The mucosal routes of immunization present several advantages compared to classical injection routes. Indeed, besides a better compliance towards patients, these routes possess their own immune system, also known as the Mucosal Associated Lymphoid Tissue (MALT), able to trigger a local mucosal response after immunization. This tissue is mainly located in the nasal and intestinal mucosa, where it is spread in small extents called Follicular Associated Epithelium (FAE). On their apical surface, the FAE contain specialized epithelial microfold cells (or M cells), whose role is to survey potential infections by sampling pathogenic fragments, and which overlay a lymphocyte and antigen presenting cells (APC) zone. Then, when an infection occurs, M cells sample and translocate antigenic fragments to CPA, which could therefore trigger lymphocyte maturation and the initiation of the subsequent immune response. This activation will lead to both humoral and cellular immunity in the infected epithelium and could also spread to distant mucosa. As many pathogens infect the body through mucosa, this way of immunization is often considered.Adjuvants are frequently added to subunit vaccines to enhance their immunogenicity toward APC. Indeed, despite their lower toxicity, they are also less immunogenic than live-attenuated vaccines. However, the administration of classical adjuvanting molecules, such as toxins or immunostimulating emulsions, via mucosal routes, has often led to serious adverse effects. Therefore, the alternative use of delivery systems to deliver antigen in APC after mucosal administration is more and more studied.Antigen delivery systems include immunomodulating particles, and inert delivery systems. The first ones can enhance the mucosal antigen bioavailability by vectorizing antigens to APC, and at the same time trigger intracellular pro-inflammatory pathways, to drive the Th1/Th2 immune balance. Among them, virus-like particles (VLP), saponin-based emulsions (ISCOMs) or MPL-containing liposomes are the most represented in clinical trials. However, their mucosal administration can lead to the same adverse effects than classical immunostimulating molecules. In parallel, true delivery systems can enhance the antigens immunogenicity by increasing their intracellular delivery, thus mimicking a natural infection. They are therefore far less toxic for the mucosa than immunomodulating particles but need to be more efficient in the mucus penetration, in the antigen association and in the APC intracellular delivery.During this thesis, we deciphered the mechanisms allowing cationic and lipidated maltodextrine nanoparticles (NPL) to deliver antigens after nasal administration.We first evaluated the ability of NPL to cross the airway mucus barrier, compared to mucopenetrant particles (PEG-coated PLGA or PLGA-PEG) and mucoadherent particles (chitosan-coated PLGA or PLGA-CS), by measuring their displacement in reconstituted mucus. We observed that in presence of the phospholipid core, the NPL were able to move in the mucus, while PLGA-CS NPs remained stuck in the gel. Moreover, we observed that the NPL uptake and the protein delivery in airway epithelial cells were not impaired by the presence of mucins, contrary to PLGA-CS that were hindered by the mucins, and to PLGA-PEG which were not taken up by the cells, due to their neutral surface charge. We finally demonstrated that the NPL mucopenetration was allowed thanks to steric and repulsive electrostatic forces between the anionic phospholipid core and the mucins.In parallel, we studied the mechanisms allowing the NPL to enhance the immunogenicity of subunit antigens after nasal administration, with a highlight on the importance of the NP’s density [...]