弓形虫多价DNA疫苗免疫途径与效果评价

Evaluation on immunizing effect and route of plural DNA vaccine to Toxoplasma gondii

目的观察弓形虫多价DNA疫苗经不同免疫途径对小鼠的免疫效果。方法通过基因重组技术构建弓形虫多价抗原与霍乱毒素融合基因的真核表达质粒pSAG1-2-CTA2/B;碱裂解法大量制备重组质粒经肌注、滴鼻途径免疫小鼠,每2周免疫1次,共3次,于免疫前和免疫后4周断尾取血测定IgG抗体和血清中的细胞因子干扰素(IFN-γ)、白介素(IL-4);取免疫小鼠脾脏测定T淋巴细胞增殖活性、自然杀伤细胞(NK细胞)活性及T细胞亚群。结果经肌注免疫的小鼠IgG抗体生成明显(P<0.05),经滴鼻免疫的小鼠细胞免疫水平明显增强(P<0.01)。同时经2种途径免疫的小鼠体液免疫和细胞免疫水平均明显增强(P<0.01),且免疫鼠生存率大大提高(P<0.05)。结论多种免疫途径结合可有效增强弓形虫多价DNA疫苗的免疫原性。

Objective To assess the effect of plural DNA vaccination on Toxoplama gondii via different immunized routes. Methods Recombinant plasmid pSAGI - 2 - CTA2/B encoding SAGI and SAG2 of T. gondii antigen and CTA2/B subunit of cholera toxin was constructed by gene engineering. Largescale preparation of plasmid DNA by alkaline lysis. BALB/ c mice were immunized intramuscular or intranasal with plasmid pSAG1 - 2 - CTA2/B. Booster immunizations were employed 2 more times at 2 - week interval. Humoral and cellular responses were assayed using ELISA for the determination of Ab and IFN - γ, as well as IL - 4, the proliferation activity of T lymph cells and the activity of NK killer by means of methyl thiazolyl tetrazolium（MTT） assay, flow cytometry （FCM） was also used to sort the lymphocyte subsets of spleen cells. Results Hu- moral and cellular immuno- response are enhanced in mice immunized via both of the two routes and most prolonged survival time was got in this challenging vaccinated mice group. While only high level of IgG or only high level of cellular was detected in mice immunized intramuscular or intranasal. Conclusion The immunity of DNA vaccine of T. gondii could be enhanced markedly by immunized mice via several route.