title: Mannosylated polyion complexes for in vivo gene delivery into CD11c(+) dendritic cells.
abstract: Dendritic cells (DCs) possess unique abilities in initiating primary immune responses and thus represent prime targets for DNA-based vaccinations. Here, we describe the design and synthesis of mannosylated polyion complexes (PICs) composed of cationic polyethylenimine (PEI) and hydrophilic polyethylene glycol (PEG) segments, and bearing mono- and trivalent mannose as a ligand for targeting mannose receptor (MR/CD206)-positive DCs. Amino-terminated mannose (Man)-containing ligands in mono- and trivalent presentations (Man- and Man3-, respectively) were prepared and conjugated to PEG via an N-hydroxysuccinimide (NHS)-activated terminal. Thiolated PEI was conjugated to the mannosylated PEG via the maleimide (MAL)-activated terminal. The resulting positively charged diblock copolymers bearing mannoses (Man-PEG-b-PEI and Man3-PEG-b-PEI) were self-assembled with DNA to form PICs with lower surface charge than did their PEI building block and mean hydrodynamic diameters in the range of 100-450 nm, depending on the N/P ratio. Man3-PEG-b-PEI demonstrated a 3-4-fold greater transfection efficiency in MR-positive dendritic cell lines (THP-1, DC2.4), relative to Man-PEG-b-PEI, exhibited low cytotoxicity when compared with PEI, and showed low transfection efficiency in nondendritic HeLa cells. In preliminary in vivo experiments, Man-PEG-b-PEI/DNA and Man3-PEG-b-PEI/DNA demonstrated 2-3-fold higher gene delivery efficiency into CD11c(+) DCs collected from inguinal lymph nodes of C57/BL6 mice, when compared to PEI/DNA complexes, as shown by GFP expression measurements, 24 h post subcutaneous injection. The results indicate that the mannosylated PICs are a safe and effective gene delivery system, showing in vivo specificity toward CD11c(+) DCs.
authors.affiliation: Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, §The Shraga Segal Department of Microbiology and Immunology, Faculty of Health Sciences, and ‡Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer-Sheva, 84105, Israel.
authors.forename: Lior
authors.initials: L
authors.lastname: Raviv
authors.forename: Michal
authors.initials: M
authors.lastname: Jaron-Mendelson
authors.forename: Ayelet
authors.initials: A
authors.lastname: David
mesh_terms: D000818:Animals; D039521:CD11c Antigen / Q000235:genetics*; D002460:Cell Line; D003713:Dendritic Cells / Q000166:cytology*; D018014:Gene Transfer Techniques; D006367:HeLa Cells; D006801:Humans; D008358:Mannose / Q000737:chemistry; D051379:Mice; D011092:Polyethylene Glycols / Q000737:chemistry; D011094:Polyethyleneimine / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D014162:Transfection / Q000379:methods*
chemical_list: D039521:CD11c Antigen; D011108:Polymers; C120166:mannose polyethylenimine; D011092:Polyethylene Glycols; D011094:Polyethyleneimine; D008358:Mannose
keywords: dendritic cells; gene delivery system; mannose receptor; mannose-receptor ligands; multivalency