title: Nanoparticle clearance is governed by Th1/Th2 immunity and strain background.
abstract: Extended circulation of nanoparticles in blood is essential for most clinical applications. Nanoparticles are rapidly cleared by cells of the mononuclear phagocyte system (MPS). Approaches such as grafting polyethylene glycol onto particles (PEGylation) extend circulation times; however, these particles are still cleared, and the processes involved in this clearance remain poorly understood. Here, we present an intravital microscopy-based assay for the quantification of nanoparticle clearance, allowing us to determine the effect of mouse strain and immune system function on particle clearance. We demonstrate that mouse strains that are prone to Th1 immune responses clear nanoparticles at a slower rate than Th2-prone mice. Using depletion strategies, we show that both granulocytes and macrophages participate in the enhanced clearance observed in Th2-prone mice. Macrophages isolated from Th1 strains took up fewer particles in vitro than macrophages from Th2 strains. Treating macrophages from Th1 strains with cytokines to differentiate them into M2 macrophages increased the amount of particle uptake. Conversely, treating macrophages from Th2 strains with cytokines to differentiate them into M1 macrophages decreased their particle uptake. Moreover, these results were confirmed in human monocyte-derived macrophages, suggesting that global immune regulation has a significant impact on nanoparticle clearance in humans.
authors.affiliation: Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA.
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Jones
authors.forename: Reid A
authors.initials: RA
authors.lastname: Roberts
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Robbins
authors.forename: Jillian L
authors.initials: JL
authors.lastname: Perry
authors.forename: Marc P
authors.initials: MP
authors.lastname: Kai
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.forename: Tao
authors.initials: T
authors.lastname: Bo
authors.forename: Mary E
authors.initials: ME
authors.lastname: Napier
authors.forename: Jenny P Y
authors.initials: JP
authors.lastname: Ting
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Desimone
authors.forename: James E
authors.initials: JE
authors.lastname: Bear
mesh_terms: D000818:Animals; D019540:Area Under Curve; D004337:Drug Carriers / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008856:Microscopy, Fluorescence; D053758:Nanoparticles; D013045:Species Specificity; D018417:Th1 Cells / Q000276:immunology* / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism
chemical_list: D004337:Drug Carriers