title: pDNA-lipoplexes engrafted with flagellin-related peptide induce potent immunity and anti-tumour effects.
abstract: Complexes of cationic lipids and DNA (lipoplexes) are widely used for non-viral gene delivery and DNA vaccine development, but cationic lipids are toxic and promote non-specific interactions with cells, leading to poor efficacy. Near-neutral lipoplexes, on the other hand, can obviate toxicity, but a convenient means to target them to specific cells such as dendritic cells (DCs) has been lacking. Here, we show that a His-tagged flagellin-derived peptide (denoted 9Flg), previously reported to promote binding of liposomal antigen to TLR5-expressing cells, can be used to target near-neutral pDNA-lipoplexes incorporating the chelator lipid NTA(3)-DTDA (3(nitrilotriacetic acid)-ditetradecylamine) to DCs and other antigen-presenting cells (APCs). Thus, we show that pDNA-lipoplexes engrafted with 9Flg target pDNA to APCs in vitro and in vivo. Following i.v. administration, radiolabelled 9Flg-lipoplexes exhibited increased accumulation in spleen, lung and liver. Vaccination of C57BL/6 mice with 9Flg-lipoplexes containing either pcDNA3.1-SIIN (pSIIN) or a Kunjin virus replicon-based vector (pKUN), each encoding the epitope OVA(257-264) (SIINFEKL), induced Ag-specific T cell priming, and elicited strong cellular immunity as reflected by a marked increase in the number of Ag-responsive IFN-γ-producing CD8(+) T cells. Importantly, compared to i.m. injection of these SIINFEKL-encoding pDNAs in naked form, the i.v. administration of pSIIN or pKUN in 9Flg-lipoplexes to C57BL/6 mice induced a significantly more potent anti-tumour response in the B16-OVA melanoma tumour model. The targeting of near-neutral 9Flg-lipoplexes bearing pDNA encoding tumour antigens to TLR5 on APCs, therefore, is a powerful approach for developing more effective DNA vaccines and immunotherapies.
authors.affiliation: Division of Biomedical Science and Biochemistry, Research School of Biology, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, 0200, Australia.
authors.forename: Abdus
authors.initials: A
authors.lastname: Faham
authors.forename: Thomas
authors.initials: T
authors.lastname: Herringson
authors.forename: Chris
authors.initials: C
authors.lastname: Parish
authors.forename: Andreas
authors.initials: A
authors.lastname: Suhrbier
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Khromykh
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Altin
mesh_terms: D000588:Amines / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D000951:Antigens, Neoplasm / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D019496:Cancer Vaccines / Q000276:immunology* / Q000494:pharmacology; D002460:Cell Line; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D005260:Female; D005408:Flagellin / Q000276:immunology*; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors / Q000276:immunology*; D057809:HEK293 Cells; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D008055:Lipids / Q000276:immunology*; D008546:Melanoma, Experimental / Q000276:immunology / Q000517:prevention & control / Q000628:therapy; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009571:Nitrilotriacetic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D010455:Peptides / Q000276:immunology; D019444:Vaccines, DNA / Q000276:immunology* / Q000494:pharmacology
chemical_list: D000588:Amines; D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D015395:Histocompatibility Antigens Class I; D008055:Lipids; D010455:Peptides; D019444:Vaccines, DNA; C405382:nitrilotriacetic acid ditetradecylamine; D005408:Flagellin; D009571:Nitrilotriacetic Acid