McKeever Declan J
Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, UK.
Trends Parasitol. 2009 Jun;25(6):269-76. doi: 10.1016/j.pt.2009.03.005. Epub 2009 May 5.
Theileria parva and Theileria annulata are tick-borne parasites of cattle that infect and transform leukocytes, causing severe and often fatal parasitic leukoses. Both species provoke strong immunity against subsequent infection. However, considerable diversity is observed in field populations of each parasite and protection is only assured against homologous challenge. The life cycles of these parasites are complex and involve prolonged exposure to host and vector defence mechanisms. Although the relevant vector mechanisms are poorly defined, protective responses of cattle seem to be tightly focused and variable in their specificity between individuals. This review considers whether bovine immunity acts as a driver for diversity in T. parva and T. annulata and explores other factors that might underlie genetic variation in these parasites.
小泰勒虫和环形泰勒虫是牛的蜱传寄生虫，它们感染并转化白细胞，导致严重且往往致命的寄生性白血病。这两个物种都能激发针对后续感染的强大免疫力。然而，在每种寄生虫的野外种群中都观察到了相当大的多样性，并且只有针对同源攻击才能确保保护。这些寄生虫的生命周期很复杂，需要长时间暴露于宿主和媒介的防御机制。尽管相关的媒介机制尚不明确，但牛的保护性反应似乎高度集中，且个体之间的特异性存在差异。本文综述探讨了牛的免疫力是否是小泰勒虫和环形泰勒虫多样性的驱动因素，并探究了这些寄生虫遗传变异可能的其他潜在因素。
