Development of Dendritic Cell Membrane-Coated Nanoparticles for Antigen-Specific T-Cell Engagement

Dendritic cell (DC) membrane-coated nanoparticles (DCmPs) hold significant potential for antigen-specific therapies. DCmPs carry key DC membrane proteins that facilitate DC-T cell interaction, such as the major histocompatibility complex (MHC), costimulatory CD80/86, and adhesive molecules ICAM-1. However, our current understanding of the impact of the coating processes and the composition of the final products is very limited, significantly hindering the development of DCmP-based therapy. Here, using DC2.4 cell membrane proteins and poly(lactic-<i>co</i>-glycolic acid) (PLGA) nanoparticles, we comprehensively characterized and compared the compositions and functions of DCmPs produced using sonication, extrusion, and a newly developed combined coating approach (sonication coating followed by extrusion process). The combined coating approach achieved a relatively high level of protein coating and exerted superior control over the diameter and uniformity of DCmPs relative to sonication and extrusion. We also developed a characterization strategy by leveraging the homotypic interactions between DCmPs and DC2.4 cells and determined that about 80% of PLGA particles are coated with membrane proteins, and both unbound proteins and uncoated particles are similarly present in the final products after the three coating processes. Because DC2.4 cells predominantly express MHC class I molecules, DCmPs showed preferential binding to cognate B3Z CD8+ T cells over DOBW CD4+ T cells, confirming that DCmPs bind to T cells in an antigen-specific fashion. Furthermore, we demonstrated that DCmPs can activate B3Z CD8+ T cells <i>in vitro</i>, similar to DC2.4 cells. These findings demonstrate a new coating approach that potentially improves size control over membrane-coated particles and a characterization strategy for detailed analysis of coated particle composition, which have important and broad implications for the therapeutic development of DCmPs and other membrane-coated particle technology.