摘要
目的以胃癌特异性多肽抗原MG7为靶点,CpG寡核脱氧核苷酸为佐剂研制胃癌特异性纳米疫苗,并观察其对小鼠的免疫效能及其作用。方法人工合成胃癌MG7-抗原(MG7-Ag)的模拟表位多肽,用磁力超声法将其与新型免疫佐剂CpG共包封于纳米乳剂中,通过透析纯化,高效液相色谱(HPLC)检测其包封效率。所制备纳米疫苗免疫健康BALB/C小鼠,通过酶联免疫吸附法(ELISA)测定血清中抗MG7抗体的效价;酶联免疫斑点法(ELISPOT)测定小鼠脾细胞毒性T淋巴细胞活性,流式细胞仪检测淋巴细胞分型。同时,用表达MG7-Ag的小鼠艾氏腹水瘤细胞对免疫小鼠进行肿瘤攻击,观察疫苗对小鼠的保护作用;对成瘤小鼠进行疫苗治疗,观察疫苗的抑瘤率。结果成功制备了胃癌特异性MG7-Ag的纳米疫苗,并具有较好的包封率和较高的稳定性,可诱导小鼠产生特异性MG7抗体,ELlS- POT检测共包封组与对照组相比分泌干扰素(IFN)-γ的活性细胞明显增高,流式细胞仪分析显示主要活性细胞为CD4^+淋巴细胞。抑瘤实验结果共包封疫苗组肿瘤抑瘤率达82.5%,较对照组(1.8%)显著增高。结论所制备的MG7抗原肽与佐剂共包封纳米疫苗可以诱导小鼠产生较强的抗肿瘤免疫反应,并具有一定保护和治疗作用。
Objective To develop a peptide vaccine using new nano-technology based on MG7 Ag mimotope of gastric cancer and CpG oligonucleotide（ODN） as adjuvant and evaluate its efficacy and protective effect. Methods To synthesize MG7 mimotope peptide and encapsulate it with adjuvant CpG ODN into nanoemulsion using magnetic and ultrasonic technique, dialyse, purify and determine efficiency with HPLC. BALB/C mice were immunized intravenously with nanovaccine. Serum titer of MG7 antibody was detected by ELISA. ELISPOT assay was used to test the cytotoxicity of murine spleen cells. Ehrlich ascites carcinoma cells expressing MG7-Ag were used in tumor challenge assay to evaluate the protective effect of the immunization. Tumor inhibiting rate was evaluated on mice bearing tumor. Results MG7 nano-vaccine was successfully constructed with high stability and encapsulation efficiency. It was found that immunization using MG7-Ag mimotope peptide co-encapsulated with CpG ODN within the same nanoemulsion enhanced the serum antibody and interferon（IFN）-γ induction significantly when compared with mice immunized with MG7-peptide encapsulated in nanoemulsion alone. Immunization using free CpG ODN plus MG 7-Ag mimotope peptide encapsulated in nanoemulsion or MG7 mimotope peptitte and CpG ODN encapsulated in separate nanoemulsion could not achieve the same effect. Intracellular flow cytometric analysis found that the IFN-γ response was contributed by CD4 ^＋ T-cells. Tumor chalienge experiment showed that the tumor masses formed in the mice immunized with coencapsulated nanovaccine were markedly smaller than those in the mice immunized with nanovacine encapsulated with antigen peptide alone. And the coencapsulated group got the highest tumor inhibition rate.Conclusion Nanovaccine based on the MG7-Ag mimotope is immunogenic which can induce specific immunity response against tumor in mice. And the vaccine is partially protective. The experiments suggest that a vaccinal approach using nano-delivery system carrying tumoral epitope a
出处
《中华消化杂志》
CAS
CSCD
北大核心
2007年第8期520-524,共5页
Chinese Journal of Digestion
基金
国家863计划课题(2001AA215421)
关键词
胃肿瘤
抗原
疫苗
Stomach neoplasms
Antigen
Vaccine
