet immunomodulateur des cellules mononucléées du patient, prélevées par aphérèse et exposées ex vivo aux rayons ultraviolets A [UVA] en présence de psoralène) a l'avantage notable d'induire une tolérance immunitaire sans générer d'immunosuppression systémique ni de toxicité a ` court, moyen ou long terme. Cette immunomodulation fait intervenir notamment la génération de lymphocytes T régulateurs (T reg). Malgré cela, la PCE est peu utilisée en raison de ses contraintes logistiques et du manque de données cliniques. Nous proposons une revue des indications reconnues et potentielles de la PCE en pédiatrie. Nous insistons sur la nécessité d'une e ´valuation clinique spécifique a ` l'enfant qui ne peut se concevoir sans la participation active des cliniciens pédiatres en particulier dans le domaine de la transplanta-tion et des maladies auto-immunes et inflammatoires