目的　从中毒性休克综合征爆发流行现场获取的病原菌 ,进行增菌培养 ,从病原菌分泌物中分离、纯化外毒素蛋白 ,以对其致病性进行实验研究。方法　将现场分离的缓症链球菌增菌培养后 ,所得上清液分别经 2 0 %、40 %、6 0 %、80 %硫酸铵盐析 ,进一步经快速蛋白液相色谱系统 (FPLC)最终纯化 ,分别皮下注射新西兰兔 ,观察有否发热。引起新西兰兔对大肠杆菌内毒素致死性休克的敏感性实验 :先给实验组新西兰兔皮下注射纯化的链球菌外毒素 10 μg ,4h后静脉注射 10 μg大肠杆菌内毒素 ,对照组仅注射 10 μg大肠杆菌内毒素。 结果　经FPLC最终纯化的 2 0 %硫酸铵盐析蛋白 (分子量 340 0 0 )有致热性 ,可使新西兰兔平均体温升高 1℃左右 ,病理见脾脏有丝分裂增加。纯化的链球菌外毒素可增加新西兰兔对大肠杆菌内毒素致死性休克的敏感性 :实验组动物出现休克的临床表现 ,分别于 16～ 2 9h内死亡 ;而仅注射 10 μg大肠杆菌内毒素的对照组动物无上述表现。 结论　缓症链球菌外毒素蛋白是一种新的链球菌致热性外毒素 OBJECTIVE To isolate and purify exotoxin protein from the pathogen secretions and to study the pathogenicity of the pathogenic bacteria from the epidemic scene of the outbreak of toxic shock syndrome. Methods Streptococcus pneumoniae isolated from the field was enriched and cultured. The resulting supernatants were respectively subjected to 20%, 40%, 60% and 80% ammonium sulfate salting-out and further purified by FPLC Purification, were injected subcutaneously New Zealand rabbits, observe whether fever. New Zealand rabbits caused by E. coli endotoxic lethal shock experiment: New Zealand rabbits were given subcutaneous injection of purified streptococcal exotoxin 10 μg, 4 h after intravenous injection of 10 μg E. coli endotoxin in the control group only injected with 10 μg E. coli endotoxin. Results The thermostability of 20% ammonium sulfate salting-out protein (molecular weight 340 0 0) finally purified by FPLC increased the average body temperature of New Zealand rabbits by about 1 ℃ and increased the mitosis in the pathology. Purified Streptococcus exotoxin can increase the sensitivity of New Zealand rabbits to E. coli endotoxic shock: the clinical manifestations of shock in the experimental group animals, respectively, within 16 ~ 29h death; and only injection of 10 ug E. coli endotoxin Control animals did not show the above performance. Conclusion Streptococcus mutans exotoxin protein is a novel Streptococcus thermophilic exotoxin