抗大肠杆菌肠毒素卵黄抗体的制备和鉴定

Preparation and identification of egg yolk antibodies against Escherichia coli enterotoxin

为了研究用不耐热肠毒素B亚基(LTB)和耐热肠毒素(STa)的融合蛋白制备鸡卵黄抗体的方法及其中和作用,试验将LTB和STa的编码基因串联并在大肠杆菌中表达获得了重组蛋白,以重组蛋白为免疫原免疫8月龄海兰蛋鸡制备了卵黄抗体,分别用兔肠段结扎试验和乳鼠灌胃试验进行了卵黄抗体对不耐热肠毒素(LT)和STa的体内中和试验。结果表明:用LTB和STa融合蛋白免疫产蛋鸡可诱导产生抗LTB和STa的卵黄抗体,其中抗LTB效价最高可达1∶8 647,抗STa效价最高可达1∶768;卵黄抗体对LT和STa均有中和作用。说明用融合蛋白作为免疫原制备的卵黄抗体具有抗LT和STa的生物学活性,对仔猪大肠杆菌性腹泻的临床治疗有潜在的应用价值。

To study the method of preparing the egg yolk antibodies using the fusion protein of heat - labile enterotoxin B subunit （ LTB ） and heat - stable enterotoxin （STa） and their neutralization, the coding genes of LTB and STa were connected in series and expressed in Escherichia coli to obtain the recombinant protein. The egg yolk antibodies were prepared through immunizing the eight - month - old Hyline laying hens with the recombinant protein ; the neutralization tests in vivo against heat - labile enterotoxin （LT） and STa, were conducted by rabbit ligated intesti- nal loops and intragastfic administration to sukling mice, respectively. The results showed that the egg yolk antibodies against LTB and STa were induced by the fusion protein of LTB and STa, in which the highest titer of the antibodies against LTB reached 1：8 647 and the highest titer of the antibodies against STa reached 1：768 ; the egg yolk antibodies had neutralizing effects against LT and STa. The results indicate that the egg yolk antibodies which prepared with fusion protein as an immunogen, have the biological activity against LT and STa, and have the potential ap- plication value in the clinical treatment of Escherichia coil diarrhea in piglets.