Particulate antigens administrated by intranasal and intravaginal routes in a prime-boost strategy improve HIV-specific T generation, high-quality antibodies and long-lasting mucosal immunity.

Mucosal surfaces serve as the primary entry points for pathogens such as SARS- CoV-2 coronavirus or HIV in the human body. Mucosal vaccination plays a crucial role to successfully induce long-lasting systemic and local immune responses to confer sterilizing immunity. However, antigen formulations and delivery methods must be properly selected since they are decisive for the quality and the magnitude of the elicited immune responses in mucosa.

Retrovirus-Based Virus-Like Particle Immunogenicity and Its Modulation by Toll-Like Receptor Activation.

Retrovirus-derived virus-like particles (VLPs) are particularly interesting vaccine platforms, as they trigger efficient humoral and cellular immune responses and can be used to display heterologous antigens. In this study, we characterized the intrinsic immunogenicity of VLPs and investigated their possible adjuvantization by incorporation of Toll-like receptor (TLR) ligands. We designed a noncoding single-stranded RNA (ncRNA) that could be encapsidated by VLPs and induce TLR7/8 signaling.

Low-Dose IL-2 Induces Regulatory T Cell-Mediated Control of Experimental Food Allergy.

Regulatory T cells (Tregs) are pivotal for maintenance of immune self-tolerance and also regulate immune responses to exogenous Ags, including allergens. Both decreased Treg number and function have been reported in allergic patients, offering new therapeutic perspectives. We previously demonstrated that Tregs can be selectively expanded and activated by low doses of IL-2 (ld-IL-2) inducing immunoregulation without immunosuppression and established its protective effect in autoimmune diseases.

Different immunogenicity but similar antitumor efficacy of two DNA vaccines coding for an antigen secreted in different membrane vesicle-associated forms.

The induction of an active immune response to control or eliminate tumours is still an unfulfilled challenge. We focused on plasmid DNA vaccines using an innovative approach whereby the antigen is expressed in association with extracellular vesicles (EVs) to facilitate antigen cross-presentation and improve induced immunity. Our two groups had independently shown previously that DNA vaccines encoding EV-associated antigens are more efficient at inducing cytotoxic T-cell responses than vaccines encoding the non-EV-associated antigen.

Analysis of ESCRT functions in exosome biogenesis, composition and secretion highlights the heterogeneity of extracellular vesicles.

Exosomes are extracellular vesicles (EVs) secreted upon fusion of endosomal multivesicular bodies (MVBs) with the plasma membrane. The mechanisms involved in their biogenesis have not yet been fully identified although they could be used to modulate exosome formation and therefore are a promising tool in understanding exosome functions. We have performed an RNA interference screen targeting 23 components of the endosomal sorting complex required for transport (ESCRT) machinery and associated proteins in MHC class II (MHC II)-expressing HeLa-CIITA cells.

HLA-G inhibition of NK-cell cytolytic function is uncoupled from tumor cell lipid raft reorganization.

HLA-G is a non-classical HLA class I molecule with tolerogenic properties and restricted tissue distribution. The expression of HLA-G can be induced by tumors thus providing an efficient way to escape the anti-tumoral immune response. Although lipid rafts regulate diverse immunological mechanisms their relationship with HLA-G remains controversial.