Jin L Z, Baidoo S K, Marquardt R R, Frohlich A A
Department of Animal Science, University of Manitoba, Winnipeg, Canada.
FEMS Immunol Med Microbiol. 1998 Aug;21(4):313-21. doi: 10.1111/j.1574-695X.1998.tb01179.x.
The objective of the study was to determine if the adhesion of E. coli K88 to piglet intestinal mucus could be inhibited in vitro by spray-dried egg-yolk anti-K88 antibodies. Binding of E. coli was monitored using a radioactive assay. Four 14+/-2-day-old healthy piglets were used for the preparation of mucus from the small intestine. Competition and displacement phenomena were investigated by incubating (a) egg-yolk antibodies and E. coli together prior to adding to the mucus and (b) E. coli and mucus, followed by egg-yolk antibodies. The results demonstrated that egg-yolk antibodies inhibited the adhesion of 3H-labeled local strain of hemolytic E. coli K88+ (E. coli K88+ MB) to piglet small intestinal mucus by 84.6-97.0% when the egg-yolk antibodies were diluted 10, 20, 40 or 100 times. The adhesion inhibiting effects of egg-yolk antibodies declined dramatically when the antibody dilution was more than 250-fold. A similar adhesion inhibiting effect was observed when egg-yolk antibodies were incubated with E. coli K88+ MB for 15, 30 and 60 min prior to the adhesion test. Egg-yolk antibodies when diluted 50- and 100-fold had a very strong inhibiting ability against E. coli K88+ MB at a concentration of 10(9) colony forming units (cfu) ml(-1) (adhesion was < 6%). However, dilution of 100 times for egg yolk antibodies was insufficient to inhibit the adhesion of E. coli K88+ MB to intestinal mucus when the concentration of E. coli K88+ MB was 10(10) cfu ml(-1). The displacement test indicated that there was no significant reduction in the adhesion of E. coli K88+ MB to the small intestinal mucus when egg-yolk antibodies were added after adhesion of the organism to the mucus. These studies demonstrate that anti-K88+ MB fimbriae antibodies from chicken egg-yolk when added to E. coli K88+ MB prevented their binding to receptors in the mucus isolated from the intestine of piglets.
本研究的目的是确定喷雾干燥的蛋黄抗K88抗体在体外是否能抑制大肠杆菌K88对仔猪肠黏液的黏附。使用放射性测定法监测大肠杆菌的结合情况。选用4头14±2日龄的健康仔猪制备小肠黏液。通过以下两种方式研究竞争和置换现象：(a) 在将蛋黄抗体和大肠杆菌加入黏液之前一起孵育；(b) 先将大肠杆菌与黏液孵育，然后加入蛋黄抗体。结果表明，当蛋黄抗体稀释10、20、40或100倍时，其对3H标记的溶血性大肠杆菌K88+本地菌株（大肠杆菌K88+ MB）黏附仔猪小肠黏液的抑制率为84.6% - 97.0%。当抗体稀释超过250倍时，蛋黄抗体的黏附抑制作用急剧下降。在黏附试验前，将蛋黄抗体与大肠杆菌K88+ MB孵育15、30和60分钟，也观察到了类似的黏附抑制效果。当浓度为10⁹菌落形成单位（cfu）/毫升时，稀释50倍和100倍的蛋黄抗体对大肠杆菌K88+ MB具有很强的抑制能力（黏附率<6%）。然而，当大肠杆菌K88+ MB的浓度为10¹⁰ cfu/毫升时，蛋黄抗体稀释100倍不足以抑制其对肠黏液的黏附。置换试验表明，在大肠杆菌黏附黏液后加入蛋黄抗体，大肠杆菌K88+ MB对小肠黏液的黏附没有显著降低。这些研究表明，来自鸡蛋黄的抗K88+ MB菌毛抗体在加入大肠杆菌K88+ MB后，可阻止其与从仔猪肠道分离的黏液中的受体结合。
