沙门菌鞭毛蛋白增强新城疫病毒融合蛋白在小鼠中的免疫原性

Adjuvant Activity of the Flagellin of Salmonella typhimurium in the Immune Response of Fusion Protein of Newcastle Disease Virus in Mice

目的:分析沙门菌鞭毛蛋白对新城疫病毒(NDV)融合蛋白(F蛋白)免疫原性的增强作用。方法:提取鼠伤寒沙门菌SL7207株鞭毛蛋白,将鞭毛蛋白与F蛋白以皮下注射的方式联合免疫C3H/HeJ小鼠,间隔2周免疫,共免疫3次。分别在第2次免疫后2周和第3次免疫后2周采集血清,应用ELISA法测定小鼠血清抗体;在第3次免疫后2周取免疫小鼠脾脏细胞,检测IFN-γ和IL-4特异性分泌细胞。结果:鞭毛蛋白与F蛋白联合免疫能诱导产生特异性的免疫应答,血清抗体水平显著高于F蛋白单独免疫组;在脾脏细胞中,检测到较高水平的IFN-γ和IL-4分泌细胞,免疫应答以Th1型为主。结论:鞭毛蛋白与F蛋白的联合免疫,可显著增强F蛋白的免疫原性,显示出鞭毛蛋白良好的免疫佐剂效应。

Objective： To determine the adjuvant activity of the flagellin of Salmonella typhimurium in the immune response of fusion protein（F） of Newcastle disease virus（NDV）. Methods： The F protein was expressed in E.coli BI21 and the flagellin was exn＇acted from S.typhimurium and verified with molecular weight of 46000 or 51000 by SDS-PAGE re- spectively. C3H/HeJ mice were immunized s.c. wih flagellin, F protein, F protein with flagellin or Freund＇s adjuvant re- spectively at day 0, 14 and 28. Seurm were collected from mice after the second and third immunization, and the specific antibody titers were detected by ELISA. Cells from spleen were collected from mice after third immunization, and the spe- cific IFN-^-secreting cells and IL-4-secreting cells were detected by ELISPOT assay using F protein as stimulus. Re- suits： Serum antibody responses were developed in mice immunized with flagellin mixed F protein, and there was signifi- cant difference compared with mice immunized with F protein. Furthermore, in splenocytes, immune responses against F protein were biased towards Thl type, the h＇equency of IFN-＇y-secreting cells was much higher than that of IL-4-secreting cells. Conclusion： These results suggested that F protein combined with flagellin not only can induce humoral immune re- sponses, but also can elicit specific cellular immune responses after S.typhimurium can act as an effective adjuvant in the veterinary.