Physical characterization and in vivo evaluation of poloxamer-based DNA vaccine formulations.
BACKGROUND
Plasmid DNA (pDNA) vaccines have generated significant interest for the prevention or treatment of infectious diseases. Broader applications may benefit from the identification of safe and potent vaccine adjuvants. This report describes the development of a novel polymer-based formulation to enhance the immunogenicity of pDNA-based vaccines.


METHODS
Plasmid DNA was formulated with a nonionic block copolymer, poloxamer CRL1005, and the cationic surfactant benzalkonium chloride (BAK) to produce a thermodynamically stable, self-assembling system. The influence of parameters such as polymer concentration and BAK composition on the immune responses was evaluated in mice vaccinated with pDNA encoding influenza nucleoprotein.


RESULTS
At concentrations of 7.5 mg/ml CRL1005, 0.3 mM BAK and 5 mg/ml pDNA, CRL1005/BAK/pDNA particles had a mean diameter of 261 +/- 0.2 nm and a surface charge of - 11.6 +/- 0.9 mV. The negative surface charge and atomic force microscopy images suggested that pDNA binds to BAK adsorbed to the surface of poloxamer particles. The CRL1005/BAK/pDNA formulation significantly enhanced antigen-specific cellular and humoral immune responses, and increased transgene levels in muscle and serum. The complexity of the formulation was reduced by replacing the commercial BAK, which is a mixture of four alkyl chains, with a C14 BAK homolog. The substitution yielded an analytically preferable formulation with equivalent physical characteristics and immunogenicity.


CONCLUSIONS
The results suggest that the CRL1005/BAK/pDNA formulation may enhance immunogenicity by improving the delivery of pDNA-based vaccines. This formulation is currently being evaluated for the prevention of CMV-associated disease in a phase 2 clinical trial.
Hartikka
Jukka
J
Vical Incorporated, 10390 Pacific Center Court, San Diego, CA 92121-4340, USA. jhartikka@vical.com
Geall
Andrew
A
Bozoukova
Vesselina
V
Kurniadi
David
D
Rusalov
Denis
D
Enas
Joel
J
Yi
Ji-Hyun
JH
Nanci
Antonio
A
Rolland
Alain
A
D000276:Adjuvants, Immunologic / Q000378:metabolism*; D000704:Analysis of Variance; D001548:Benzalkonium Compounds / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence; D010316:Particle Size; D020442:Poloxamer / Q000378:metabolism*; D011108:Polymers / Q000378:metabolism; D019444:Vaccines, DNA / Q000276:immunology* / Q000378:metabolism
D000276:Adjuvants, Immunologic; D001548:Benzalkonium Compounds; C113154:CRL 1005; D011108:Polymers; D019444:Vaccines, DNA; D020442:Poloxamer; D004247:DNA