Fig. 2. Targeting immune cells by particle-based therapeutics.

a | Tissue-resident immune cells, such as macrophages, dendritic cells, memory T cells and B cells, are directly targeted through local tissue immunomodulation. Particle administration can passively reprogram inflammatory cells for immunosuppressive purposes. b | Polymeric particles are designed with ligands or antibodies that target leukocyte adhesion molecules overexpressed in inflamed vasculature. The ligand-mediated anchoring of particles to the endothelium permits accumulation of drug carriers to pathological areas, halting inflammation. Targeted particles can also competitively block binding sites used in immune cell migration, preventing immune cell accumulation at sites of inflammation. c | Polymeric particles can divert or reroute circulating blood-resident cells, such as neutrophils and monocytes, from inflammation sites through particle–cell association and cell phenotypic changes after particle uptake. WBC, white blood cell.