FORMATION ET STABILITE DES TRIPLES HELICES PURINES (ETUDES IN VITRO ET DANS LES CELLULES DE MAMMIFERES (DOCTORAT : PHARMACOLOGIE MOLECULAIRE))

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocPARIS-BIUM (751062103) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Vers l'utilisation des Immunoglobulines A humaines ou de leurs variants à des fins thérapeutiques

Parmi le nouvel ordre de médicaments représenté par les anticorps monoclonaux, la classe des immunoglobulines G occupe une place écrasante mais commence à révéler quelques limitations. Afin d'essayer de dépasser d'une façon originale ces limites, il nous est apparu judicieux de nous consacrer à une classe d'anticorps jusqu'ici peu étudiée sous l'angle d'applications thérapeutiques éventuelles : les IgA. Cette classe présente en effet des caractéristiques différentes et ainsi potentiellement complémentaires de celles des IgG. L'IgA est l'immunoglobuline la plus abondamment synthétisée dans l'organisme. Elle présente de plus un tropisme préférentiel pour les muqueuses, qui en fait un candidat médicament particulièrement intéressant pour cibler les nombreuses tumeurs à localisation muqueuse. Un autre argument plaidant pour le développement d'anticorps IgA thérapeutiques réside dans la récente mise en évidence du potentiel anti-tumoral des neutrophiles via une cytotoxicité médiée par le récepteur des IgA (FcaRI / CD89). Le travail présenté dans ce manuscrit concerne principalement l'évaluation in vitro et en phase 0 (à l'aide de modèles animaux) d'anticorps monoclonaux de classe IgA spécifiques de l'antigène CD20 (exprimé par la majorité des lymphomes B humains). Dans ce cadre, nous avons aussi étudié la fonction de divers glycanes portés par la chaîne lourde de l'IgA afin d'évaluer la possibilité de leur élimination au sein d'IgA variantes, dont la production et la caractérisation pourrait être facilitées. Ce travail identifie ainsi des modifications de la glycosylation potentiellement responsables de la formation de dépôts rénaux en cas d'administration in vivo. Il identifie aussi des variants hypoglycosylés des IgA gardant une innocuité apparente in vivo et dont les propriétés fonctionnelles sont intactes.Among the new order of drugs represented by monoclonal antibodies, IgG occupies an overwhelming land but begins to reveal some limitations. To try to overcome in an original way these limitations, we thought it wise to devote ourselves to a class of antibodies so far little studied in terms of potential therapeutic applications : IgA. IgA indeed has different characteristics and thus potentially complementary to those of IgG. IgA is the immunoglobulin most abundantly synthesized in the body. It has also a preferential tropism for mucous, making it a "candidate drug" of particular interest to target localization in many tumor mucosa. Another argument for the development of therapeutic antibodies IgA is the recent demonstration of anti-tumor potential of cytotoxicity mediated by neutrophils via the receptor for IgA (FcaRI / CD89). The work presented in this manuscript has evaluated in vitro and in "phase 0" (by using animal models) therapeutic potential of monoclonal antibody IgA specific antigen CD20 (expressed by the majority of human B lymphoma). In this context, we also studied the function of various glycans carried by the heavy chain of IgA for assess the possibility of their elimination in IgA variants and facilitated their production and characterization. This work identifies changes in IgA glycosylation potentially responsible for the formation of deposits in the kidney when administered in vivo. It also identifies variants hypoglycosylation IgA bearing an apparent safety in vivo and whose functional properties are intact.LIMOGES-BU Sciences (870852109) / SudocSudocFranceF

Long-lasting In vivo Gene Silencing by Electrotransfer of shRNA Expressing Plasmid

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Anti-CD20 IgA can protect mice against lymphoma development: evaluation of the direct impact of IgA and cytotoxic effector recruitment on CD20 target cells.

International audienceBACKGROUND: While most antibody-based therapies use IgG because of their well-known biological properties, some functional limitations of these antibodies call for the development of derivatives with other therapeutic functions. Although less abundant than IgG in serum, IgA is the most abundantly produced Ig class in humans. Besides the specific targeting of its dimeric form to mucosal areas, IgA was shown to recruit polymorphonuclear neutrophils against certain targets more efficiently than does IgG1. DESIGN AND METHODS: In this study, we investigated the various pathways by which anti-tumor effects can be mediated by anti-CD20 IgA against lymphoma cells. RESULTS: We found that polymeric human IgA was significantly more effective than human IgG1 in mediating direct killing or growth inhibition of target cells in the absence of complement. We also demonstrated that this direct killing was able to indirectly induce the classical pathway of the complement cascade although to a lesser extent than direct recruitment of complement by IgG. Recruitment of the alternative complement pathway by specific IgA was also observed. In addition to activating complement for lysis of lymphoma cell lines or primary cells from patients with lymphoma, we showed that monomeric anti-CD20 IgA can effectively protect mice against tumor development in a passive immunization strategy and we demonstrated that this protective effect may be enhanced in mice expressing the human FcαRI receptor on their neutrophils. CONCLUSIONS: We show that anti-CD20 IgA antibodies have original therapeutic properties against lymphoma cells, with strong direct effects, ability to recruit neutrophils for cell cytotoxicity and even recruitment of complement, although largely through an indirect way

Population perception of mandatory childhood vaccination programme before its implementation, France, 2017

International audienceBackgroundVaccination policy in France was previously characterised by the coexistence of eight recommended and three mandatory vaccinations for children younger than 2 years old. These 11 vaccines are now mandatory for all children born after 1 January 2018.AimTo study the French population’s opinion about this new policy and to assess factors associated with a positive opinion during this changing phase.MethodsA cross-sectional survey about vaccination was conducted from 16 November–19 December 2017 among the GrippeNet.fr cohort. Data were weighted for age, sex and education according to the French population. Univariate and multivariate analyses were performed to identify factors associated with a favourable opinion on mandatory vaccines’ extension and defined in the ‘3Cs’ model by the World Health Organization Strategic Advisory Group of Experts working group on vaccine hesitancy.ResultsOf the 3,222 participants (response rate 50.5%) and after adjustment, 64.5% agreed with the extension of mandatory vaccines. It was considered a necessary step by 68.7% of the study population, while 33.8% considered it unsafe for children and 56.9% saw it as authoritarian. Factors associated with a positive opinion about the extension of mandatory vaccines were components of the confidence, complacency and convenience dimensions of the ‘3Cs’ model.ConclusionsIn our sample, two thirds of the French population was in favour of the extension of mandatory vaccines for children. Perception of vaccine safety and benefits were major predictors for positive and negative opinions about this new policy