Jenkins D, Wakelin D
Department of Pathology, Queen's Medical Centre, University of Nottingham, UK.
Trans R Soc Trop Med Hyg. 1994 May-Jun;88(3):269-73. doi: 10.1016/0035-9203(94)90074-4.
The severity and consequences of human Trichuris infection vary widely. This may reflect differences in immune response. T. muris is a natural parasite of mice which provides a close, well defined, easily manipulated model for otherwise uninvestigatable aspects of this response. Normal mice reject the parasite in 3 weeks, but mice subjected to transient immunosuppression around the time of infection develop a persistent caecal infection. Sequential histopathological studies have shown that infected, normal mice develop a marked intraepithelial, mucosal, 'globule leucocyte' response, accompanied by low-level lymphocytic and histiocytic responses in the lamina propria. The reaction is maximal at 3 weeks and declines towards normal after rejection. Infected, immunosuppressed mice show a slower response with, by weeks 4 and 5, fewer 'globule leucocytes', but a chronic colitis comprising heavy, mixed, mucosal and submucosal inflammation and crypt damage accompanied by persistent parasite infection. The 'globule leucocyte' has been characterized by cytochemistry and electron microscopy as having a mast cell origin. This study, with other evidence, suggests that the replacement of a Th2 (allergic) T helper cell response by a Th1 (cell-mediated) response may result in increased severity and persistence of colitis in response to Trichuris infection.
人体鞭虫感染的严重程度和后果差异很大。这可能反映了免疫反应的差异。鼠鞭虫是小鼠的一种天然寄生虫，它为这种反应中其他难以研究的方面提供了一个密切、明确且易于操作的模型。正常小鼠在3周内排斥该寄生虫，但在感染时受到短暂免疫抑制的小鼠会发生持续的盲肠感染。连续的组织病理学研究表明，受感染的正常小鼠会出现明显的上皮内、黏膜“球样白细胞”反应，同时固有层伴有低水平的淋巴细胞和组织细胞反应。这种反应在3周时达到最大值，排斥后向正常水平下降。受感染的免疫抑制小鼠反应较慢，在第4周和第5周时，“球样白细胞”较少，但会出现慢性结肠炎，包括严重的、混合性的黏膜和黏膜下炎症以及隐窝损伤，并伴有持续的寄生虫感染。通过细胞化学和电子显微镜观察，“球样白细胞”的特征表明其起源于肥大细胞。这项研究以及其他证据表明，用Th1（细胞介导）反应替代Th2（过敏）辅助性T细胞反应可能会导致因鞭虫感染而引发的结肠炎的严重程度增加和持续时间延长。
