Senft A W, Weltman J K, Goldgraber M B, Egyud L G, Kuntz R E
Parasite Immunol. 1979 Spring;1(1):79-89. doi: 10.1111/j.1365-3024.1979.tb00697.x.
An acidic proteolytic enzyme which digests host haemoglobin can be isolated and purified from schistosomes. This small glycoprotein is an allergen which sensitizes the host, as shown by immediate hypersensitivity reactions. These are specific for either Schistosoma haematobium or S. mansoni and can be demonstrated by mast cell degranulation in mice or by intradermal skin tests in monkeys. Although high levels of total IgE may be found in acute and chronic schistosomiasis, there was no evident relationship between the worm burden in monkeys and immediate hypersensitivity reactions to either purified enzyme or crude schistosomal extracts. It is suggested that an in vivo correlation between worm burden and manifestations of the allergic response may be perturbed by high titres of non-specific IgE or other homocytotropic antibodies, thus accounting for false negative skin test reactions. Alternatively, a return to low or subnormal IgE levels may allow the restoration of the allergic response, giving rise to false positive reactions. Purified schistosomal antigens offer certain advantages over crude skin test preparations in terms of uniformity of antigen content, dosage and specificity. In addition, the enzyme may represent a species-specific tool for new immunochemical analyses of schistosomiasis.
一种能消化宿主血红蛋白的酸性蛋白水解酶可从血吸虫中分离纯化出来。这种小糖蛋白是一种变应原，可使宿主致敏，速发型超敏反应就表明了这一点。这些反应对埃及血吸虫或曼氏血吸虫具有特异性，可通过小鼠肥大细胞脱颗粒或猴子皮内皮肤试验来证实。虽然在急性和慢性血吸虫病中可发现高水平的总IgE，但猴子体内的虫负荷与对纯化酶或粗制血吸虫提取物的速发型超敏反应之间没有明显关系。有人认为，虫负荷与过敏反应表现之间的体内相关性可能会受到高滴度非特异性IgE或其他亲同种细胞抗体的干扰，从而导致皮肤试验反应出现假阴性。或者，IgE水平恢复到低水平或低于正常水平可能会使过敏反应恢复，从而产生假阳性反应。就抗原含量、剂量和特异性的一致性而言，纯化的血吸虫抗原比粗制皮肤试验制剂具有某些优势。此外，这种酶可能是用于血吸虫病新免疫化学分析的一种种属特异性工具。
