大菱鲆CD55负调控补体激活及其广谱细菌结合能力实验数据

CD55蛋白在哺乳动物中是一种补体调控因子，但其在鱼类中的功能未知。本研究探索了大菱鲆（Scophthalmus maximus）CD55（SmCD55）蛋白的功能。结果表明，SmCD55蛋白由344个氨基酸残基构成，含有一个N端信号肽和3个补体调控蛋白（CCP）功能域。SmCD55基因在大菱鲆多种组织中均有表达，其中，在肌肉中表达量最低，在脑组织的表达量最高。通过原核表达获得了重组的SmCD55（rSmCD55）蛋白，发现rSmCD55蛋白能够抑制大菱鲆血清的溶血活性和杀菌活性，表明其负调控补体系统的激活。此外，本研究还发现rSmCD55蛋白可以结合包括重要水产病原菌Edwardsiella tarda、Pseudomonas fluorescens、Vibrio anguillarum、Vibrio harveyi和Streptococcus iniae在内的多种细菌，其中与V. harveyi的结合能力最强。以上这些研究结果丰富了鱼类补体系统的理论知识，加深了对鱼类补体激活调控的了解。CD55 is a complement regulatory factor in mammals, yet its function in fish remains unclear. This study investigated the function of CD55 (SmCD55) in the turbot (Scophthalmus maximus). The results showed that SmCD55 consists of 344 amino acid residues, containing one N-terminal signal peptide and three complement control protein (CCP) domains. The SmCD55 gene is ubiquitously expressed in various tissues of turbot, with the lowest expression level in muscle and the highest in brain tissue. Recombinant SmCD55 (rSmCD55) protein was obtained via prokaryotic expression, and it was found that rSmCD55 could inhibit the hemolytic and bactericidal activities of turbot serum, indicating that it negatively regulates the activation of the complement system. Furthermore, this study found that rSmCD55 can bind to multiple bacteria including important aquatic pathogenic bacteria such as Edwardsiella tarda, Pseudomonas fluorescens, Vibrio anguillarum, Vibrio harveyi, and Streptococcus iniae, with the strongest binding affinity towards V. harveyi. These research findings enrich the theoretical knowledge of the fish complement system and deepen the understanding of the regulation of fish complement activation.