Modirrousta Hossein, Habibi Gholamreza, Shayan Parviz, Afshari Asghar, Mirjalili Ali, Abdigoudarzi Mohamad
Department of Wild Life Research, Razi Vaccine and Serum Research Institute, Agriculture Research, Education and Extension Organization, Karaj, Iran.
Department of Parasite Vaccine Research and Production, Razi Vaccine and Serum Research Institute, Agriculture Research, Education and Extension Organization, Karaj, Iran.
Iran J Parasitol. 2019 Oct-Dec;14(4):572-583.
The protozoan parasite is the causative agent of tropical theileriosis in cattle. Vaccination is recommended by administration of attenuated schizont-infected cell lines. The expected protective immunity post-vaccination can be demonstrated by challenge test through inoculation of highly virulent infective sporozoites. The aim of this study was to produce tick infected with (local strain) for preparation of tick-derived sporozoite stabilates for molecular characterization and infectivity test assay.
A local strain was used for experimental infection of calves. A field isolate of was isolated, laboratory-reared and infected by blood-feeding on infected above-mentioned calves. The infectivity of calf, tick and prepared stabilate were confirmed by clinical signs of theileriosis, microscopic inspection, RT-PCR and in vitro cell culture.
The tick stabilate was prepared and cryopreserved in liquid nitrogen. The infectivity of the tick stabilate was verified by in vivo bioassay, in vitro cell culture infection, microscopic inspection in salivary glands and RT-PCR assay. The in vitro produced cell line in this study was characterized by Cytochrome b gene analyzing.
The infectivity of a new prepared tick-derived sporozoite stabilate was confirmed in susceptible calves; by microscopically, post mortem, tick microscopic and molecular assays. Moreover, naïve PBMCs were transformed and proliferated by infected tick stabilate to immortal schizont infected cell line. The potent infective sporozoite tick derived stabilate could be used for vaccine efficacy and challenge test as well as in vaccine development.
原生动物寄生虫是牛热带泰勒虫病的病原体。建议通过接种减毒裂殖体感染细胞系进行疫苗接种。接种疫苗后预期的保护性免疫可通过接种高毒力感染性子孢子的攻毒试验来证明。本研究的目的是制备感染（本地株）的蜱，以制备蜱源性子孢子稳定物用于分子表征和感染性试验分析。
使用本地株对犊牛进行实验性感染。分离出一种泰勒虫的野外分离株，在实验室饲养，并通过吸食上述感染犊牛的血液进行感染。通过泰勒虫病的临床症状、显微镜检查、逆转录-聚合酶链反应（RT-PCR）和体外细胞培养来确认犊牛、蜱和制备的稳定物的感染性。
制备了蜱稳定物并保存在液氮中。通过体内生物测定、体外细胞培养感染、唾液腺显微镜检查和RT-PCR测定验证了蜱稳定物的感染性。通过细胞色素b基因分析对本研究中体外产生的细胞系进行了表征。
通过显微镜检查、死后检查、蜱显微镜检查和分子测定，在易感犊牛中证实了新制备的蜱源性子孢子稳定物的感染性。此外，未接触过的外周血单核细胞（PBMCs）被感染蜱稳定物转化并增殖，形成永生的裂殖体感染细胞系。高效感染性子孢子蜱源性稳定物可用于疫苗效力和攻毒试验以及疫苗开发。
