Munderloh U G, Blouin E F, Kocan K M, Ge N L, Edwards W L, Kurtti T J
Department of Entomology, University of Minnesota, St. Paul 55108, USA.
J Med Entomol. 1996 Jul;33(4):656-64. doi: 10.1093/jmedent/33.4.656.
Anaplasma marginale is a tick-borne rickettsia that causes bovine anaplasmosis worldwide. Despite its importance, A. marginale has thus far not been established in a continuous culture system. We have propagated A. marginale continuously for the 1st time in a tick cell line derived from the black-legged tick, Ixodes scapularis Say, using infected bovine blood as the inoculum. Erythrocytic stages invaded the tick cells and multiplied in membrane-lined vacuoles to form colonies typical of those observed in naturally infected ticks as demonstrated by light and electron microscopy. The rickettsiae have been passaged serially for 3 yr and have been cryopreserved in liquid nitrogen. Antigens present in A. marginale from tick cell culture were recognized by bovine immune serum against the blood stages of A. marginale. A. marginale grown in this tick cell line was infective for calves, and male ticks fed on the calves transmitted A. marginale to a susceptible calf. The ability to culture A. marginale removes a major impediment to the study of Anaplasma biology in vitro, and will enhance development of vaccines and diagnostic tests.
边缘无形体是一种通过蜱传播的立克次氏体，可在全球范围内引起牛无浆体病。尽管其具有重要性，但迄今为止边缘无形体尚未在连续培养系统中得以建立。我们首次使用感染的牛血作为接种物，在源自肩突硬蜱（Ixodes scapularis Say）的蜱细胞系中连续繁殖边缘无形体。红细胞阶段侵入蜱细胞，并在膜包被的液泡中增殖形成菌落，这与在自然感染蜱中观察到的菌落典型特征一致，光学显微镜和电子显微镜均证实了这一点。立克次氏体已连续传代3年，并已保存在液氮中。蜱细胞培养的边缘无形体中的抗原可被针对边缘无形体血液阶段的牛免疫血清识别。在此蜱细胞系中生长的边缘无形体对犊牛具有感染性，以犊牛为食的雄蜱将边缘无形体传播给了一头易感犊牛。培养边缘无形体的能力消除了体外研究无形体生物学的一个主要障碍，并将促进疫苗和诊断测试的开发。
