日本血吸虫合成表位肽疫苗对小鼠的保护性免疫

Protective immune response against Schistosoma japonicum elicited by immunization with synthetic mimotope peptides

为观察日本血吸虫合成表位多肽疫苗诱导的保护性免疫,将用日本血吸虫抗原免疫血清筛选噬菌体随机12肽库得到的、具有较好免疫保护性的4个模拟抗原表位短肽进行人工合成,用酶联免疫吸附实验(ELISA)检测它们的抗原性.将合成多肽分别与钥孔戚血蓝蛋白(KLH)连接后免疫昆明小鼠,第3次免疫后收集血清,检测其针对各个多肽和可溶性成虫抗原(AWA)的IgG抗体滴度,以及补体介导的小鼠体外杀日本血吸虫童虫作用.结果显示,4个合成多肽均能被相应的抗体识别,具有良好的抗原性;能诱导产生特异性IgG抗体.这些抗体在补体参与下能在体外有效毒杀血吸虫童虫.与正常小鼠血清比较,4个合成多肽免疫血清的杀童虫率分别为31.7%,41.3%,21.1%和17.3%,均具有显著性;与KLH免疫血清相比时,杀童虫率分别为23.7%,34.4%,11.8%(P=0.077,无显著性)和7.5%(P=0.102,无显著性).这些结果表明,这4个合成表位多肽具有良好的抗原性和免疫原性,与KLH连接后能诱导明显的抗体反应和显著的细胞毒作用.

To explore the humoral immune responses in mice against Schistosoma japonicum（S.japonicum） elicited by immunization with synthetic peptides, a panel of four M13 phage-originated mimotopes of three S.japonicum vaccine antigens was synthesized. Enzyme-finked immunosorbant assay（ELISA） was used to evaluate these four synthetic peptides for their antigenicity. After the peptides were conjugated to keyhole limpet hemocyanin（KLH）, the conjugates were used to immunize Kunming mice. Mice sera were collected 2 weeks after the third immunization to evaluate for their specific IgG antibodies against not only their respective homologous peptide but also soluble adult worm antigen（AWA） and for their capacity to mediate complement-dependent killing of schistosomula. That the four synthetic peptides were able to be efficiently recognized in ELISA by their respective homologous antisera showed they were all antigenic. The conjugates could induce high titer specific IgG antibodies which were effective at complement-mediated killing of schistosomula. The levels of complement-mediated killing obtained with anti-peptides antibodies were 31.7%, 41.3%, 21.1% and 17.3% respectively, when compared with normal mice sera（NMS） or 23.7%, 34.4%, 11.8% and 7.5% respectively, when compared with anti-KLH antibodies. The results showed that these four synthetic mimotope pepfides were antigenic and immunogenic. The conjugates could induce antibody responses which conferred significant levels of killing of schistosomula in vitro.