Characterization of immune receptors in fish

免疫系统最重要的作用之一是防止受感染或受损的宿主细胞的生长。例如，被病毒感染的细胞或在肿瘤中发现的细胞被识别为异常，并被称为淋巴细胞的特化白色血细胞有效地破坏。如果没有这种识别系统，病毒感染和恶性肿瘤就会扩散到全身。因此，了解淋巴细胞如何决定细胞是否应该被杀死或幸免一直是多年来深入研究的焦点。这些实验表明，淋巴细胞使用细胞表面蛋白质的复杂网络来调查周围细胞的感染或损伤迹象。这些蛋白质（或受体）通常识别邻近细胞表面上存在的共同蛋白质，一旦细胞被癌症感染或转化，该蛋白质就会减少或丢失。这种蛋白质的丢失将这些细胞标记为异常，随后将其作为破坏的目标。这种基本机制在人类和小鼠中得到了很好的研究，但在其他遇到病毒并必须限制癌细胞扩散的脊椎动物物种中却知之甚少。因此，我有兴趣了解鱼类免疫细胞如何介导这些重要的免疫反应。鱼类淋巴细胞的功能与哺乳动物淋巴细胞相似，但缺乏对调节这些反应的免疫受体的鉴定和表征。最近，我发现了一个新的免疫受体家族在海峡鲶鱼，是相关的受体在哺乳动物参与免疫监视病毒感染或癌细胞。这些独特的鲶鱼受体的表征代表了研究先天免疫调节受体的进化和功能的极好机会。这不仅将增强我们目前对鱼类免疫反应的理解，而且还将提供有关整个脊椎动物先天免疫受体保护机制的重要信息。鲶鱼也是一种有价值的水产养殖作物，进一步了解其抗病毒和抗肿瘤防御机制将有助于改善水产养殖实践中的鱼类健康。

One of the most important roles of the immune system is to prevent the growth of infected or damaged host cells. For example, cells infected with viruses or those found within tumors are recognized as abnormal and efficiently destroyed by specialized white blood cells called lymphocytes. Without this recognition system viral infections and malignant tumors would spread throughout the body. Therefore, understanding how lymphocytes determine if a cell should be killed or spared has been the focus of intense research over the years. These experiments demonstrated that lymphocytes use an intricate network of cell surface proteins to survey surrounding cells for signs of infection or damage. These proteins (or receptors) often recognize a common protein presented on the surface of neighbouring cells, which is reduced or lost once a cell becomes infected or transformed by cancer. Loss of this protein then marks these cells as abnormal and they are subsequently targeted for destruction. This essential mechanism is well studied in humans and mice but little is known in other vertebrate species that encounter viruses and must limit the spread of cancerous cells. Therefore, I am interested in understanding how fish immune cells mediate these important immune responses. Fish lymphocytes function in a similar manner as their mammalian counterparts but the identification and characterization of the immune receptors that regulate these responses is lacking. Recently, I identified a new family of immune receptors in the channel catfish that are related to receptors in mammals involved in immune surveillance for virally infected or cancerous cells. Characterization of these unique catfish receptors represents an excellent opportunity to study the evolution and function(s) of innate immunoregulatory receptors. This will not only enhance our present understanding of fish immune responses but will also provide important information regarding innate immune receptor protection mechanisms throughout vertebrates. Catfish are also a valuable aquaculture crop and a further understanding of their anti-viral and anti-tumor defense mechanisms will allow for improvements of fish health in aquaculture practices.