The combination of stabilized plasmid lipid particles and lipid nanoparticle encapsulated CpG containing oligodeoxynucleotides as a systemic genetic vaccine.
BACKGROUND
DNA vaccines offer unique potential for generating protective and therapeutic immunity against infectious and malignant diseases. Unfortunately, rapid degradation and poor cellular uptake has significantly limited the efficacy of 'naked' plasmid DNA vaccines. We have previously described stabilized plasmid lipid particles (SPLP) as effective nonviral gene delivery vehicles for the transfection of tumours at distal sites following intravenous administration. Based on their low toxicity and favourable transfection profile following systemic administration, we investigate SPLP as gene delivery vehicles for the generation of a systemically administered genetic vaccine.


METHODS
The uptake of SPLP and their ability to transfect splenic antigen presenting cells (APC) following systemic administration is assessed through fluorescently-labelled SPLP in combination with phenotype markers and a very sensitive flow cytometry-based assay for the detection of the transgene, beta-galactosidase. The priming of antigen-specific adaptive and humoural immune responses following vaccination with SPLP alone or in combination with liposomal nanoparticle encapsulated CpG-ODN containing oligodeoxynucleotides (LN CpG-ODN) is characterized through the use of antigen-specific cytotoxicity assays, interferon-gamma secretion assays and enzyme-linked immunosorbant assay.


RESULTS
We demonstrate that SPLP are taken up by and transfect APC in the spleen following intravenous administration and that, in the presence of a strong immunostimulatory signal provided by LN CpG-ODN, are able to prime transgene-specific humoural and cellular immune responses.


CONCLUSIONS
SPLP represent an effective candidate for the nonviral delivery of a systemic genetic vaccine when combined with additional immune stimulation provided by LN CpG-ODN.
Wilson
Kaley D
KD
Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada. kaley@interchange.ubc.ca
de Jong
Susan D
SD
Kazem
Mikameh
M
Lall
Ryan
R
Hope
Michael J
MJ
Cullis
Pieter R
PR
Tam
Ying K
YK
D000818:Animals; D000938:Antigen-Presenting Cells / Q000378:metabolism; D018845:CD11 Antigens / Q000378:metabolism; D002478:Cells, Cultured; D005260:Female; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000008:administration & dosage; D008055:Lipids / Q000737:chemistry; D008081:Liposomes / Q000008:administration & dosage*; D051379:Mice; D008807:Mice, Inbred BALB C; D053758:Nanoparticles / Q000008:administration & dosage*; D009838:Oligodeoxyribonucleotides / Q000008:administration & dosage*; D014162:Transfection; D019444:Vaccines, DNA / Q000008:administration & dosage*
D018845:CD11 Antigens; C408982:CPG-oligonucleotide; D008055:Lipids; D008081:Liposomes; D009838:Oligodeoxyribonucleotides; D019444:Vaccines, DNA