Kocan K M, Blouin E F, Palmer G H, Eriks I S, Edwards W L
Department of Veterinary Pathology, College of Veterinary Medicine Oklahoma State University, Stillwater 74078, USA.
Ann N Y Acad Sci. 1996 Jul 23;791:157-65. doi: 10.1111/j.1749-6632.1996.tb53522.x.
Anaplasma marginale is a rickettsia transmitted by ticks that invades and multiplies in bovine erythrocytes causing the disease anaplasmosis. A complex developmental cycle occurs within ticks that begins in midgut cells, with subsequent infection in gut muscle cells. Final development occurs in salivary glands from where the rickettsia is transmitted to the vertebrate host. At each site of development, A. marginale multiplies within membrane-bound inclusions. Attempts to control anaplasmosis have focused on cattle and have included immunization and prophylactic treatment with tetracyclines. New strategies for control of anaplasmosis are being focused on the tick vector. Development of vaccines against hemoparasites in ticks may be feasible because vertebrate host immunoglobulins appear to cross the midgut epithelium of invertebrates and enter the hemolymph without breakdown. We tested the effect of A. marginale antibodies ingested by ticks with the bloodmeal on infections in ticks. Cattle were immunized with purified outer membrane proteins of erythrocytic-derived parasites. Infections in ticks exposed to the immunized cattle were determined using an Anaplasma-specific DNA probe, light and electron microscopy, and tick transmission studies. Vaccine-derived antibodies did not appear to affect the development and transmission of A. marginale in ticks. Further studies are needed to determine if bovine antibodies remain intact within ticks and whether the tick stage of A. marginale has unique surface antigens from the erythrocytic stage.
边缘无形体是一种由蜱传播的立克次氏体，它侵入牛红细胞并在其中繁殖，引发无形体病。在蜱体内会发生一个复杂的发育周期，始于中肠细胞，随后感染肠肌细胞。最终发育发生在唾液腺，立克次氏体从这里传播到脊椎动物宿主。在每个发育位点，边缘无形体都在膜结合的包涵体内繁殖。控制无形体病的努力主要集中在牛身上，包括免疫和用四环素进行预防性治疗。控制无形体病的新策略正聚焦于蜱媒。开发针对蜱体内血寄生虫的疫苗可能是可行的，因为脊椎动物宿主免疫球蛋白似乎能穿过无脊椎动物的中肠上皮并进入血淋巴而不被分解。我们测试了蜱通过血餐摄取的边缘无形体抗体对蜱感染的影响。用红细胞源性寄生虫的纯化外膜蛋白对牛进行免疫。使用无形体特异性DNA探针、光学和电子显微镜以及蜱传播研究来确定暴露于免疫牛的蜱的感染情况。疫苗产生的抗体似乎不影响边缘无形体在蜱体内的发育和传播。需要进一步研究以确定牛抗体在蜱体内是否保持完整，以及边缘无形体的蜱阶段是否具有与红细胞阶段独特的表面抗原。
