白介素2基因佐剂协同单纯疱疹病毒1型糖蛋白D核酸疫苗免疫诱导的特异性免疫应答

Enhancement of Herpes Simplex Virus-1 Glycoprotein-D DNA Vaccine Induced Specific Immune Responses by Coimmunization with Interleukin-2 Genetic Adjuvant

目的研究白介素2(IL-2)cDNA协同单纯疱疹病毒1型(HSV-1)gD核酸疫苗免疫对机体体液免疫和细胞免疫应答的影响,以及在HSV-1病毒角膜攻击时的保护效果。方法利用pcDNA3.1载体分别构建HSV-1糖蛋白D和IL-2的真核表达质粒pgD和pIL-2,体外鉴定其表达。动物实验分为pcDNA3.1空载体对照组、pgD单独免疫组和pgD+pIL-2联合免疫组3组,具体为通过肌肉免疫接种BALB/c小鼠3次,间隔2周,每次接种质粒100μg,第3次免疫后2周,用酶联免疫吸附试验(ELISA)检测抗体滴度并做亚型分析,利用3H-TdR掺入法进行Th细胞增殖实验,ELISA试剂盒检测Th细胞分泌的IL-2、IFN-γ和IL-10水平,耳廓肿胀实验检测迟发型超敏反应(DTH)反应;HSV-1病毒角膜攻击后,裂隙灯显微镜观察角膜上皮病变。结果与pgD单独免疫组相比,pIL-2的协同免疫可以显著提高IgG2a抗体滴度、Th细胞增殖反应和DTH反应,Th细胞分泌IL-2和IFN-γ水平也显著提高,IL-10水平明显下降。在动物保护实验中,pIL-2的协同免疫明显增强了pgD疫苗在病毒攻击时对角膜的保护效果。结论IL-2cDNA的协同免疫可以显著提高pgD核酸疫苗诱导的体液免疫和细胞免疫应答水平,增加核酸疫苗的免疫保护效果。

Objective To investigate the immune responses and protection from virus challenge, induced by the coinjection of IL-2cDNA with herpes simplex virus type 1(HSV-1)glycoprotein-D(gD)DNA vaccine. Methods Two DNA vaccines(pgD and pIL-2)were constructed by inserting the gD geneand IL-2 cDNA into the eukaryotic expression vector pcDNA3.1, respectively. The BALB/c mice were inoculated intramuscularly three times at 2-week intervals. Two weeks after the final immunization, mice were bled for antibody assay and spleen cells were separated for Th cell proliferation and cytokine assays. Delayed type hypersensitivity(DTH)response was detected by the pinna-swelling test. Corneal pro-tection under HSV-1 virus challenge was continuously observed with slit-lamp microscope. Results IL-2 cDNA coinjection remarkably enhanced the specific IgG2a level when compared with gD plasmid vacc-ination alone. Th cell proliferation and secretion of cytokines(IL-2 and IFN-γ)were significantly incr-eased by IL-2 cDNA coinjection. However, the production of IL-10 was inhibited. The DTH response was also enhanced by IL-2 coinjection. When the mice were challenged with HSV-1, the cornea epith-elial lesions were significantly alleviated by IL-2 coinjection as compared with gD vaccination alone. Conclusion IL-2 cDNA can enhance both the humoral and cellular immune responses, and thus increase the vaccine potency.