摘要
目的:探索减毒沙门氏菌运送CD8+T细胞表位诱导机体产生特异性细胞免疫应答的规律性。方法:通过构建融合表达OVA257~264aa和LCMVNP118~132aaCD8+T细胞表位的原核表达质粒ptG2F,以电穿孔法转化减毒鼠伤寒沙门氏菌SL7207,筛选重组菌SL7207(ptG2F)。采用静脉注射免疫C57BL/6和BALB/c小鼠,间隔2wk,分别于第2次和第3次免疫后,取免疫小鼠脾细胞,用ELISPOT法检测特异性IFN-γ分泌细胞和IL-4分泌细胞。结果:携带CD8+T细胞表位的重组菌SL7207(ptG2F)能诱导产生细胞免疫应答。在提呈OVACD8+T细胞表位时,2次免疫后,诱导产生的细胞免疫应答趋向于Th1;而在3次免疫后,呈现Th1/Th2的平衡转换。在提呈LCMVNPCD8+T细胞表位过程中,Th2免疫应答水平高于Th1,且有增强趋势。结论:减毒沙门氏菌可以有效运送CD8+T细胞表位并诱导产生特异细胞免疫应答,这为减毒细菌作为运送载体的研究提供了参考依据。
AIM： To investigate cellular immune responses against CD8^＋ T cell epitopes delivered by attenuated Salmonella. METHODS： Prokaryotic expression plasmid ptG2F, carrying the oligonucleotide fragment encoding CDS^＋ T cell epitope of OVA 257 -264aa and LCMV NP 118 - 132aa fused with GFP gene was constructed and electrotransformed into the attenuated strain SL7207 of Salmonella typhimurium. The recombinant bacteria, named as SL7207 （ptG2F）, were screened out. C57BL/6 and BALB/c mice were immunized intravenously with SL7207 （ptG2F） at two weeks intervals. Murine IFN-y and IL-4 secreting cells were detected in murine splenocytes after second and third immunization by Enzyme-linked immunospot assay （ELISPOT）. RESULTS： The recombinant bacteria SL7207 （ptG2F） induced cellular immune responses. When OVA CD8^＋ T cell epitope was presented by the recombinant bacteria, the immune responses were biased toward Th1 response after second immunization and then switched to the Th1 and Th2 balance after third immunization. In contrast, when the LCMV NP CD8^＋ T cell epitope was presented, the level of Th2 immune response was higher than that of Th1 after both second and third immunization. CONCLUSION： Attenuated Salmonella can effectively deliver the CD8^＋ T cell epitopesand induce specific cellular immune responses. The results provide useful information for developing attenuated bacteria as novel vectors.
出处
《细胞与分子免疫学杂志》
CAS
CSCD
北大核心
2006年第2期137-140,共4页
Chinese Journal of Cellular and Molecular Immunology
基金
国家杰出青年科学基金资助项目(No.30425031)
全国优秀博士学位论文作者专项资助项目(No.FANEDD200358)
