Watthanakulpanich Dorn, Smith Huw V, Hobbs Glyn, Whalley Anthony J, Billington David
School of Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK.
Acta Trop. 2008 May;106(2):90-5. doi: 10.1016/j.actatropica.2008.01.008. Epub 2008 Feb 7.
A major problem in the serodiagnosis of human toxocariasis in tropical countries is cross-reaction with antibodies to other helminthic diseases and a lack of sensitivity. The majority of tests currently available use total IgG and, in this study, the use of peroxidase-conjugated anti-human IgG subclass antibodies (IgG1-4) was compared with total IgG for the diagnosis of human toxocariasis by using Toxocara excretory-secretory (TES) antigens in an enzyme-linked immunosorbent assay (ELISA) format. All four IgG subclass antibodies gave approximately 10-fold increases in optical density (OD) values for 50 toxocariasis patients compared to 29 healthy normals; this was significantly greater than the approximate doubling of OD values seen in the total IgG-ELISA format. IgG2 gave by far the greatest sensitivity (values: IgG, 50%; IgG1, 60%; IgG2, 98%; IgG3, 78%; IgG4, 64%). Significant cross-reactivity using all IgG subclasses in the TES ELISA was seen with 141 serum samples from patients with 10 other helminthic infections. However, IgG3 gave the best specificity (values: IgG, 73%; IgG1, 76%; IgG2, 71%; IgG3, 81%; IgG4, 71%). Thus, of the IgG subclass antibodies, IgG2 appeared best and employing this subclass can improve the serodiagnosis of human toxocariasis since it recognises carbohydrate epitopes of TES antigens.
在热带国家，人类弓蛔虫病血清学诊断中的一个主要问题是与其他蠕虫病抗体的交叉反应以及缺乏敏感性。目前大多数可用检测使用总IgG，在本研究中，通过酶联免疫吸附测定（ELISA）形式，将过氧化物酶偶联的抗人IgG亚类抗体（IgG1 - 4）与总IgG用于人类弓蛔虫病诊断进行比较，使用弓蛔虫排泄分泌（TES）抗原。与29名健康正常人相比，50名弓蛔虫病患者的所有四种IgG亚类抗体的光密度（OD）值均增加了约10倍；这明显大于总IgG - ELISA形式中OD值约两倍的增加。IgG2的敏感性最高（数值：IgG，50%；IgG1，60%；IgG2，98%；IgG3，78%；IgG4，64%）。在TES ELISA中，使用所有IgG亚类对141份来自患有其他10种蠕虫感染患者的血清样本观察到显著的交叉反应。然而，IgG3的特异性最佳（数值：IgG，73%；IgG1，76%；IgG2，71%；IgG3，81%；IgG4，71%）。因此，在IgG亚类抗体中，IgG2似乎最佳，采用该亚类可改善人类弓蛔虫病的血清学诊断，因为它识别TES抗原的碳水化合物表位。
