猴痘自组装纳米颗粒候选疫苗的制备及免疫应答特征研究

Preparation and immune response characterization of self-assembled nanoparticle vaccine candidates for monkeypox

目的 本研究旨在制备自组装纳米颗粒猴痘候选疫苗并研究其免疫应答特征,为其疫苗设计提供可参考的试验数据。方法 利用原核系统表达纯化抗原蛋白A29L-SpyTag和骨架蛋白Mi3-SpyCatcher,化学组装制备纳米颗粒A29L-Mi3,皮下免疫小鼠,通过ELISA测定抗体效价、空斑试验测定抗体中和、流式细胞术测定淋巴细胞分泌细胞因子情况,并描述其免疫应答特征。结果 成功制备A29L-Mi3纳米颗粒,颗粒呈中空笼状均匀分布,其粒径平均为(29±0.19) nm。A29L-Mi3纳米颗粒候选疫苗联合SP01佐剂后,中和抗体效价强于A29L蛋白候选疫苗,且A29L-Mi3纳米颗粒候选疫苗免疫2次即能够获得免疫3次相近滴度的中和抗体。A29L-Mi3纳米颗粒候选疫苗激活的小鼠T淋巴细胞免疫应答水平高于A29L蛋白候选疫苗。结论 成功体外组装制备出结构均一的A29L-Mi3蛋白纳米颗粒,具有较强的免疫原性,联合SP01佐剂后中和能力提高,为免疫程序的优化提供参考数据。细胞免疫应答水平均高于单独的A29L蛋白,为猴痘疫苗的设计与研发提供借鉴。

The aim of this study was to prepare a self-assembled nanoparticle monkeypox vaccine candidate and study its immune response characteristics,so as to provide reference test data for its vaccine design.The antigen protein A29L-SpyTag and the backbone protein Mi3-SpyCatcher were expressed and purified by prokaryotic system,and nanoparticles A29L-Mi3 were prepared by chemical assembly,then the antibody titers were determined by ELISA,the antibody neutralization was determined by plaque test,and the cytokine secretion of lymphocytes was determined by flow cytometry to describe the immune response characteristics.Data showed that A29L-Mi3 nanoparticles were successfully prepared,and the particles were uniformly distributed in hollow cages,with an average particle size of(29±0.19) nm.After the A29L-Mi3 nanoparticle vaccine candidate was combined with SP01 adjuvant,the neutralizing antibody titer was stronger than that of the A29L protein candidate,and the A29L-Mi3 nanoparticle vaccine candidate could obtain neutralizing antibodies with similar titers after two immunizations.The level of mouse T lymphocyte immune response activated by the A29L-Mi3 nanoparticle vaccine candidate was higher than that of the A29L protein vaccine candidate.In conclusion,A29L-Mi3 protein nanoparticles with uniform structure have successfully assembled in vitro,which has strong immunogenicity and improved neutralization ability after combination with SP01 adjuvant,thus provided reference data for the optimization of immune programs.In addition,the level of cellular immune response is higher than that of A29L protein alone,which provides a reference for the design and development of monkeypox vaccine.