Shkap V, Pipano E
Kimron Veterinary Institute, P.O. Box 12, Bet Dagan, 50250, Israel.
Ann N Y Acad Sci. 2000;916:154-71. doi: 10.1111/j.1749-6632.2000.tb05286.x.
The major economically important tick-borne diseases of cattle are theileriosis, babesiosis, anaplasmosis, and cowdriosis. Culture-derived attenuated schizonts of Theileria annulata have proved to be safe for all types of cattle and they protect against tick-borne theileriosis. T. parva was also successfully grown in vitro; however, inoculation of cattle with allogeneic schizont-infected cells resulted in rejection and destruction of the parasites together with the host cells. The number of schizont-infected cells needed for immunization is greater than for T. annulata theileriosis. Culture-propagated Babesia bovis and B. bigemina were used for large scale vaccination in the field. An avirulent population of Babesia spp. was obtained by in vitro cloning; inoculation of cattle did not induce clinical babesiosis, but produced specific antibodies. Culture-derived exoantigens of Babesia spp. proved to be completely safe for cattle, however, they conferred less protection than live parasites. Cell-cultured Cowdria ruminantium was highly infective for susceptible animals but, attenuated in vitro, could offer a potential source for vaccination. Anaplasma marginale, successfully grown in tick cell culture, may be developed for vaccines. Factors that should be considered in the developing of vaccines against tick-borne diseases include: the protective immune response to the pathogenic parasite developmental stages, virulence, immunological strain differences, and antigenic variations in cattle and in culture.
牛的主要经济上重要的蜱传疾病是泰勒虫病、巴贝斯虫病、无浆体病和考德里氏体病。已证明源自培养物的环形泰勒虫减毒裂殖体对所有类型的牛都是安全的,并且能预防蜱传泰勒虫病。微小泰勒虫也成功地在体外培养;然而,用同种裂殖体感染的细胞接种牛会导致寄生虫与宿主细胞一起被排斥和破坏。免疫所需的裂殖体感染细胞数量比环形泰勒虫病更多。在田间,通过培养繁殖的牛巴贝斯虫和双芽巴贝斯虫用于大规模疫苗接种。通过体外克隆获得了无毒力的巴贝斯虫种群;接种牛不会诱发临床巴贝斯虫病,但会产生特异性抗体。源自培养物的巴贝斯虫外抗原已证明对牛完全安全,然而,它们提供的保护比活寄生虫少。细胞培养的反刍兽考德里氏体对易感动物具有高度传染性,但在体外减毒后,可能成为疫苗的潜在来源。在蜱传疾病疫苗开发中应考虑的因素包括:对致病性寄生虫发育阶段的保护性免疫反应、毒力、免疫菌株差异以及牛和培养物中的抗原变异。