Tat-functionalized near-infrared emissive polymersomes for dendritic cell labeling.
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.
Christian
Natalie A
NA
School of Engineering and Applied Science, Department of Bioengineering, Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Milone
Michael C
MC
Ranka
Shraddha S
SS
Li
Guizhi
G
Frail
Paul R
PR
Davis
Kevin P
KP
Bates
Frank S
FS
Therien
Michael J
MJ
Ghoroghchian
P Peter
PP
June
Carl H
CH
Hammer
Daniel A
DA
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
D015696:Gene Products, tat