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N-glycosylation is one of the most prominent post-translational modifications (PTM) of glycoproteins. Antibodies are glycosylated proteins, and the alteration of this modification may influence its function, stability and half-life. Importantly, antibodies play a central role in humoral immunity against pathogens, particularly immunoglobulin G (IgG), which is a key effector of the humoral immune response.For this reason, the first part of this PhD work was dedicated to the development and validation of a reliable, sensitive and robust analytical method for the characterization of IgG N-glycans. To achieve this aim, procainamide was used for the labeling of the glycans. The analytical method is based on two steps: first an enrichment step using online solid phase extraction (SPE) with hydrophilic interaction liquid chromatography (HILIC) chemistry, then, a separation step using the same chemistry (HILIC) coupled to fluorescence (FLD) and mass spectrometry (MS) detectors Several parameters were optimized using an experimental design. After that, a validation process was performed, and repeatability, precision and stability were confirmed. NIST standard (reference material 8671, monoclonal antibodies), Trixuma© (biosimilar) and MabThera© (bio original) as well as commercial kits, were also used for the validation to compare our findings to the literature.After its validation, we decided to evaluate this method for the characterization of IgG N-glycans in patients with different diseases. Given the pandemic situation, the first studied disease was the COVID-19 with a group of patients suffering from severe COVID-19 and hospitalized in intensive care unit (ICU). Those patients were divided into two groups according to their clinical outcome (survival or death) and compared to healthy volunteers and ICU hospitalized patients suffering from sepsis. Our data indicated that a specific bisecting N-glycan, FA2B, is a potential biomarker of the mortality risk. The increase of F, Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie), info:eu-repo/semantics/nonPublished

The aim of this work was to obtain a proof-of-concept for the administration of monoclonal antibody- ((m)Ab) based therapeutics directly to the lungs using dry powder for inhalation formulations (DPIf) to treat asthma more efficiently than current marketed treatments. Indeed, while effective mAb treatments for asthma exist, they are all administered subcutaneously, which reduces patient comfort and compliance because of their invasiveness. Moreover, the inhalation route is currently used as the gold standard for treating pulmonary diseases and has proven to be the best choice, whenever possible, to achieve both better outcomes and fewer side effects. Furthermore, DPIf are usually more stable than liquid formulations because of a decrease in the free Gibbs energy and lower kinetics of degradation. Regarding the target, we chose the human (h) interleukin- (IL) 13 as the inflammatory mediator based on a literature review conducted at the beginning of this thesis. Indeed, as of 2014, the most promising therapeutics, besides IL-5 inhibiting treatments, were without a doubt the IL-13 inhibiting treatments with two anti-IL-13 treatments and an anti-IL-4/IL-13 dual treatment in phase III randomized clinical trial (RCT).The first part of the work was, therefore, about developing the anti-hIL-13 molecules from scratch. Two strategies were considered: (i) generating a conventional Ab antigen-binding fragment (FAB) and (ii) generating an antigen-binding fragment from atypic Camelidae immunoglobulin (Ig) G that lacks light chains, also called nanobodies (Nb). Fragments were considered rather than complete mAb because these molecules have a simpler structure, which comes with several advantages: they are easier to formulate and characterize, they require lower mass doses, and are also generally easier and cheaper to produce. Furthermore, they are much less immunogenic by nature and lack the Fc portion responsible for unwanted immune system activations. The generation of the anti, Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie), info:eu-repo/semantics/nonPublished

The Wiskott–Aldrich syndrome (WAS) is an X-linked primary immune deficiency caused by a mutation in the WAS gene. This leads to altered or absent WAS protein (WASp) expression and function resulting in thrombocytopenia, eczema, recurrent infections, and autoimmunity. In T cells, WASp is required for immune synapse formation. Patients with WAS show reduced numbers of peripheral blood T lymphocytes and an altered T-cell receptor repertoire. In vitro ,their peripheral T cells show decreased proliferation and cytokine production upon aCD3/aCD28 stimulation. It is unclear whether these T-cell defects are acquired during peripheral activation or are, in part, generated during thymic development. Here, we assessed the role of WASp during T-cell differentiation using artificial thymic organoid cultures and in the thymus of humanized mice. Although CRISPR/Cas9 WAS knockout hematopoietic stem and progenitor cells (HSPCs) rearranged the T-cell receptor and differentiated to T-cell receptor (TCR) + CD4 + CD8 + double-positive (DP) cells similar to wild-type HSPCs, a partial defect in the generation of CD8 single-positive (SP) cells was observed, suggesting that WASp is involved in their positive selection. TCR repertoire analysis of the DP and CD8 + SP population, however, showed a polyclonal repertoire with no bias toward autoreactivity. To our knowledge, this is the first study of the role of WASp in human T-cell differentiation and on TCR repertoire generation., SCOPUS: ar.j, info:eu-repo/semantics/published

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Gamma-delta (γδ) T cells are unconventional T cells that help control cytomegalovirus (CMV) infection in adults. γδ T cells develop early in gestation, and a fetal public γδ T cell receptor (TCR) clonotype is detected in congenital CMV infections. However, age-dependent γδ T cell responses to primary CMV infection are not well-understood. Flow cytometry and TCR sequencing was used to comprehensively characterize γδ T cell responses to CMV infection in a cohort of 32 infants followed prospectively from birth. Peripheral blood γδ T cell frequencies increased during infancy, and were higher among CMV-infected infants relative to uninfected. Clustering analyses revealed associations between CMV infection and activation marker expression on adaptive-like Vδ1 and Vδ3, but not innate-like Vγ9Vδ2 γδ T cell subsets. Frequencies of NKG2C+CD57+ γδ T cells were temporally associated with the quantity of CMV shed in saliva by infants with primary infection. The public γδ TCR clonotype was only detected in CMV-infected infants <120 days old and at lower frequencies than previously described in fetal infections. Our findings support the notion that CMV infection drives age-dependent expansions of specific γδ T cell populations, and provide insight for novel strategies to prevent CMV transmission and disease., SCOPUS: ar.j, info:eu-repo/semantics/published

A major γδ T cell population in human adult blood are the Vγ9Vδ2 T cells that are activated and expanded in a TCR-dependent manner by microbe-derived and endogenously derived phosphorylated prenyl metabolites (phosphoantigens). Vγ9Vδ2 T cells are also abundant in human fetal peripheral blood, but compared with their adult counterparts they have a distinct developmental origin, are hyporesponsive toward in vitro phosphoantigen exposure, and do not possess a cytotoxic effector phenotype. In order to obtain insight into the role of Vγ9Vδ2 T cells in the human fetus, we investigated their response to in utero infection with the phosphoantigen-producing parasite Toxoplasma gondii (T. gondii). Vγ9Vδ2 T cells expanded strongly when faced with congenital T. gondii infection, which was associated with differentiation toward potent cytotoxic effector cells. The Vγ9Vδ2 T cell expansion in utero resulted in a fetal footprint with public germline-encoded clonotypes in the Vγ9Vδ2 TCR repertoire 2 months after birth. Overall, our data indicate that the human fetus, from early gestation onward, possesses public Vγ9Vδ2 T cells that acquire effector functions following parasite infections., info:eu-repo/semantics/published

Malgré les progrès réalisées en matière de traitement et de diagnostic, le cancer du poumon demeure le plus répandu et le plus mortel dans le monde. La chimiothérapie conventionnelle, associant un composé de platine (cisplatine ou carboplatine) à un autre agent antinéoplasique est utilisée à quasiment tous les stades. Comme celle-ci est administrée par voie intraveineuse (IV), elle entraîne des effets secondaires systémiques importants dont certains sont dose- limitant (DLT) comme la néphrotoxicité pour le cisplatine ou la myélotoxicité pour le doublet carboplatine-paclitaxel. Par conséquent, ces agents sont administrés selon des cycles bien espacés pendant lesquels les tissus se rétablissent, et ce incluant la tumeur ;conduisant à une repopulation tumorale. En effet, une corrélation significative a été établie entre la concentration de platine dans les tumeurs pulmonaires et l’efficacité du traitement. Le but de ce travail était d’évaluer le potentiel de combiner une poudre sèche pour inhalation (CIS-DPI-50) avec le traitement de chimiothérapie IV, afin d’exposer la tumeur à l’agent cytotoxique de manière continue.La première partie de ce travail a permis de développer le CIS-DPI-50. Afin d’éviter qu’une haute concentration en cisplatine ne soit complètement solubilisée une fois dans les poumons, et afin d’assurer une exposition suffisante, il était essentiel de développer des formulations à libération contrôlée et à rétention pulmonaire suffisante. Ceci consistait en l’optimisation d’une formulation à base de microparticules lipidiques solides (CIS-DPI-TS) préalablement développée par Levet et al. Cette formulation a été reproduite afin d’évaluer son efficacité chez des souris greffées avec le modèle M109-HiFR (0.5 mg/kg, trois fois par cycle pendant deux cycles) et a démontré une survie similaire au CIS-IV (1.5 mg/kg, une fois par cycle pendant deux cycles). Cela a été effectué en (i) utilisant des excipients de grade pharmaceutique, reconnus comme sûrs (GRAS) (4, Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie), info:eu-repo/semantics/nonPublished

Thèse réalisée dans le cadre d'une collaboration avec UCB Pharma et la région Wallonne s'inscrivant dans le cadre du projet SAS. Le but de ce projet était de développer des implants sous-cutanés imprimés en trois dimensions pour permettre une libération d’anticorps thérapeutique de manière prolongée au cours du temps. En effet, les thérapies disponibles sont souvent administrées par voie intraveineuse, ce qui peut réduire la compliance des patients dû à l’inconfort et à la fréquence de ces administrations. Les systèmes de délivrance, tels que des implants, peuvent limiter les fréquences d’administration grâce à l’insertion d’un dispositif qui libèrera le principe actif au cours du temps durant une période donnée. Les implants s’inscrivent comme une alternative aux microsphères qui sont également des dispositifs développés et investigués en vue de favoriser l’adhésion et la compliance des patients. L’avènement du 3D dans le milieu pharmaceutique a montré une certaine frénésie liée au développement de la médecine personnalisée et à l’innovation du procédé dans ce secteur. La sélection d’un matériau biocompatible et biorésorbable tel que le PLGA représente une véritable plus-value dans le développement d’implant. Etant donné que ces implants sont biodégradables, le retrait n’est pas à envisager, ce qui limite les désagréments du patient à un seul acte chirurgical lors de l’implantation. Au cours de ce travail, une approche pragmatique a d’abord été abordée sur les procédés d’extrusion à chaud et de l’impression 3D en utilisant un polymère couramment employé dans l’impression grand public, le PLA. L’investigation des paramètres d’impressions (température d’impression, epaisseur de couche et vitesse d’impression) et l’usage de divers plastifiants (la triacétine (TA), le polyethylène glycol 400 (PEG 400), le citrate de triéthyle (TEC) et l’acétyle citrate de triéthyle (ATEC)) pour faciliter les procédés à chaud et dans l’idée de réduire les températures d’extrusion et d’i, Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie), info:eu-repo/semantics/nonPublished

The human fetal immune system begins to develop early during gestation; however, factors responsible for fetal immune-priming remain elusive. We explored potential exposure to microbial agents in utero and their contribution toward activation of memory T cells in fetal tissues. We profiled microbes across fetal organs using 16S rRNA gene sequencing and detected low but consistent microbial signal in fetal gut, skin, placenta, and lungs in the 2nd trimester of gestation. We identified several live bacterial strains including Staphylococcus and Lactobacillus in fetal tissues, which induced in vitro activation of memory T cells in fetal mesenteric lymph node, supporting the role of microbial exposure in fetal immune-priming. Finally, using SEM and RNA-ISH, we visualized discrete localization of bacteria-like structures and eubacterial-RNA within 14th weeks fetal gut lumen. These findings indicate selective presence of live microbes in fetal organs during the 2nd trimester of gestation and have broader implications toward the establishment of immune competency and priming before birth., SCOPUS: ar.j, info:eu-repo/semantics/published

Vγ9Vδ2 T cells are the main circulating γδ T cells in human adult blood. They are known for their T cell receptor (TCR)-dependent recognition of microbe and endogenous-derived non-peptide pyrophosphate antigens (phosphoantigens, PAg). With the intrinsically biased type 1 immune responses, Vγ9Vδ2 T cells are an important force in the defense of infections and tumors. However, the immune responses of Vγ9Vδ2 T cells in early life infections and in immunotherapies are not clear yet. In this thesis, we explored Vγ9Vδ2 T cell immune responses in both aspects. Vγ9Vδ2 T cells are abundant in human fetal peripheral blood, but compared to their adult counterparts they have a distinct developmental origin, are hyporesponsive towards in vitro phosphoantigen exposure and they do not possess a cytotoxic effector phenotype. In order to obtain insight into the role of Vγ9Vδ2 T cells in the human fetus, we investigated in the first part of this thesis their responses upon in utero infection with the phosphoantigen-producing parasite Toxoplasma gondii (T. gondii). Most congenital infections are caused by viruses, T. gondii is one of the exceptions. The organelle apicoplast present in T. gondii can generate the most potent Vγ9Vδ2 T cell activator. Thus infection in utero with T. gondii makes it a good model to observe Vγ9Vδ2 T cell immune responses in early life. By comparing to age-matched controls, we found that fetal Vγ9Vδ2 T cells were highly expanded in congenital T. gondii infected newborns, and these expanded cells were highly differentiated towards potent cytotoxic effector cells. While the impact of congenital infection on Vγ9Vδ2 T cell expansion and function waned after birth, the Vγ9Vδ2 TCR repertoire of infected infants possessed a clear fetal footprint with public clonotypes, reflecting the Vγ9Vδ2 T cell response in utero. Indeed, verification of the antigen recognition related complementarity-determining region 3 (CDR3) of the TCR for γ and δ chain by high-throughput seq, Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie), info:eu-repo/semantics/nonPublished

Human phosphoantigen-reactive Vγ9Vδ2 T cells possess several characteristics, including MHC-independent recognition of tumor cells and potent killing potential, that make them attractive candidates for cancer immunotherapeutic approaches. Injectable preparations from the hemi-parasite plant Viscum album L. (European mistletoe) are commonly prescribed as complementary cancer therapy in European countries such as Germany, but their mechanism of action remains poorly understood. Here, we investigated in-depth the in vitro response of human T cells towards mistletoe-extract drugs by analyzing their functional and T-cell-receptor (TCR) response using flow cytometry and high-throughput sequencing respectively. Non-fermented mistletoe-extract drugs (AbnobaViscum), but not their fermented counterparts (Iscador), induced specific expansion of Vγ9Vδ2 T cells among T cells. Furthermore, AbnobaViscum rapidly induced the release of cytotoxic granules and the production of the cytokines IFNγ and TNFα in Vγ9Vδ2 T cells. This stimulation of anti-cancer Vγ9Vδ2 T cells was mediated by the butyrophilin BTN3A, did not depend on the accumulation of endogenous phosphoantigens and involved the same Vγ9Vδ2 TCR repertoire as those of phosphoantigen-reactive Vγ9Vδ2 T cells. These insights highlight Vγ9Vδ2 T cells as a potential target for mistletoe-extract drugs and their role in cancer patients receiving these herbal drugs needs to be investigated., info:eu-repo/semantics/published

Vγ9Vδ2 T cells are a subset of human T lymphocytes activated by phosphoantigens in a T cell receptor-dependent manner to fight microbial invaders or kill transformed cells. Phosphoantigens are low molecular weight nonpeptidic pyrophosphate containing metabolites produced both endogenously (upregulated in transformed cells) and by microbes. Vγ9Vδ2 T cells are the first T cells generated in the foetus and have programmed functions before encountering the post-partum environment.In this PhD thesis, the aim was to assess the origin of Vγ9Vδ2 T cells in early versus adult life and to evaluate their T cell receptor repertoire and effector potential in the neonatal and infant period. First, human Vγ9Vδ2 T cells were characterised coming from foetal blood and generated by the foetal thymus and then similarities and differences with adult blood Vγ9Vδ2 T cells were identified. The data showed that there is a post-natal thymic output of Vγ9Vδ2 T cells which are different from their foetal counterparts. This finding could help guide the development of cancer immunotherapy strategies aiming to improve the resistance and tenacity of Vγ9Vδ2 T cells which enter an exhaustion state after long encounter with the antigen.Furthermore, human Vγ9Vδ2 T cells were studied early after birth regarding their T cell receptor repertoire and function. At 10 weeks after birth, Vγ9Vδ2 T cells had expanded, and a big part of the Vγ9Vδ2 T cell repertoire was foetal-derived. Additionally, Vγ9Vδ2 T cells had undergone significant functional polarisation toward potent killer effector cells. The expansion and shift in effector functions were not influenced by neonatal BCG vaccination, highlighting the role of environmental exposure upon birth. The data gathered here highlight the unique properties of this innate-like lymphocyte population which can act as a first wave of protection in early life while conventional αβ T cells are not yet optimal. Later in life, another wave of Vγ9Vδ2 T cells arrives from, Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie), info:eu-repo/semantics/nonPublished

γδ T cells are unconventional T cells that that can recognize infected and transformed cells via their γẟ TCR, thus promoting different immune responses. In addition, several studies showed that γδ T cells are important in the protection against different pathogens in early life, such as human cytomegalovirus (CMV). The diversity of the γδ TCR repertoire is mainly generated in the complementarity determining region 3 (CDR3) where V(D)J recombination takes place. One of the main players in the junctional diversity is the terminal-deoxynucleotidyl-transferase (TdT) enzyme responsible for the random template-independent nucleotide addition at the junction of the joining gene segments.In the mouse model it is established that during development, especially before birth, innate γδ T cell subsets are generated in waves and their generation depends on the type of hematopoietic stem and precursor cells (HSPC). These γδ T cells express a semi-invariant γδ TCR and can acquire a functional program already in the thymus. In human, in contrast, the idea of γδ T cells as innate-like lymphocytes is questioned by recent works showing that the γδ TCR repertoire of human pediatric thymuses and of term-delivery cord blood is highly diverse. Here, by analyzing in detail human fetal and post-natal thymi, we observed striking differences between fetal and post-natal γδ thymocytes at the γδ TCR repertoire and functional level. In contrast to post-natal γδ thymocytes, fetal γδ thymocytes were functionally programmed, expressed low levels of TdT and were highly enriched for invariant/public CMV-reactive CDR3 sequences (TRGV8-TRJP1-CATWDTTGWFKIF, TRDV2-TRDD3-CACDTGGY, and TRDV1-TRDD3-CALGELGD). The rearrangements of these invariant sequences were driven by short-homology repeats at the end of the involved gene segments, as it was observed in the mouse. In addition, we investigated the role of HSPC in the generation of this invariant γδ thymocytes by using an in vitro T cell development syste, Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie), info:eu-repo/semantics/nonPublished

γδ T cells comprise the third cell lineage of lymphocytes that use, like αβ T cells and B cells, V(D)J gene rearrangement with the potential to generate a highly diverse T cell receptor (TCR) repertoire. There is no obvious conservation of γδ T cell subsets (based on TCR repertoire and/or function) between mice and human, leading to the notion that human and mouse γδ T cells are highly different. In this review, we focus on human γδ T cells, building on recent studies using high-throughput sequencing to analyze the TCR repertoire in various settings. We make then the comparison with mouse γδ T cell subsets highlighting the similarities and differences and describe the remarkable changes during lifespan of innate and adaptive γδ T cells. Finally, we propose mechanisms contributing to the generation of innate versus adaptive γδ T cells. We conclude that key elements related to the generation of the γδ TCR repertoire and γδ T cell activation/development are conserved between human and mice, highlighting the similarities between these two species., info:eu-repo/semantics/published

In the mouse thymus, invariant γδ T cells are generated at well-defined times during development and acquire effector functions before exiting the thymus. However, whether such thymic programming and age-dependent generation of invariant γδ T cells occur in humans is not known. Here we found that, unlike postnatal γδ thymocytes, human fetal γδ thymocytes were functionally programmed (e.g. IFNγ, granzymes) and expressed low levels of terminal deoxynucleotidyl transferase (TdT). This low level of TdT resulted in a low number of N nucleotide insertions in the complementarity-determining region-3 (CDR3) of their TCR repertoire, allowing the usage of short homology repeats within the germline-encoded VDJ segments to generate invariant/public cytomegalovirus-reactive CDR3 sequences (TRGV8-TRJP1-CATWDTTGWFKIF, TRDV2-TRDD3-CACDTGGY, and TRDV1-TRDD3-CALGELGD). Furthermore, both the generation of invariant TCRs and the intrathymic acquisition of effector functions were due to an intrinsic property of fetal hematopoietic stem and precursor cells (HSPCs) caused by high expression of the RNA-binding protein Lin28b. In conclusion, our data indicate that the human fetal thymus generates, in an HSPC/Lin28b-dependent manner, invariant γδ T cells with programmed effector functions., info:eu-repo/semantics/published

Phosphoantigen-reactive Vγ9Vδ2 T cells represent the main innate human γδ T cell subset and dominate the fetal and adult peripheral blood γδ T cell repertoire. It has been hypothesized that adult blood Vγ9Vδ2 T cells find their origin in the fetus like it is established for mouse innate γδ T cells. To address this issue, we analyzed the CDR3 of the TCR of human blood and thymic Vγ9Vδ2 T cells from fetal until adult life. We first identified key differences in the CDR3 repertoire of fetal and adult blood Vγ9Vδ2 T cells, including in CDR3 features important for phosphoantigen reactivity. Next, we showed that most of these key adult CDR3 features were already present in the postnatal thymus and were further enhanced upon selection in vitro by the microbial-derived phosphoantigen (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate. Finally, we demonstrated that the generation of a fetal-type or adult-type Vγ9Vδ2 CDR3 repertoire is determined by the fetal and postnatal nature of the hematopoietic stem and precursor cell. Thus, our data indicate that fetal blood Vγ9Vδ2 T cells find their origin in the fetal thymus whereas adult blood Vγ9Vδ2 T cells are generated to a large degree independently after birth., info:eu-repo/semantics/published

Les nucléotides, en tant que seconds messagers (AMPc et GMPc) et qu’agonistes des récepteurs purinergiques (ADP, ATP, UDP et UTP) jouent de nombreux rôles dans la régulation des processus physiologiques et pathologiques. Bien que les réponses physiologiques impliquant les nucléotides ne se limitent pas aux maladies cardiovasculaires, ce projet s’est focalisé sur celles-ci, en particulier sur l’athérosclérose, le dysfonctionnement endothélial et l’anévrisme cérébral étant donné que notre laboratoire s’intéresse de près aux phénomènes inflammatoires liés à ces pathologies. Il est par exemple reconnu que les variations des taux d’AMPc et de GMPc peuvent réguler la fonction de la barrière endothéliale (via les phosphodiestérases qui les hydrolysent respectivement en AMP et GMP inactives et via les cyclases qui les synthétisent à partir des nucléotides triphosphates) et donc causer le dysfonctionnement endothélial qui est une cause sous-jacente de plusieurs conditions pathologiques telle que l’athérosclérose. Mais aussi, que le relargage de l’ATP par les fibres sympathiques dans les cellules musculaires lisses peut causer une augmentation de la pression sanguine et qu’une augmentation de l’ADP extracellulaire mène à l’agrégation plaquettaire (via les récepteurs purinergiques). Ces deux phénomènes sont associés au développement de l’athérosclérose et des anévrismes. Il est également avéré que l’ATP et l’UTP libérés par les globules rouges lors de lésions de ceux-ci permettent une vasodilatation par l’activation de la NO synthase endothéliale. L’UTP libéré peut également être métabolisé en UDP, un agoniste des récepteurs P2Y6 impliqué dans l’activation des macrophages et dans la production de NO. Suite à toutes ces implications des nucléotides dans les processus inflammatoires et le fait que la littérature n’offrait aucune méthode permettant le dosage et la séparation simultanée des neufs nucléotides étudiés dans ce travail, il semblait essentiel de développer et de valide, Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie), info:eu-repo/semantics/nonPublished