National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China.
Vet Parasitol. 2013 Mar 31;193(1-3):1-7. doi: 10.1016/j.vetpar.2012.12.019. Epub 2012 Dec 20.
Eimeria parasites are obligate intracellular apicomplexan protists that can cause coccidiosis, resulting in substantial economic losses in the poultry industry annually. As the component of anticoccidial vaccines, seven Eimeria spp. of chickens are characterized with potent immunogenicity. Whether genetically modified Eimeria spp. maintains this property or not needs to be verified. In this study, two identical transgenic lines of Eimeria tenella were developed by virtue of single sporocyst isolation from a stably transfected population expressing fused protein of M2 ectodomain of avian influenza virus (M2e) and enhanced yellow fluorescent protein (EYFP). The chromosomal integration and expression of M2e-EYFP were confirmed by Southern blot, plasmid rescue and Western blot analysis. We found that the reproduction of transgenic parasites was higher than that of the parental strain. Chickens challenged with wild type E. tenella after immunization with 200 oocysts of transgenic parasites had similar performance compared to those in non-immunized and non-challenged group. In another trial, the performance of transgenic parasite-immunized birds was also comparable to that of the Decoquinate Premix-treated chickens. These results suggest that this transgenic line of E. tenella is capable of inducing potent protection against homologous challenge as a live anticoccidial vaccine. Taking together, our study indicates that transgenic eimerian parasites have the potential to be developed as a vaccine vehicle for animal use in the future.
艾美耳球虫是专性细胞内顶复门原生动物，可引起球虫病，每年给家禽业造成巨大的经济损失。作为抗球虫疫苗的组成部分，七种鸡艾美耳球虫具有很强的免疫原性。遗传修饰的艾美耳球虫是否保持这种特性需要验证。在这项研究中，通过从稳定转染表达融合蛋白的群体中单一裂殖子分离，开发了两种相同的柔嫩艾美耳球虫转基因系，该融合蛋白由禽源流感病毒（M2e）的外膜 M2 结构域和增强型黄色荧光蛋白（EYFP）组成。通过 Southern blot、质粒拯救和 Western blot 分析证实了 M2e-EYFP 的染色体整合和表达。我们发现，转基因寄生虫的繁殖率高于亲本株。用 200 个卵囊的转基因寄生虫免疫后，用野生型柔嫩艾美耳球虫攻虫的鸡与未免疫和未攻虫组的鸡表现相似。在另一项试验中，转基因寄生虫免疫鸡的表现也与癸氧喹酯预混剂处理鸡相当。这些结果表明，这种柔嫩艾美耳球虫的转基因系能够诱导对同源性攻虫的强烈保护作用，可作为一种活的抗球虫疫苗。综上所述，我们的研究表明，转基因艾美耳球虫有可能在未来被开发为动物用疫苗载体。
