Zhao Jianqing, Pan Shan, Lin Lan, Fu Lei, Yang Chao, Xu Zhongmin, Wei YanMin, Jin Meilin, Zhang Anding
Unit of Animal Infectious Diseases, National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, Hubei 430070, P.R. China College of Veterinary Medicine, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, Hubei, 430070, P.R. China.
College of Veterinary Medicine, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, Hubei, 430070, P.R. China.
FEMS Microbiol Lett. 2015 Mar;362(6). doi: 10.1093/femsle/fnv022. Epub 2015 Feb 11.
Streptococcus suis (S. suis) ranks among the five most important porcine pathogens worldwide and occasionally threatens human health, especially in people that come into close contact with pigs or pork products. Streptococcus suis serotype 2 (SS2) is considered to be the most pathogenic and prevalent capsular type. As a first line of immune defense against SS2 infection, neutrophils can eliminate the invader not only by phagocytosis but also by neutrophil extracellular traps (NETs)-mediated killing. SS2 can resist phagocytosis through polysaccharide capsule (CPS), but how this strain evades the effects of NETs remains to be determined. The present study demonstrated that the epidemic strain 05ZY, the highly pathogenic strain P1/7 and the intermediately pathogenic strain A7 could induce the formation of NETs. Furthermore, SS2 strains could successfully resist NETs-mediated killing, and the CPS structure contributed to this resistance by escaping the trapping. Therefore, the CPS structure not only contributed to the SS2 strains' resistance to phagocytosis-mediated killing but also played an essential role in evading NETs trapping and further killing in vitro. This study strengthens our understanding of how S. suis can evade innate immune surveillance and elimination.
猪链球菌（S. suis）是全球五种最重要的猪病原体之一，偶尔会威胁人类健康，尤其是那些与猪或猪肉产品密切接触的人。猪链球菌2型（SS2）被认为是最具致病性和最普遍的荚膜型。作为抵御SS2感染的第一道免疫防线，中性粒细胞不仅可以通过吞噬作用消除入侵者，还可以通过中性粒细胞胞外陷阱（NETs）介导的杀伤作用来消除。SS2可以通过多糖荚膜（CPS）抵抗吞噬作用，但该菌株如何逃避NETs的作用仍有待确定。本研究表明，流行菌株05ZY、高致病性菌株P1/7和中度致病性菌株A7均可诱导NETs的形成。此外，SS2菌株能够成功抵抗NETs介导的杀伤作用，且CPS结构通过逃避捕获而促成了这种抗性。因此，CPS结构不仅有助于SS2菌株抵抗吞噬作用介导的杀伤，而且在体外逃避NETs捕获和进一步杀伤中也起着至关重要的作用。这项研究加深了我们对猪链球菌如何逃避天然免疫监视和清除的理解。
