Development of new polymer-based particulate systems for anti-glioma vaccination

Biodegradable and biocompatible microspheres represent a promising alternative to conventional adjuvants for anti-tumour vaccination. Focusing on glioma, we developed two poly(d,l-lactide-co-glycolide) (PLGA)-based particulate systems presenting tumour antigens associated with plasma membranes or with cell lysates. Glioma cell fractions were prepared for adsorption onto poly-d-lysine (PDL)-coated PLGA microspheres formulated using a double-emulsion procedure. Adsorption was followed by 125I-radiolabelling, Western blot and confocal laser scanning microscopy. Only a panel (34%) of the proteins isolated from both cell fractions adsorbed onto PDL-coated PLGA microspheres. The integrity of the epitopes after loading was preserved, as shown by identification of plasma membrane and cytoplasmic markers. Finally, one of the major potential advantages of those particulate systems resides in the fact they not only serve as injectable adjuvant matrices presenting tumour antigens to antigen presenting cells, but also as potential reservoirs for controlled delivery of active immunostimulant molecules.