title: Efficient immunization and cross-priming by vaccine adjuvants containing TLR3 or TLR9 agonists complexed to cationic liposomes.
abstract: Complexing TLR9 agonists such as plasmid DNA to cationic liposomes markedly potentiates their ability to activate innate immunity. We therefore reasoned that liposomes complexed with DNA or other TLR agonists could be used as effective vaccine adjuvants. To test this hypothesis, the vaccine adjuvant effects of liposomes complexed to TLR agonists were assessed in mice. We found that liposomes complexed to nucleic acids (liposome-Ag-nucleic acid complexes; LANAC) were particularly effective adjuvants for eliciting CD4(+) and CD8(+) T cell responses against peptide and protein Ags. Notably, LANAC containing TLR3 or TLR9 agonists effectively cross-primed CD8(+) T cell responses against even low doses of protein Ags, and this effect was independent of CD4(+) T cell help. Ag-specific CD8(+) T cells elicited by LANAC adjuvants were functionally active and persisted for long periods of time in tissues. In a therapeutic tumor vaccine model, immunization with the melanoma peptide trp2 and LANAC adjuvant controlled the growth of established B16 melanoma tumors. In a prophylactic vaccine model, immunization with the Mycobacterium tuberculosis protein ESAT-6 with LANAC adjuvant elicited significant protective immunity against aerosol challenge with virulent M. tuberculosis. These results suggest that certain TLR agonists can be combined with cationic liposomes to produce uniquely effective vaccine adjuvants capable of eliciting strong T cell responses against protein and peptide Ags.
authors.affiliation: Department of Microbiology, Immunology, and Pathology, University of Cincinnati College of Medicine and Cincinnati Children's Hospital, OH 45229, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Zaks
authors.forename: Michael
authors.initials: M
authors.lastname: Jordan
authors.forename: Amanda
authors.initials: A
authors.lastname: Guth
authors.forename: Karen
authors.initials: K
authors.lastname: Sellins
authors.forename: Ross
authors.initials: R
authors.lastname: Kedl
authors.forename: Angelo
authors.initials: A
authors.lastname: Izzo
authors.forename: Catharine
authors.initials: C
authors.lastname: Bosio
authors.forename: Steven
authors.initials: S
authors.lastname: Dow
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000502:physiology; D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000276:immunology*; D002412:Cations; D045142:Cross-Priming; D005260:Female; D007093:Imidazoles / Q000008:administration & dosage; D008070:Lipopolysaccharides / Q000008:administration & dosage; D008081:Liposomes; D008546:Melanoma, Experimental / Q000276:immunology / Q000517:prevention & control; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009169:Mycobacterium tuberculosis / Q000276:immunology; D053594:Myeloid Differentiation Factor 88; D009838:Oligodeoxyribonucleotides / Q000008:administration & dosage; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology; D011070:Poly I-C / Q000008:administration & dosage; D015398:Signal Transduction / Q000276:immunology; D051196:Toll-Like Receptor 3 / Q000819:agonists*; D051217:Toll-Like Receptor 9 / Q000819:agonists*; D015054:Zymosan / Q000008:administration & dosage
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000276:Adjuvants, Immunologic; C408982:CPG-oligonucleotide; D019496:Cancer Vaccines; D002412:Cations; D007093:Imidazoles; D008070:Lipopolysaccharides; D008081:Liposomes; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D009838:Oligodeoxyribonucleotides; D051196:Toll-Like Receptor 3; D051217:Toll-Like Receptor 9; D010047:Ovalbumin; D015054:Zymosan; D011070:Poly I-C; C402365:resiquimod