Jones S R
Department of Fisheries and Oceans, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, V9R 5K6, Canada.
Dev Comp Immunol. 2001 Oct-Dec;25(8-9):841-52. doi: 10.1016/s0145-305x(01)00039-8.
Parasitic infections in teleost fish are limited by constitutive innate defence mechanisms that render the host refractory or reduce the severity of infection. Controlled challenge trials using naive animals provide indirect evidence of innate immunity as well as identifying the host range or specificity of a parasite, often when specific details of defence mechanism(s) are lacking. Examples of parasites for which innate immunity may be inferred from cross-infectivity studies include Gyrodactylus spp., Lepeophtheirus salmonis, Cryptobia spp., Trypanosoma spp., Ceratomyxa shasta, Myxobolus cerebralis and Kudoa thyrsites. Recent studies however, have begun to clarify the relative roles of innate and acquired immunity against parasitic infection in teleosts by recognizing the presence and significance of specific innate effector mechanisms. The physico-chemical characeristics of skin mucus, the presence of bioactive substances including lysozyme, complement, C-reactive protein, haemolysins and lectins and the epidermal migration of inflammatory cells and their secretions may affect the establishment and proliferation of ectoparasitic copepods, ciliates or monogenea. Similarly in refractory species, haematozoic parasites are lysed via the alternative complement pathway and in susceptible and refractory hosts, protease inhibitors associated with the plasma neutralize proteolytic virulence factors. Detailed knowledge of innate resistance mechanisms against histiozoic parasites are lacking although non-specific cytotoxic lymphoid cells and macrophages probably play a role. The demonstration in certain disease models that innate resistance traits are under genetic control and may be inherited in a simple Mendelian fashion suggests opportunities for selective breeding for resistance against parasitic disease. Beyond a small number of well-described models however, research programs focussing on innate immunity against parasites in fish are lacking. Given the relative importance of innate immunity in fish, particularly as disease losses continue to have an economic impact in aquaculture, this area deserves considerable attention.
硬骨鱼中的寄生虫感染受到组成性固有防御机制的限制，这些机制使宿主具有抵抗力或降低感染的严重程度。使用未感染过的动物进行的对照攻毒试验提供了固有免疫的间接证据，同时也确定了寄生虫的宿主范围或特异性，这通常是在缺乏防御机制具体细节的情况下进行的。可以从交叉感染研究中推断出固有免疫的寄生虫例子包括三代虫属、鲑鱼虱、隐鞭虫属、锥虫属、脑粘体虫、脑碘泡虫和库道虫。然而，最近的研究开始通过认识到特定固有效应机制的存在及其重要性，来阐明硬骨鱼中固有免疫和获得性免疫在抵抗寄生虫感染方面的相对作用。皮肤黏液的物理化学特性、包括溶菌酶、补体、C反应蛋白、溶血素和凝集素在内的生物活性物质的存在，以及炎症细胞及其分泌物的表皮迁移，可能会影响体外寄生桡足类、纤毛虫或单殖吸虫的定殖和增殖。同样，在具有抵抗力的物种中，血寄生性寄生虫通过替代补体途径被裂解，而在易感和有抵抗力的宿主中，与血浆相关的蛋白酶抑制剂会中和蛋白水解性毒力因子。尽管非特异性细胞毒性淋巴细胞和巨噬细胞可能发挥作用，但目前仍缺乏针对组织内寄生性寄生虫的固有抵抗机制的详细知识。在某些疾病模型中，固有抗性特征受遗传控制且可能以简单的孟德尔方式遗传，这表明通过选择性育种提高对寄生虫病的抵抗力具有可能性。然而，除了少数描述详尽的模型外，针对鱼类抵抗寄生虫的固有免疫的研究项目还很匮乏。鉴于固有免疫在鱼类中的相对重要性，尤其是疾病损失持续对水产养殖造成经济影响，这一领域值得给予相当多的关注。
