Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis/College of Veterinary Medicine/College of Basic Medical Science, Jilin University, Changchun, China.
Mucosal Immunology Laboratory, Pediatric Gastroenterology Unit, Massachusetts General Hospital East, Boston, USA.
Parasit Vectors. 2017 Nov 21;10(1):579. doi: 10.1186/s13071-017-2522-9.
The nematode Trichinella pseudospiralis is an intracellular parasite of mammalian skeletal muscle cells and exists in a non-encapsulated form. Previous studies demonstrated that T. pseudospiralis could induce a lower host inflammatory response. Excretory-secretory (ES) proteins as the most important products of host-parasite interaction may play the main functional role in alleviating host inflammation. However, the ES products of T. pseudospiralis early stage are still unknown. The identification of the ES products of the early stage facilitates the understanding of the molecular mechanisms of the immunomodulation and may help finding early diagnostic markers.
In this study, we used two-dimensional gel electrophoresis (2-DE)-based western blotting coupled with matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/TOF-MS/MS) to separate and identify the T. pseudospiralis adult worms ES products immunoreaction-positive proteins. In total, 400 protein spots were separated by 2-DE. Twenty-eight protein spots were successfully identified using the sera from infected pigs and were characterized to correlate with 12 different proteins of T. pseudospiralis, including adult-specific DNase II-10, poly-cysteine and histidine-tailed protein isoform 2, serine protease, serine/threonine-protein kinase ULK3, enolase, putative venom allergen 5, chymotrypsin-like elastase family member 1, uncharacterized protein, peptidase inhibitor 16, death-associated protein 1, deoxyribonuclease II superfamily and golgin-45. Bioinformatic analyses showed that the identified proteins have a wide diversity of molecular functions, especially deoxyribonuclease II (DNase II) activity and serine-type endopeptidase activity.
Early candidate antigens from the ES proteins of T. pseudospiralis have been screened and identified. Our results suggest these proteins may play key roles during the T. pseudospiralis infection and suppress the host immune response. Further, they are the most likely antigen for early diagnosis and the development of a vaccine against the parasite.
旋毛虫假类圆线虫是一种哺乳动物骨骼肌细胞内寄生虫，以非囊包形式存在。先前的研究表明，旋毛虫假类圆线虫能够诱导较低的宿主炎症反应。排泄分泌（ES）蛋白作为宿主-寄生虫相互作用的最重要产物，可能在缓解宿主炎症中发挥主要功能作用。然而，旋毛虫假类圆线虫早期的 ES 产物仍然未知。鉴定早期的 ES 产物有助于理解免疫调节的分子机制，并可能有助于寻找早期诊断标志物。
在这项研究中，我们使用基于二维凝胶电泳（2-DE）-western 印迹结合基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF/TOF-MS/MS）分离和鉴定旋毛虫成虫 ES 产物免疫反应阳性蛋白。通过 2-DE 共分离出 400 个蛋白斑点。使用感染猪的血清成功鉴定了 28 个蛋白斑点，并与旋毛虫假类圆线虫的 12 种不同蛋白相关联，包括成虫特异性 DNA 酶 II-10、多半胱氨酸和组氨酸尾蛋白同工型 2、丝氨酸蛋白酶、丝氨酸/苏氨酸蛋白激酶 ULK3、烯醇酶、假定毒液过敏原 5、糜蛋白酶样弹性蛋白酶家族成员 1、未鉴定蛋白、肽酶抑制剂 16、死亡相关蛋白 1、脱氧核糖核酸酶 II 超家族和高尔基体蛋白 45。生物信息学分析表明，鉴定出的蛋白具有广泛的分子功能多样性，特别是 DNA 酶 II（DNase II）活性和丝氨酸内肽酶活性。
从旋毛虫假类圆线虫 ES 蛋白中筛选和鉴定了早期候选抗原。我们的结果表明，这些蛋白可能在旋毛虫假类圆线虫感染过程中发挥关键作用，并抑制宿主免疫反应。此外，它们是寄生虫早期诊断和疫苗开发的最有可能的抗原。
