Dendritic Cell Membrane Vesicles for Activation and Maintenance of Antigen-Specific T Cells.

Cell membranes have recently gained attention as a promising drug delivery system. Here, dendritic cell membrane vesicles (DC-MVs) are examined as a platform to promote T cell responses. Nanosized DC-MVs are derived from DCs pretreated with monophosphoryl lipid A (MPLA), a FDA-approved immunostimulatory adjuvant. These "mature" DC-MVs activate DCs in vitro and increase their expression of costimulatory markers. DC-MVs also promote cross-priming of antigen-specific T cells in vitro, increasing their survival and CD25 expression. In addition, these mature DC-MVs potently augment the expansion of adoptively transferred CD8+ T cells in vivo, generating twofold to fourfold higher frequency of antigen-specific T cells, compared with other control formulations, including "immature" DC-MVs obtained without the MPLA pretreatment. Taken together, these results suggest that DC-MVs are an effective delivery platform for T cell activation and may serve as a potential delivery system for improving adoptive T cell therapy.