Application of Archaeosome Nanoparticles as a DNA Vaccine Delivery System and Evaluation of its Effect in a C57BL/6 Tumor Model

More than 99% of cervical cancers contain human papillomavirus (HPV), particularly the high-risk HPV type 16 (HPV-16). Among therapeutic HPV vaccines, DNA vaccines have emerged as a potentially promising approach. The main problem with DNA vaccination is the efficient delivery of the genes. A different delivery system has been used to bypass this problem. Archaeosomes have shown high stability during oxidative stress. In this study, we prepared the archaeosome Halobacterium salinarum polar lipid and used it as a delivery system and adjuvants for formulation with the E6/E7/L1 chimeric plasmid as an HPV vaccine candidate.
The recombinant pIRES2-plasmid that contained an E6/E7/L1 chimeric gene of HPV were purified after extraction. Halobacterium salinarum total polar lipids were prepared according to a method by Bligh and Dyer. The archaeosome-pDNA complex was prepared by the addition of plasmid DNA to an archaeal lipid solution and the mixture kept at room temperature to allow for complex formation. Particle sizes and zeta potential of the samples were measured using dynamic light scattering. We measured the relative tumor volume after administration of TC-1 cells to C57BL/6 mice.
Zeta potential of the anionic archaeosomes was -6.84mV while archaeosome-pDNA complexes were -29 mV. The highly negative zeta potential of archaeosome-pDNA complexes demonstrated excellent loading of the plasmid on the nanoparticle surface and electrostatic stability. The results showed that the archaeosome-containing E6/E7/L1 chimeric gene significantly inhibited the rate of tumor growth in comparison with the control groups.
Archaeosomes are easy and cost-economic to prepare and highly stable. They may hold tremendous promise as vaccine delivery vehicles