表达K_(99)和F_(41)双价保护性抗原工程菌株的构建及免疫效果研究

本文应用基因重组技术,将引起犊牛、羔羊大肠菌腹泻的主要致病因子的保护性抗原基因K_(99)和F_(41)从野生株先分别克隆,然后组构成同时表达两种抗原的工程菌疫苗候选株。研究了该工程菌表达的两种抗原的性质,影响表达的条件。同时经过免疫怀孕母羊然后进行人工攻毒及田间大面积免疫羊群,证明该工程疫苗候选株能有效诱发机体的免疫应答,对羔羊有显著地保护作用。     

RECOMBINANT BIVALENT LIVK VACCINES AGAINST NEONATAL COLIBACILLOSIS IN PIGLETS

The genes of colonization factor K88 and avirulent heat-labile enterotoxin LT A-B+ of enterotoxigenic E. coli (ETEC) have been ligated, and a vaccine strain containing recombinant plasmid that efficiently expresses two antigens has been obtained. Using the activity of β-galactosidase as a selection marker instead of drug resistance, another bivalent vaceire strain with the same expression level has also been constructed. The vaccinestrains have no toxicity and do not cause any adverse reactions. In chellenge study and field trials, a high degree of protection from colibacillosis was afforded to piglets when their dams were immunized orally or parenterally. Practice of bivalent live vaccines including colonization factor and enterotoxin antigens and without antibiotic resistance gene shows effective.     

预防新生仔猪大肠菌性腹泻的双价工程菌苗

本文应用遗传工程技术,将猪毒素源性大肠杆菌(ETEC)的粘附素K88与无毒肠毒索LTA~-B~+基因组建成能同时表达两种抗原成分的菌苗;进一步去除抗药性基因,以β-半乳糖苷酶活性作为筛选标记,得到表达水平相似的双价菌苗。菌苗无毒安全,能有效地激发机体的免疫应答,经过人工攻毒试验与田间试验,首次报道了K88与LT协同免疫对大肠菌性腹泻的显著保护力,以及无抗药性基因菌苗在实际中的应用。