Enhancing\nVaccine Efficacy with Polyethylenimine-Modified\nLovastatin-Loaded Nanoparticle Pickering Emulsion Adjuvant

Despite\nthe potent immunoadjuvant properties of mevalonate pathway\ninhibitors, their application is constrained by poor solubility and\ninstability. In this study, we developed a cationic nanoparticle-stabilized\nPickering emulsion loaded with lovastatin (Lov-PPE), using polyethylenimine\n(PEI)-modified PLGA nanoparticles and squalene as carriers. The system\nwas prepared and tested by evaluating the physicochemical properties\nand adjuvant efficacy of the Lov-PPE. Lov-PPE/O demonstrated good\nparticle size distribution and zeta potential, with an adsorption\nefficiency of up to 73.07%. The immunization results showed that Lov-PPE/O\nsignificantly promoted the production of OVA-specific IgG antibodies,\nactivated CD4<sup>+</sup> and CD8<sup>+</sup> T cells, and induced\na strong mixed Th1/2 immune response. Additionally, safety assessments\nindicated that Lov-PPE/O has good <i>in vivo</i> safety.\nThis study demonstrates that the PEI-modified lovastatin PLGA nanoparticle\nPickering emulsion (Lov-PPE) is an effective vaccine adjuvant capable\nof significantly enhancing humoral and cellular immune responses while\npossessing good safety, offering a new strategy for vaccine formulation\ndevelopment.