Targeted macrophage mannose receptor (CD206)-specific protein delivery via engineered extracellular vesicles.

Extracellular vesicles (EVs) show great potential for therapeutic delivery to human cells, with a focus on modulating immune responses. The most promising targets for inducing humoral and cellular immunity against a specific antigen are macrophages (Mϕs) and dendritic cells (DCs). Targeting mannose receptors (CD206), which are highly expressed on these antigen-presenting cells, to promote the presentation of specific antigens through EV-mediated uptake, is a promising strategy in clinical immunotherapy. Our study compares two EV-fused anti-CD206 nanobodies in delivering cargo proteins to human activated antigen-presenting cells. We demonstrated that nanobody-functionalized EVs exhibit enhanced interaction and increased uptake by CD206 cells compared to non-targeted EVs. Furthermore, replacing the full-length vesicular stomatitis virus protein G (VSV-G) with its truncated form, fused to a monoclonal anti-CD206 nanobody, significantly improves the specificity of EV uptake by CD206 cells. Our study outlines an optimized platform for the production of targeted EVs designed for specific protein delivery to CD206-positive human cells.