The aim of this study was to characterize the biological properties of a novel aspartic protease-1 from Trichinella spiralis (TsASP1) and evaluate its potential in inducing immune response. TsASP1 gene was cloned and expressed in Escherichia coli BL21 (DE3). On Western blotting analysis with anti-rTsASP1 serum, native TsASP1 was detected in various T. spiralis phases other than newborn larvae (NBL). qPCR results showed that TsASP1 transcription was the highest in intestinal infective larvae (IIL) and the lowest in the NBL stage. Immunofluorescence test result shows that native TsASP1 was principally localized in stichosome, muscle cells of muscle larvae (ML) and IIL, and surrounded intrauterine embryos in female adult worms (AW). After silencing TsASP1 gene of the ML by siRNA, the worm development was significantly inhibited, showed by shorter AW and more wrinkles and longitudinal crack on epicuticle of AW on scanning electron microscopy; the AW and ML burdens were reduced by 41.82 and 56.36% respectively, compared with the control siRNA or PBS group (P < 0.001). Immunization of mice with rTsASP1 elicited an evident antibody response (serum IgG, IgG1/IgG2a and enteral sIgA), and systemic (spleen) and intestinal local mucosal (mesenteric lymph node) cellular immune response, demonstrated by a prominent elevation of IFN-γ and IL-4. The results suggested TsASP1 participated in T. spiralis development and survival in host, and immunization of mice with rTsASP1 induced systemic/intestinal local mucosal humoral and cellular immune response against Trichinella.

这项研究的目的是表征旋毛虫（TsASP1）的新型天冬氨酸蛋白酶1的生物学特性，并评估其诱导免疫反应的潜力。TsASP1基因被克隆并在大肠杆菌BL21（DE3）中表达。在与抗血清rTsASP1 Western印迹分析，在不同的检测本地TsASP1旋毛虫新生幼虫（NBL）以外的阶段。qPCR结果显示，TsASP1转录在肠道感染幼虫（IIL）中最高，而在NBL期最低。免疫荧光测试结果表明，天然TsASP1主要定位于雌性成虫（AW）的脉管，肌肉幼虫（ML）的肌肉细胞和IIL中，并围绕着子宫内的胚胎。用siRNA沉默ML的TsASP1基因后，蠕虫的发育受到了明显的抑制，扫描电镜观察到AW较短，AW表皮上有更多的皱纹和纵向裂缝，从而表明了蠕虫的发育。与对照组siRNA或PBS组相比，AW和ML负担分别减少了41.82和56.36％（P <0.001）。用rTsASP1免疫小鼠会引起明显的抗体反应（血清IgG，IgG1 / IgG2a和肠内sIgA），以及全身性（脾脏）和肠道局部粘膜（肠系膜淋巴结）细胞免疫反应，这通过IFN-γ和IL-4。结果表明TsASP1参加了旋毛虫的发展和生存的主机，并与rTsASP1小鼠的免疫诱导抗系统性/肠道局部黏膜体液免疫和细胞免疫反应旋毛虫。