Minimal "Self" Peptides That Inhibit Phagocytic Clearance and Enhance Delivery of Nanoparticles

Abstract

Stealth Delivery Delivery of therapeutics and imaging agents is hampered by the ability of the innate immune system to recognize and clear foreign particles. "Self" cells are protected from phagocytic clearance by the membrane protein CD47 that interacts with signal regulatory protein-α (SIRPα) on macrophages. Taking advantage of this protective strategy, Rodriguez et al. (p. 971 ) labeled nanoparticles with computationally designed minimal human-CD47–based peptide (hCD47). When injected into a strain of mice in which macrophages expressed a SIRPα that cross-reacts with hCD47, the peptide prevented clearance of nanoparticles and enhanced drug delivery to tumors.