LPS由类脂A、核心多糖(分为外核心和内核心)和O抗原三部分组成,依据O抗原的外核心多糖的差异,大肠杆菌(Escherichiacoli)LPS被分为5种类型,分别为R1、R2、R3、R4、K12[2-4],并且外核心多糖的差异与大肠杆菌的致病性等生物学特性有关联[5-7]。因此,对LPS核心型的研究成为研究大肠杆菌致病性以及新型疫苗的新方向。禽致病性大肠杆菌(Avian Pathogenic Escherichiacoli,APEC)可引起鸡、鸭及其他禽类的肠道外疾病,严重制 LPS consists of lipid A, core polysaccharides (divided into outer core and inner core) and O antigen. According to the difference of outer core polysaccharide of O antigen, LPS of Escherichia coli is divided into five types, which are R1 , R2, R3, R4, K12 [2-4], and the difference of outer core polysaccharides is related to the biological characteristics of E. coli such as pathogenicity [5-7]. Therefore, the study of LPS core type has become a new direction for studying the pathogenicity of E. coli and new vaccines. Avian Pathogenic Escherichia coli (APEC) can cause parenteral diseases in chickens, ducks and other birds, severe