Whipp S C
National Animal Disease Center, U.S. Department of Agriculture, Ames, Iowa 50010.
Infect Immun. 1990 Apr;58(4):930-4. doi: 10.1128/iai.58.4.930-934.1990.
The Escherichia coli heat-stable enterotoxin STb is the most prevalent toxin associated with diarrheagenic isolates of porcine origin. This report demonstrates that when endogenous protease activity was blocked with soybean trypsin inhibitor, STb evoked a dose-dependent secretory response in infant mice and jejunal loops of rats. Infant mice were much less sensitive to STb than rats were. The response of rat jejunal loops to STb was linearly related to the log of the dose of STb through 10 twofold dilutions. The anterior 25% of the jejunum was less sensitive than was the remainder of the gut. An incubation period of 2.5 h provided a maximal response. The linear response to STb in rats could be used as a bioassay.
大肠杆菌热稳定肠毒素STb是与猪源腹泻性分离株相关的最普遍毒素。本报告表明,当用大豆胰蛋白酶抑制剂阻断内源性蛋白酶活性时,STb在幼鼠和大鼠空肠肠袢中引发了剂量依赖性分泌反应。幼鼠对STb的敏感性远低于大鼠。大鼠空肠肠袢对STb的反应与STb剂量的对数呈线性关系,稀释倍数达10倍,共稀释10次。空肠前25%比肠道其余部分敏感性低。2.5小时的孵育期可产生最大反应。大鼠对STb的线性反应可用作生物测定。