PLGA Microspheres Coated with Cancer Cell-Derived Vesicles for Improved Internalization into Antigen-Presenting Cells and Immune Stimulation

Microspheres (MS; 1-3 mu m) with different degrees of surface roughness were prepared to assess the effects of surface topology on internalization into antigen-presenting cells (APCs; macrophages and dendritic cells). In this study, we demonstrated that the intracellular uptake of MS is readily enhanced by surface modification with nanoparticles or cancer cell derived vesicles (VE) to modulate their surface topology. MS coated with nanovesicles (MS-VE) with high surface roughness was more successfully and efficiently engulfed by APCs, compared with bare MS and those with low surface roughness. Incorporated MPLA within MS-VEs (M/MS-VE) triggered greatly elevated release of immune stimulating cytokines, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), from macrophages and dendritic cells, compared to free MPLA. Taken together, this MS-VE could serve as a platform system for the delivery of immune stimulators and antigens to APCs with negligible toxicity.