Biodegradable polymer, PLGA, is an efficient vehicle for class II MHC-restricted antigen presentation and the induction of DC maturation

Abstract The antigen presentation and maturation activities of antigen-encapsulated biodegradable nanoparticles were compared with that of antigen-antibody immune complexes. Dendritic cells (DCs) were allowed to uptake ovalbumin (OVA) via pinocytosis, phagocytosis or endocytosis, and then the levels of MHC-restricted OVA peptide presentation were measured using OVA specific CD4 and CD8 T cells. Poly(D,L-lactic acid-co-glycolic acid, PLGA)-encapsulated OVA (pOVA) and OVA-IgG complexes (OVA-IC) were equally efficient in inducing MHC class I and II-restricted OVA peptide presentation. Comparison of the amount of OVA peptide presentation showed that class II-restricted presentation pathways were robust process compared to class I-restricted presentation pathways. Maturation inducing activities of pOVA and OVA-IC were also examined. pOVA was as efficient as or better compared to OVA-IC in inducing the expression of cell surface molecules such as class II, CD80, CD86, and the secretion of cytokines IL-6, IL-1β and TNF-α. These results show that the biodegradable polymer, PLGA, is an efficient vehicle not only for class II-restricted antigen presentation but also for induction of DC maturation. The present study also shows that in exogenous antigen presentation by DCs, cross presentation is a much weaker phenomenon compared to MHC class II-restricted presentation.