| Doctorant : |
Aline PILLOT
|
| Directeur de thèse : |
Cyrille GRANDJEAN ,
Directeur de recherche CNRS |
| Financement : |
|
| Date de la soutenance : |
lundi 26 octobre 2020, 09h30 |
| Modalité : |
- Lieu : Amphithéâtre Pasteur, bâtiment 2, campus Lombarderie
|
| Jury : |
|
Les vaccins glycoconjugués qui permettent d’obtenir une réponse protectrice dirigée contre les sucres de surface des bactéries, font partie des vaccins les plus efficaces et les plus sûrs. Les vaccins glycoconjugués sont obtenus à partir de polysaccharides purifiés ou de mimes synthétiques de ces derniers couplés à une protéine dite protéine porteuse. A l’heure actuelle, ce procédé conduit à des mélanges complexes mal caractérisés.
Des approches de mutagenèse appliquées à la protéine porteuse nous ont permis de réaliser des couplages “site-spécifiques”, permettant l’obtention de conjugués homogènes, complètement définis. Ce résultat autorise une étude fine des relations structure/immunogénicité.
Les premiers résultats semblent indiquer que la position du sucre influe à la fois sur la réponse anti-sucre et sur la réponse dirigée contre les-épitopes B de la protéine porteuse.
Lorsque le sucre est placé sur ou à proximité d’un épitope B, il semble diminuer la réponse dirigée contre la protéine porteuse. Placer le sucre au niveau d’un épitope T auxiliaire permettrait d’obtenir une réponse anti-sucre plus importante.
Les approches de mutagenèse permettent d’envisager la préparation de vaccins tripartites constitués d’une protéine porteuse sur laquelle sont couplés non seulement le sucre de surface mais aussi des molécules adjuvantes. Dans cette optique, des analogues de l’α-galactosylcéramide, un puissant activateur des lymphocytes Natural Killer invariantes ont été synthétisés.
Publications
2019
Pillot, Aline; Defontaine, Alain; Fateh, Amina; Lambert, Annie; Prasanna, Maruthi; Fanuel, Mathieu; Pipelier, Muriel; Csaba, Noemi; Violo, Typhaine; Camberlein, Emilie; Grandjean, Cyrille
Site-Specific Conjugation for Fully Controlled Glycoconjugate Vaccine Preparation Article de journal
Dans: Frontiers in Chemistry, vol. 7, no. November, p. 1–9, 2019, ISSN: 22962646.
@article{Pillot2019,
title = {Site-Specific Conjugation for Fully Controlled Glycoconjugate Vaccine Preparation},
author = {Aline Pillot and Alain Defontaine and Amina Fateh and Annie Lambert and Maruthi Prasanna and Mathieu Fanuel and Muriel Pipelier and Noemi Csaba and Typhaine Violo and Emilie Camberlein and Cyrille Grandjean},
doi = {10.3389/fchem.2019.00726},
issn = {22962646},
year = {2019},
date = {2019-01-01},
journal = {Frontiers in Chemistry},
volume = {7},
number = {November},
pages = {1--9},
abstract = {Glycoconjugate vaccines are formed by covalently link a carbohydrate antigen to a carrier protein whose role is to achieve a long lasting immune response directed against the carbohydrate antigen. The nature of the sugar antigen, its length, its ratio per carrier protein and the conjugation chemistry impact on both structure and the immune response of a glycoconjugate vaccine. In addition it has long been assumed that the sites at which the carbohydrate antigen is attached can also have an impact. These important issue can now be addressed owing to the development of novel chemoselective ligation reactions as well as techniques such as site-selective mutagenesis, glycoengineering, or extension of the genetic code. The preparation and characterization of homogeneous bivalent pneumococcal vaccines is reported. The preparation and characterization of homogeneous bivalent pneumococcal vaccines is reported. A synthetic tetrasaccharide representative of the serotype 14 capsular polysaccharide of Streptococcus pneumoniae has been linked using the thiol/maleimide coupling chemistry to four different Pneumococcal surface adhesin A (PsaA) mutants, each harboring a single cysteine mutation at a defined position. Humoral response of these 1 to 1 carbohydrate antigen/PsaA conjugates have been assessed in mice. Our results showed that the carbohydrate antigen-PsaA connectivity impacts the anti-carrier response and raise questions about the design of glycoconjugate vaccine whereby the protein plays the dual role of immunogen and carrier.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Glycoconjugate vaccines are formed by covalently link a carbohydrate antigen to a carrier protein whose role is to achieve a long lasting immune response directed against the carbohydrate antigen. The nature of the sugar antigen, its length, its ratio per carrier protein and the conjugation chemistry impact on both structure and the immune response of a glycoconjugate vaccine. In addition it has long been assumed that the sites at which the carbohydrate antigen is attached can also have an impact. These important issue can now be addressed owing to the development of novel chemoselective ligation reactions as well as techniques such as site-selective mutagenesis, glycoengineering, or extension of the genetic code. The preparation and characterization of homogeneous bivalent pneumococcal vaccines is reported. The preparation and characterization of homogeneous bivalent pneumococcal vaccines is reported. A synthetic tetrasaccharide representative of the serotype 14 capsular polysaccharide of Streptococcus pneumoniae has been linked using the thiol/maleimide coupling chemistry to four different Pneumococcal surface adhesin A (PsaA) mutants, each harboring a single cysteine mutation at a defined position. Humoral response of these 1 to 1 carbohydrate antigen/PsaA conjugates have been assessed in mice. Our results showed that the carbohydrate antigen-PsaA connectivity impacts the anti-carrier response and raise questions about the design of glycoconjugate vaccine whereby the protein plays the dual role of immunogen and carrier.