Jayaraj Ramamoorthi, Piedrafita David, Dynon Kemperley, Grams Rudi, Spithill Terry W, Smooker Peter M
RMIT University, Bundoora, Victoria 3083, Australia.
Vet Parasitol. 2009 Mar 23;160(3-4):230-6. doi: 10.1016/j.vetpar.2008.10.099. Epub 2008 Nov 6.
Liver flukes produce cathepsin B and cathepsin L in their excretory-secretory material. These proteases are proposed to be key virulence factors for parasite infection, and are therefore targets for vaccination. Cathepsin B is predominately released in the juvenile stage of the life cycle, while different cathepsin L's are released throughout the cycle. Three proteases (cathepsin L5, cathepsin L1g and cathepsin B) were expressed in yeast from cDNA clones isolated from adult, metacercariae and newly excysted juvenile flukes respectively. Each was used singly or in combination to vaccinate rats that were subsequently challenged with Fasciola hepatica metercercariae. Each protein induced an immune response, and all groups vaccinated with recombinant protein yielded significantly fewer and smaller flukes than the control group. Maximal protection of 83% was seen in the group vaccinated with cathepsin B and cathepsin L5 in combination.
肝吸虫在其排泄-分泌物质中产生组织蛋白酶B和组织蛋白酶L。这些蛋白酶被认为是寄生虫感染的关键毒力因子，因此是疫苗接种的靶点。组织蛋白酶B主要在生命周期的幼年期释放，而不同的组织蛋白酶L在整个周期中都有释放。分别从成虫、囊蚴和新脱囊的幼虫中分离出的cDNA克隆在酵母中表达了三种蛋白酶（组织蛋白酶L5、组织蛋白酶L1g和组织蛋白酶B）。每种蛋白酶单独或联合用于给大鼠接种疫苗，随后用肝片吸虫囊蚴攻击这些大鼠。每种蛋白质都诱导了免疫反应，并且所有接种重组蛋白的组产生的吸虫数量和大小都明显少于对照组。联合接种组织蛋白酶B和组织蛋白酶L5的组中观察到了83%的最大保护率。
