O'Donoghue P J, Friedhoff K T, Vizcaino O G, Weyreter H
Vet Parasitol. 1985 Jun;18(1):1-12. doi: 10.1016/0304-4017(85)90002-0.
Soluble extracts prepared from Babesia bigemina merozoites were tested for antigenicity in class-specific enzyme immunoassays currently being evaluated for the differential serodiagnosis of bovine babesiosis. Intact merozoites were harvested from erythrocytes from an experimentally-infected calf by controlled hypotonic lysis and differential ultra-centrifugation. The merozoites were disrupted by ultrasonication and a crude soluble extract obtained by ultracentrifugation. Fractionation of the crude extract on calibrated Sephadex G-200 columns consistently produced 4 fractions with molecular weights of 600, 40, 15 and 5 k (k = 10(3) daltons). Only the 600 and 15 k fractions proved to be antigenic when reacted against bovine immune sera. These fractions were incorporated into IgM- and IgG-specific enzyme immunoassays and used to determine the kinetics of the host-antibody responses to infection. The use of semi-defined antigens allowed assay standardization and good reproducibility of the results. A calf infected with a cryopreserved stabilate of B. bigemina originating from adult Boophilus microplus ticks developed a mild transient fever from 6-4 days post-infection (d.p.i.) and low parasitaemia levels from 7-16 d.p.i. IgG-antibodies first appeared at 7 d.p.i., peaked in intensity at 12 d.p.i. and then persisted at these levels until the end of the test period at 49 d.p.i. IgM-antibodies appeared at 7 d.p.i., peaked in intensity from 12-22 d.p.i., but then declined to low levels by 28 d.p.i. The importance of this transitory IgM-antibody response in the serodiagnosis of acute B. bigemina infections remains to be determined in clinical and field situations.
在目前正用于牛巴贝斯虫病鉴别血清诊断评估的类特异性酶免疫测定中，检测了从双芽巴贝斯虫裂殖子制备的可溶性提取物的抗原性。通过控制低渗裂解和差速超速离心，从实验感染小牛的红细胞中收获完整的裂殖子。裂殖子经超声破碎，并通过超速离心获得粗可溶性提取物。在经校准的葡聚糖凝胶G - 200柱上对粗提取物进行分级分离，始终产生分子量分别为600、40、15和5k（k = 10³道尔顿）的4个级分。当与牛免疫血清反应时，只有600k和15k的级分被证明具有抗原性。这些级分被纳入IgM和IgG特异性酶免疫测定中，并用于确定宿主对感染的抗体反应动力学。使用半确定抗原可实现测定标准化并使结果具有良好的可重复性。一头感染了源自成年微小牛蜱的双芽巴贝斯虫冷冻保存稳定株的小牛，在感染后6至4天出现轻度短暂发热，在感染后7至16天出现低寄生虫血症水平。IgG抗体在感染后7天首次出现，在感染后12天强度达到峰值，然后在这些水平持续到试验期结束时的49天。IgM抗体在感染后7天出现，在感染后12至22天强度达到峰值，但到感染后28天降至低水平。这种短暂的IgM抗体反应在急性双芽巴贝斯虫感染血清诊断中的重要性仍有待在临床和现场情况中确定。
