Onuma M, Kakuda T, Sugimoto C
Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
Comp Immunol Microbiol Infect Dis. 1998 Jul;21(3):165-77. doi: 10.1016/s0147-9571(98)00008-3.
Bovine piroplasmosis caused by Theileria sergenti is a major cause of economic loss in grazing cattle in Japan. We found that parasite stocks and isolates consist of genetically and antigenically mixed populations. To differentiate among parasite populations bearing 3 allelic forms of p32/34, an immunodominant piroplasmin surface protein, 3 sets of oligonucleotide primers were designed to amplify either of 3 alleles of T. sergenti/T. buffeli/T. orientalis by polymerase chain reaction (PCR). By using this allele-specific PCR, we found that in East Asia the majority of bovines infected with benign Theileria parasites harbored mixed parasite population. As a possible means of controlling Theileria sergenti infection, we produced 2 candidate vaccines; a bactilovirus expressed recombinant p32 and a synthetic peptide containing of Lys-Glu Lys (KEK) motif. Immunization with either of two candidates resulted in lower parasitemia and reduced the severity of clinical symptoms as compared to control calves.
由瑟氏泰勒虫引起的牛梨形虫病是日本放牧牛经济损失的主要原因。我们发现寄生虫种群和分离株由基因和抗原混合的群体组成。为了区分携带免疫优势梨形虫表面蛋白p32/34的3种等位基因形式的寄生虫群体，设计了3组寡核苷酸引物，通过聚合酶链反应（PCR）扩增瑟氏泰勒虫/水牛泰勒虫/东方泰勒虫的3个等位基因中的任何一个。通过使用这种等位基因特异性PCR，我们发现在东亚，大多数感染良性泰勒虫寄生虫的牛携带混合寄生虫群体。作为控制瑟氏泰勒虫感染的一种可能手段，我们生产了2种候选疫苗；一种杆状病毒表达的重组p32和一种含有赖氨酸-谷氨酸-赖氨酸（KEK）基序的合成肽。与对照小牛相比，用两种候选疫苗中的任何一种进行免疫都导致较低的寄生虫血症，并减轻了临床症状的严重程度。
