The enterobacterial common antigen (ECA) is a polysaccharide composed of polysaccharide repeats that are located in the outer membrane of almost all Enterobacteriaceae bacteria and has diverse biological functions. ECA is synthesized by the synergistic action of multiple genes that are present in clusters on the genome of Enterobacteriaceae bacteria, forming the ECA antigen gene cluster, an important virulence factor that plays a role in host invasion and survival of Enterobacteriaceae in vivo. ECA also plays an important role in the maintenance of the bacterial outer membrane permeability barrier, flagella gene expression, swarming motility, and bile salts resistance. In addition, ECALPS, anchored in the core region of bacterial lipopolysaccharide, is an important surface antigen for bacteria, stimulating high levels of antibody production in the host and could be a target for vaccine research. This review summarizes ECA purification, genes involved in ECA biosynthesis, its immunological characteristics, biological functions and clinical applications.
肠杆菌共同抗原 (Enterobacterial common antigen，ECA) 是由多糖重复单元组成的多聚糖，几乎表达于所有肠杆菌细菌外膜，具有生物学功能。ECA由多基因协同作用而合成，这些基因在肠杆菌细菌基因组上成簇存在，形成ECA抗原基因簇。ECA是重要的毒力因子，在肠杆菌细菌入侵宿主、体内存活等过程中有一定作用。同时，ECA在维持细菌外膜渗透屏障、鞭毛表达、群集运动及抗胆酸胆盐等方面也有重要作用。此外，锚定在细菌脂多糖核心区的ECALPS还是细菌重要的表面抗原，能激发宿主产生高水平抗体，可以作为疫苗研究的靶点。结合笔者的研究，文中对ECA纯化、基因结构和合成、免疫特性、生物学功能及应用等方面进行了综述。.
Keywords: Enterobacteriaceae; biosynthesis; enterobacterial common antigen (ECA); immunological characteristics; virulence.