Development of a flow cytometry assay which allows to evaluate the efficiency of immunomodulatory vaccines to enhance T cell-mediated antitumor response

Extracellular vesicles produced by immunomodulatory cells harboring OX40 ligand and 4-1BB ligand enhance antitumor immunity

Genetically modified tumor cells harboring immunomodulators may be used as therapeutic vaccines to stimulate antitumor immunity. The therapeutic benefit of these tumor vaccines is extensively investigated and mechanisms by which they boost antitumor response may be further explored. Tumor cells are large secretors of extracellular vesicles (EVs). These EVs are able to vehiculate RNA and proteins to target cells, and engineered EVs also vehiculate recombinant proteins. In this study, we explore immunomodulatory properties of EVs derived from antitumor vaccines expressing the TNFSF ligands 4-1BBL and OX40L, modulating immune response mediated by immune cells and eliminating tumors. Our results suggest that the EVs secreted by genetically modified tumor cells harboring TNFSF ligands can induce T cell proliferation, inhibit the transcription factor FoxP3, associated with the maintenance of Treg phenotype, and enhance antitumor activity mediated by immune cells. The immunomodulatory extracellular vesicles have potential to be further engineered for developing new approaches for cancer therapy.

Shielding and stealth effects of zwitterion moieties in double-functionalized silica nanoparticles

Surface functionalization of silica nanoparticles (SiO₂NPs) has been considered as a promising strategy to develop target-specific nanostructures. However, finding a chemical functionalization that can be used as an active targeting moiety while preserving the nanoparticles colloidal stability in biological fluids is still challenging. We present here a dual surface modification strategy for SiO₂NPs where a zwitterion (ZW) and a biologically active group (BAG) (amino, mercapto or carboxylic functionalities) are simultaneously grafted on the nanoparticles' surface. The rationale behind this strategy is to generate colloidally stable nanoparticles and avoid the nonspecific protein adsorption due to ZW groups insertion, while the effective interaction with biosystems is guaranteed by the BAGs presence. The biological efficacy was tested against VERO cells, E. coli bacteria and Zika viruses and a similar trend was observed for all tested particles. The desirable "stealth property" to prevent nonspecific protein adhesion also generated a ZW shielding effect of the BAG functionality hindering their proper interaction and activity in cells, bacteria and viruses.