Twenty-five stains of E coil swine origin, were nsl to determine the cducuon of heat-stable enterotoxin (Si) and heat-labile enterotoxin (Li) by means of rabbit intestine ligated test. Twelve of the stains prcducaiSt 9 stains Lt and lOofthe stains contained neither of the enterotoxin. Only 6 of then rrcduced bo1h ldnds of entrotoxins.
The OK antigens were ererl from individual culture of the stains. A concen tation of 10-12% transmittance by the photcelectric colorimeter (containing about 4-5 xl CY’9 CFIJhn1 density) of the kecterin was employed to imsnunia the rabbit, two rabbit for each stain. Four &osters were rerformed at an interval of five days. Serum was collected one week afater the last incculation, and se:l at -2CftD lefcqe use. The reasults of plate agglutination tests indicated that the hyerimmune serum reacted secificaily and strongly with homologous stain, and some with heterologous stains with varying degree of intensity. The serum titers were varying from >QCI) to x25,&I) by means of tuke agglutination test.
It was noti thatthe antigenofstains 01253 (0147: K89 K88ac), El45 (0141:K85ac), ES? (0138: K81), Vi 89 (0108: K’Vl 89:), and V50 (010: K”V50”) reacted with much more heterologous immune sea than thc€e of other stains. n cause of tiltrculccisincatdein Taiwan, as a rule.