Hoyle D V, Dalton J P, Chase-Topping M, Taylor D W
Centre for Tropical Veterinary Medicine, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, Scotland, UK.
Vet Parasitol. 2003 Jan 20;111(1):65-82. doi: 10.1016/s0304-4017(02)00326-6.
In this study we examined whether juvenile liver flukes are capable of stimulating protective immune responses in cattle. Four experimental groups of cattle were studied as follows: group A, a positive control, received a primary infection on day 0 and a secondary infection 28 days later; group B also received two infections but the primary infection was terminated by drug treatment on day 5; group C, received infections on days 0, 5 and 10 which were terminated by drug treatments on days 1, 6 and 11 and then a secondary infection on day 28; group D received an infection only on day 28. Juvenile flukes appear to induce protective responses because: (a) group B animals had significantly lower levels of gamma-GT (P<0.05) than group D; (b) both groups B and C exhibited lower parenchymal phase GLDH levels (P=0.006 and 0.041, respectively); and (c) both groups B and C had lower secondary phase eosinophilia (P=0.002 and 0.02, respectively) than those in group D. Sera taken from groups A-C contained antibodies reacting to a variety of proteins in adult fluke somatic antigen and excretory-secretory preparations, particularly to proteins of 52-60, 68-72 and 82-96 kDa. After secondary challenge the antibody responses of group A to these proteins declined while reactivity to proteins of 28-30 kDa increased. Antibody responses to the 28-30 kDa proteins were not detected in groups B-D until 3 weeks later than those observed in group A. Antibody responses to Fasciola hepatica cathepsin L proteases, which are known to induce protection, were monophasic, of the IgG1 isotype only and were not observed prior to secondary challenge in any of the four groups. In contrast, the response to another protective antigen fraction, a high molecular sized haem protein, was of a mixed IgG1/IgG2 nature and was detected within 14 days of primary infection. However, no significant difference in antibody titres to either protein preparation was observed after the secondary infection when groups B and C were compared to group D.
在本研究中，我们检测了幼年肝片吸虫是否能够刺激牛产生保护性免疫反应。对四组实验牛进行了如下研究：A组为阳性对照，在第0天接受初次感染，并在28天后接受二次感染；B组也接受两次感染，但初次感染在第5天通过药物治疗终止；C组在第0、5和10天接受感染，并在第1、6和11天通过药物治疗终止，然后在第28天接受二次感染；D组仅在第28天接受感染。幼年吸虫似乎能诱导保护性反应，原因如下：(a) B组动物的γ-GT水平显著低于D组(P<0.05)；(b) B组和C组的实质期谷草转氨酶水平均较低(P分别为0.006和0.041)；(c) B组和C组的二次期嗜酸性粒细胞增多程度均低于D组(P分别为0.002和0.02)。从A-C组采集的血清中含有与成年吸虫体抗原和排泄-分泌制剂中多种蛋白质发生反应的抗体，特别是与52-60、68-72和82-96 kDa的蛋白质发生反应。二次攻击后，A组对这些蛋白质的抗体反应下降，而对28-30 kDa蛋白质的反应性增加。B-D组直到比A组观察到的时间晚3周才检测到对28-30 kDa蛋白质的抗体反应。对已知能诱导保护作用的肝片吸虫组织蛋白酶L蛋白酶的抗体反应是单相的，仅为IgG1同种型，在四组中的任何一组二次攻击前均未观察到。相比之下，对另一种保护性抗原组分，即高分子量血红素蛋白的反应是IgG1/IgG2混合性质的，在初次感染后14天内即可检测到。然而，二次感染后，将B组和C组与D组进行比较时，对这两种蛋白质制剂的抗体滴度没有显著差异。
