Unidad de Trematodiasis, Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
Parasite Immunol. 2010 Jan;32(1):20-8. doi: 10.1111/j.1365-3024.2009.01152.x.
Schistosoma mansoni cathepsin B (Sm31) is a major antigen from adult worms that circulates in the blood of infected patients (Li et al., Parasitol Res 1996; 82: 14-18). An analysis of the Sm31 sequence (Klinkert et al., Mol Biochem Parasitol 1989; 33: 113-122) allowed the prediction of seven hydrophilic regions that were confirmed to be exposed on the surface of a 3D model of Sm31; the species specificity of these regions was checked using BLAST analysis. The corresponding peptides were chemically synthesized in polymerazible forms using the t-Boc technique. Rabbits developed a high humoral response against these peptides as tested by a multiple antigen blot assay; it recognized native Sm31 in crude S. mansoni extracts and as circulating antigen in sera of S. mansoni-infected patients by western blot. Relevant antigenic determinants were located at the N- and C-terminus sequences. Antibodies against these regions recognized the native enzyme in an ELISA-like assay called cysteine protease immuno assay in which the immunocaptured enzyme was revealed by the intrinsic cathepsin B hydrolytic activity of Sm31. The method successfully and specifically detected Sm31 in sera of infected individuals, most of them (83.3%) with light infections, offering a rationale for the development of parasite enzyme capture assays using anti-synthetic peptide antibodies for possible use in the diagnosis of schistoso,iasis.
曼氏血吸虫组织蛋白酶 B（Sm31）是一种来自成虫的主要抗原，存在于感染患者的血液中（Li 等人，Parasitol Res 1996；82: 14-18）。对 Sm31 序列的分析（Klinkert 等人，Mol Biochem Parasitol 1989；33: 113-122）允许预测七个亲水区域，这些区域被证实暴露在 Sm31 的三维模型表面上；使用 BLAST 分析检查了这些区域的物种特异性。使用 t-Boc 技术以聚合物形式化学合成了相应的肽。通过多重抗原印迹分析测试，兔子对这些肽产生了高体液反应；它在粗制曼氏血吸虫提取物中识别天然 Sm31，并通过 Western blot 在曼氏血吸虫感染患者的血清中识别循环抗原。相关的抗原决定簇位于 N-和 C-末端序列。针对这些区域的抗体在称为半胱氨酸蛋白酶免疫测定的 ELISA 样测定中识别天然酶，其中免疫捕获的酶通过 Sm31 的内在组织蛋白酶 B 水解活性来揭示。该方法成功且特异性地检测到感染个体血清中的 Sm31，其中大多数（83.3%）为轻度感染，为使用抗合成肽抗体开发寄生虫酶捕获测定提供了依据，以便可能用于诊断血吸虫病。
