Hulting Greta, Flock Margareta, Frykberg Lars, Lannergård Jonas, Flock Jan-Ingmar, Guss Bengt
Department of Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
FEMS Microbiol Lett. 2009 Sep;298(1):44-50. doi: 10.1111/j.1574-6968.2009.01698.x.
Streptococcus equi ssp. equi causes strangles, a highly contagious and serious disease in the upper respiratory tract of horses. Streptococcus equi ssp. zooepidemicus, another subspecies of this genus, is regarded as an opportunistic commensal in horses. The present study describes the characterization of two novel immunoglobulin G (IgG) endopeptidases of these subspecies, IdeE2 and IdeZ2. Both enzymes display sequence similarities with two previously characterized IgG endopeptidases, IdeE of S. equi ssp. equi and IdeZ of S. equi ssp. zooepidemicus. IdeE2 and IdeZ2 display high substrate-specificity in comparison with IdeE and IdeZ, as they both completely cleave horse IgG, while the activity against IgG from mouse, rabbit, cat, cow, sheep and goat is low or absent. The potential use of IdeE and IdeE2 as vaccine components was studied in a mouse infection model. In this vaccination and challenge study, both enzymes induced protection against S. equi ssp. equi infection.
马链球菌马亚种可引发马腺疫，这是一种在马的上呼吸道中具有高度传染性的严重疾病。该属的另一个亚种——马链球菌兽疫亚种，被认为是马体内的一种机会性共生菌。本研究描述了这两个亚种的两种新型免疫球蛋白G（IgG）内肽酶IdeE2和IdeZ2的特性。这两种酶与之前已鉴定的两种IgG内肽酶——马链球菌马亚种的IdeE和马链球菌兽疫亚种的IdeZ具有序列相似性。与IdeE和IdeZ相比，IdeE2和IdeZ2表现出较高的底物特异性，因为它们都能完全切割马IgG，而对来自小鼠、兔子、猫、牛、绵羊和山羊的IgG的活性较低或没有活性。在小鼠感染模型中研究了IdeE和IdeE2作为疫苗成分的潜在用途。在这项疫苗接种和攻毒研究中，这两种酶均诱导了针对马链球菌马亚种感染的保护作用。
