Construction And Evaluation In Vitro Of DC-targeted Aptamer-modified Pseudomonas Aeruginosa DNA Vaccine Delivery System

Objective To construct and evaluate a DC-targeted aptamer-modified Pseudomonas aeruginosa(PA)DNA vaccine delivery system in vitro.Methods The cationic liposome was prepared by ethanol injection method,and the cationic liposome loading pVAX1-OprF-VP22(Lip-pOprF-VP22)was prepared by electrostatic adsorption method.The encapsulation efficiency,cytotoxicity and transfection rate to DC2.4 in vitro of Lip-pOprF-VP22 with different mass ratios of DOTAP/pDNA were discussed,respectively.The particle size and zeta potential of Lip-pOprF-VP22 with best mass ratio were screened.Then Aptamer-modified cationic liposome loading pVAX1-OprF-VP22(Apt-Lip-pOprF-VP22)was prepared by post-insertion method.Finally,the expression of OprF protein and its effect on the maturation of bone marrow-derived dendritic cells(BMDCs)were detected after Apt-Lip-pOprF-VP22 transfecting DC2.4.Results With the mass ratio of DOTAP/pDNA increasing,the encapsulation efficiency of Lip-pOprF-VP22 gradually increased.And pVAX1-OprF-VP22 with the mass ratio of 5:1 was well encapsulated.When Lip-pOprF-VP22 with different mass ratios of DOTAP/pDNA transfected DC2.4 for 24 h or 48 h,the survival rates of DC2.4 were all above 80%.As the mass ratio of DOTAP/pDNA increased from 2:1 to 10:1,the transfection rate increased at first and then decreased.Lip-pOprF-VP22 with the mass ratios of DOTAP/pDNA of 4:1 or 5:1 have the relatively high transfection rates,Lip-pOprF-VP22 with the mass ratio of 5:1 was(171.67±1.27)nm in the particle size and was(11.30±0.57)mV in the Zeta potential.Furthermore,Apt-Lip-pOprF-VP22 expressed OprF protein and significantly promote the maturation of BMDCs.Conclusion Constructed DC-targeted aptamer-modified PA DNA vaccine delivery system of Apt-Lip-pOprF-VP22 successfully.And the delivery system could target and transfer to DC,and then promote the maturation of DC.