【作者】 郑翰；

【导师】 徐建国；

【作者基本信息】 中国疾病预防控制中心 ， 病原生物学， 2008， 博士

【摘要】 2005年四川暴发人感染猪链球菌疫情,引起罕见的链球菌中毒性休克样症状,病死率高达62.3%。我们的研究证明其病原菌是猪链球菌序列7型(ST7)。ST7型猪链球菌是ST1型猪链球菌的变异,毒力比ST1型菌株有明显的增加。由于两型菌株都含有常见的毒力因子,因而需要引入新的观点来揭示这种毒力增强的机制,以便更好的了解猪链球菌的致病机理。本研究中两株分离自2005年四川猪链休克患者的ST7型菌株、一株分离自同一年分四川周边地区猪链患者的ST1型菌株以及一株被国外学者广泛研究的来源于病猪的ST1型菌株被用来进行比对研究。本研究证实两种ST型别刺激试验小鼠产生细胞因子的机制不同。ST7型菌株拥有比ST1型菌株更强的刺激PBMC,CD3~+T淋巴细胞,幼稚(CD45RA~+)T淋巴细胞的能力。而且这两型菌株刺激淋巴细胞增殖时均需抗原提呈细胞(APC)的辅助。但同种异体抗原提呈细胞就可以提供足够的协助能力。说明这种协助是MHC非限制性的。上述结果证实两型同属高致病性的猪链球菌中均包含有丝裂原成分,但ST7型菌株比ST1型菌株拥有更强的丝裂原活性。我们提出正是这种增强的丝裂原活性造成ST7型菌株比ST1型菌株拥有更强的致病能力。更多还原

【Abstract】 A large outbreak due to S.suis serotype 2 emerged in the summer of 2005 in Sichuan Province,China.In this outbreak,mortality and morbidity due tO STSLS were surprisingly high(62.3%).Much evidence indicated that the virulence of serotype 2 ST7 strains emerged in the summer of 2005 in China increased.The reason needs to be investigated in order to better understanding the pathogenic mechanism of Streptococcus suis sequence type 7 that was isolated from shock patients during the outbreak and high pathogenic ST1 strains were used to compare mutually.The present studies demonstrate that mechanism of inducing cytokines production was different between two type strains. ST7 strain possessed stronger capacity to stimulate T-cell,naive T-cell and PBMC proliferate than ST1 strain did.The T-cell response to two strains was dependent upon the presence of APCs.Histoincompatible APCs were sufficient to provide accessory signals to naive T- cell stimulated by two strains,indicating that both strains possess mitogens. But the mitogenic effect was different between them.We proposed that the difference in mitogenic effect between ST1 stains and ST7 strains contributed to the difference in virulence between them.The mitogenic effect should be emphasized when explained the mechanism of Streptococcus suis.更多还原