Vieira L Q, Gazzinelli G, Kusel J R, De Souza C P, Colley D G
Parasite Immunol. 1986 Jul;8(4):333-43. doi: 10.1111/j.1365-3024.1986.tb00850.x.
During in vitro transformation of Schistosoma mansoni cercariae into schistosomula, surface and glandular materials are released into the culture medium. Extracts of these materials, termed cercarial released extracts 1 and 2 (CRE-1 and CRE-2), were analysed and found to consist primarily of protein and carbohydrate at ratios of 5:1 (CRE-1) and 7:1 (CRE-2). It was observed that inclusion of either CRE-1 or CRE-2 in cultures of human peripheral blood mononuclear cells (PBMN) led to decreased cell proliferation. This was true whether the cells were resting, control cultures or were stimulated with either phytohaemagglutinin or an antigenic preparation from adult S. mansoni worms. The inhibition was equally effective with PBMN of patients with active schistosomal infection or PBMN from uninfected individuals. Since these materials are released spontaneously during cercarial-to-schistosomular transformation they may have a putative immunosuppressive effect in decreasing antischistosomular activities early after cercarial penetration.
在曼氏血吸虫尾蚴体外转化为童虫的过程中，表面物质和腺体物质会释放到培养基中。对这些物质的提取物（称为尾蚴释放提取物1和2，即CRE - 1和CRE - 2）进行分析后发现，其主要成分是蛋白质和碳水化合物，比例分别为5:1（CRE - 1）和7:1（CRE - 2）。据观察，在人外周血单核细胞（PBMN）培养物中加入CRE - 1或CRE - 2都会导致细胞增殖减少。无论细胞是处于静息状态、作为对照培养物，还是用植物血凝素或来自曼氏血吸虫成虫的抗原制剂刺激，都是如此。这种抑制作用对活动性血吸虫感染患者的PBMN或未感染个体的PBMN同样有效。由于这些物质是在尾蚴向童虫转化过程中自发释放的，它们可能在尾蚴穿透后早期对降低抗血吸虫活动具有假定的免疫抑制作用。
