The Immunogenicity of CRISP1 Plasmid-Based Contraceptive Vaccine can be Improved When Using Chitosan Nanoparticles as the Carrier.

Problem: To evaluate the effectiveness and security of a contraceptive vaccine using plasmid DNA encoding mouse CRISP1 as antigen and chitosan nanoparticles as the carrier.
Method of Study: Chitosan-pcDNA3.1-mCRISP1 Nanoparticles (CS-DNA NPs) were prepared and characterized in terms of morphology, zeta potential, polydispersity index, and binding capacity of pDNA. The cytotoxicity and gene transfer capability of CS-DNA NPs were assessed in COS-7 cells compared to Lipofectamine 2000(™) . Four groups of mice received three injections of 0.9% normal saline, pcDNA3.1 vector, pcDNA3.1-CRISP1, or CS-DNA NPs, respectively. ELISA was used to examine the immune responses. Fertility and mean litter size were analyzed by natural mating.
Results: CS-DNA NPs have a spherical or elliptical shape with a mean diameter of 189.3 nm, positive zeta potential, and good DNA condensation. It also showed high DNAse resistance and good transfection efficiency without cell toxicity. The titers of anti-mCRISP1 antibodies from CS-DNA NP-immunized mice were significantly higher than that of pcDNA3.1-CRISP1 group. Male and female CS-DNA NP-immunized animals were recognized with a statistically significant reduction in their fertility compared with pcDNA3.1-CRISP1-immunized mice.
Conclusion: This study demonstrated that using chitosan-DNA nanoparticles as the carrier can improve the immunogenicity of mCRISP1 DNA contraceptive vaccine with good security.
(© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)