真核表达的吕氏泰勒虫TlSP重组蛋白的免疫保护效果评价

Evaluation of immune protective effect of recombinant Theileria luwenshuni TlSP protein expressed in eukaryotes

为评价重组吕氏泰勒虫TlSP蛋白的免疫保护效果,以真核表达的不同浓度的重组TlSP抗原分别与等体积的佐剂MONTANIDE ISA 61 VG混合后充分乳化,于首次免疫后第0天和第21天分别免疫绵羊2次,于第35天进行攻蜱试验,通过观察在试验期间各组绵羊的临床症状、红细胞染虫率和特异性抗体效价等来评价免疫保护效果;空白对照组以等量PBS代替抗原进行同步参照分析。结果显示,空白对照组的绵羊出现高热、贫血和淋巴结肿胀等典型的临床症状,而2个重组蛋白免疫组只出现轻微贫血。空白对照组、免疫A组（600 g）和免疫B组（300 g）分别于攻蜱后第20天、36天和29天最早发现血液中出现泰勒虫,最高染虫率分别为8.60%、1.12%和3.00%,特异性抗体最高效价分别为1∶8 192、1∶65 536和1∶32 768。TlSP重组亚单位疫苗能刺激特异性T淋巴细胞的增殖,提高机体IL-2、IL-4和IFN-γ的分泌水平。本研究为今后羊泰勒虫病的防治奠定了基础。

To evaluate the immunoprotective efficacy of recombinant Theileria luwenshuni surface protein（r TlSP） with yeast expression system,the eukaryotic expression TlSP antigen in different concentration and the same volume of MONTANIDE ISA 61 VG adjuvant were mixed and fully emulsified.The primary immunization and second immunization were carried out on day 0 and day 21 post-1 st immunization,respectively,but the antigen of the control group was equal volume of PBS; all of sheep were challenged by field ticks on day 35 post-1 st immunization.During the trial period,the clinical symptoms were observed,and the number of Theileria in red blood cell and the titers of specific antibody were checked.The results showed that there were typical clinical symptoms of high fever,anemia,and swollen lymphnodes in the control group;but only the mild anemia was observed in two experimented groups.The Theileria in red blood cell were initially found in the control group on day 20,in experimental group A on day36,and in experimental group B on day 29 post-challenge with Haemaphysalis longicornis,respectively;the highest percentage of parasitemia was 8.60%,1.12%and 3.00%,respectively,while the highest titers of specific antibody were 1∶8 192,1∶65 536 and 1∶32 768,respectively.The recombinant TlSP protein could stimulate the proliferation of specific T lymphocytes and significantly increase the secretion of cytokines（IL-2,IL-4 and IFN-γ）.This study laid the foundation for the prevention and control of ovine and caprine theileriosis.