不同免疫方式对新冠DNA疫苗应答效果的影响

The effect of different immunization routes on the response of SARS-CoV-2 DNA vaccine

目的探究气管灌注和电脉冲肌肉导入2种免疫方式对新型冠状病毒(SARS-CoV-2)DNA疫苗免疫应答的影响。方法利用真核表达载体pVAX-1,设计并构建p RBD、p S-2P和p S-2P.3513种SARS-CoV-2 DNA疫苗。在第0、2和4周采用气管灌注以及电脉冲肌肉导入2种方式免疫小鼠。末次免疫后2周,ELISA检测血清及阴道灌洗液特异性IgG抗体水平,肺泡灌洗液(bronchoalveolar lavage fluid,BALF)、鼻腔灌洗液(nasal solution,NS)以及阴道灌洗液(vaginal wash)特异性sIgA抗体水平;ELISpot检测免疫后小鼠脾细胞分泌特异性IFN-gamma的水平。结果气管灌注及电脉冲肌肉导入2种方式免疫SARS-CoV-2DNA疫苗,仅气管灌注免疫可诱导特异性呼吸道黏膜sIgA应答,而电脉冲肌肉导入诱导了更强的细胞免疫应答。与气管灌注pRBD相比,气管灌注pS-2P和p S-2P.351可诱导更强的黏膜免疫应答和细胞免疫应答。结论气管灌注和电脉冲肌肉导入2种免疫方式均可诱导特异性体液免疫以及细胞免疫应答,电脉冲肌肉导入诱导了更强的细胞免疫应答,而气管灌注在诱导呼吸道黏膜免疫应答方面更具优势。

To explore the effects of two immunization routes,intratracheal(i.t.)immunization and intramuscular injection with electroporation(i.m.+EP),on the immune response of the SARS-CoV-2 DNA vaccine,three SARSCoV-2 DNA vaccines pRBD,pS-2 P and pS-2 P.351 were designed and constructed by using eukaryotic expression vector pVAX-1.The mice were immunized by intratracheal instillation or intramuscular injection with electroporation at 0,2 and 4 weeks.The level of specific IgG in serum and vaginal lavage fluid,and the level of specific sIgA in BALF,nasal solution(NS)and vaginal wash were evaluated;specific IFN-gamma secreted by mouse splenocytes was tested by ELISpot.Data showed only intratracheal immunization could induce specific respiratory mucosal sIgA response,while intramuscular injection with electroporation could induce stronger cellular immune response.Compared with pRBD intratracheal immunization,intratracheal immunization with pS-2P and pS-2P.351 could induce stronger mucosal and cellular immune responses.In conclusion,both intratracheal immunization and intramuscular injection with electroporation could induce specific humoral and cellular immune response.Intramuscular injection with electroporation induces a stronger cellular immune response,and intratracheal immunization has more advantages in inducing respiratory mucosal immune response.