Abstract：
Streptococcus equissp.zooepidemicus (SEZ) is a crucial pathogen and contributes to various infections in numerous animal species. Swine streptococcicosis outbreak caused by SEZ has been reported in several countries in recent years. SzM protein is a cell membrane-anchored protein, which exhibits as an important virulence factor of SEZ. Effects of SzM protein on host innate immune need further study. Here, recombinant SzM (rSzM) protein of the SEZ was obtained, and mice were intraperitoneally injected with rSzM protein. We discovered that rSzM protein can recruit neutrophils into the injected site. In further study, neutrophils were isolated and treated with rSzM protein, NETs release were triggered by rSzM protein independently, and GSDMD protein was promoted-expressed and activated. In order to investigate the role of GSDMD in NETs formation, neutrophils isolated from WT mice and GSDMD-/- mice were treated with rSzM protein. The results showed that GSDMD deficiency suppressed the NETs release. In conclusion, SzM protein of SEZ can trigger the NETs release in a GSDMD-depending manner.
摘要：
马链球菌。动物流行病（SEZ）是一种重要的病原体，并有助于许多动物物种的各种感染。近年来，一些国家已经报道了由经济特区引起的猪链球菌病暴发。SzM蛋白是一种细胞膜锚定蛋白,它是经济特区的重要毒力因子。SzM蛋白对宿主固有免疫的影响有待进一步研究。这里,获得SEZ的重组SzM（rSzM）蛋白，小鼠腹腔注射rSzM蛋白。我们发现rSzM蛋白可以招募嗜中性粒细胞进入注射部位。在进一步的研究中,分离中性粒细胞并用rSzM蛋白处理，NETs释放由rSzM蛋白独立触发，GSDMD蛋白被促进表达和激活。为了研究GSDMD在NETs形成中的作用，用rSzM蛋白处理从WT小鼠和GSDMD-/-小鼠分离的嗜中性粒细胞。结果表明，GSDMD缺乏抑制了NETs的释放。总之,SEZ的SzM蛋白可以以GSDMD依赖的方式触发NETs释放。
