title: Tat-functionalized near-infrared emissive polymersomes for dendritic cell labeling.
abstract: Dendritic cells (DCs) play a pivotal role in both immune tolerance and the initiation of immunological responses. The ability to track DCs in vivo is imperative for the development of DC-based cellular therapies and to advance our understanding of DC function and pathophysiology. Here, we conjugate a cell permeable peptide, Tat, to near-infrared (NIR) emissive polymersomes in order to enable efficient intracellular delivery for future DC tracking with these optical probes. NIR imaging allows quantitative, repetitive, in vivo detection of fluorophore-laden cells, at centimeter tissue depths without disturbing cellular function. Flow cytometry and confocal microscopy results indicate that Tat-mediated polymersome delivery to DCs is concentration and time dependent, resulting in punctate intracellular localization. Further, loading cells with Tat NIR emissive polymersomes does not interfere with cytokine-induced DC maturation and has modest effects on DC viability, but has a significant effect on mature DC-induced activation of naive T cells. We observe significant uptake of NIR emissive polymersomes when conjugated to the peptide, with a lower detection limit of 5000 labeled DCs. The extent of polymersome delivery is estimated as 70 000 +/- 10 000 vesicles/cell, equivalent to 0.7 +/- 0.1 fmol of NIR fluorophore. Our studies will enable future in vivo tracking of ex vivo labeled DCs by NIR fluorescence based imaging.
authors.affiliation: School of Engineering and Applied Science, Department of Bioengineering, Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Natalie A
authors.initials: NA
authors.lastname: Christian
authors.forename: Michael C
authors.initials: MC
authors.lastname: Milone
authors.forename: Shraddha S
authors.initials: SS
authors.lastname: Ranka
authors.forename: Guizhi
authors.initials: G
authors.lastname: Li
authors.forename: Paul R
authors.initials: PR
authors.lastname: Frail
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Davis
authors.forename: Frank S
authors.initials: FS
authors.lastname: Bates
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Therien
authors.forename: P Peter
authors.initials: PP
authors.lastname: Ghoroghchian
authors.forename: Carl H
authors.initials: CH
authors.lastname: June
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Hammer
mesh_terms: D002470:Cell Survival; D002478:Cells, Cultured; D020285:Cryoelectron Microscopy; D003713:Dendritic Cells / Q000166:cytology / Q000378:metabolism*; D015696:Gene Products, tat / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007959:Lymphocyte Culture Test, Mixed; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D010641:Phenotype; D019265:Spectroscopy, Near-Infrared; D013997:Time Factors
chemical_list: D015696:Gene Products, tat