Mejri Naceur, Hassen Imed Eddine, Knapp Jenny, Saidi Mouldi
Radiopharmaceutical Unit, National Centre of Sciences and Nuclear Technology, Sidi Thabet, Ariana, Tunisia.
Iran J Immunol. 2017 Mar;14(1):35-50.
Despite advances toward an improved understanding of the evasive mechanisms leading to the establishment of cystic echinococcosis, the discovery of specific immunosuppressive mechanisms and related factors are of great interest in the development of an immunotherapeutic approach.
To elucidate immunosuppressive effects of bioactive factors contained in chromatographic fractions from hydatid cystic fluid (HCF) of Echinococcus granulosus.
Hydatid cystic fluid was fractionated by reverse phase chromatography. Non-specific Concanavalin A-driven proliferation of spleen cells was used to determine specific inhibitory fractions. Trypan blue exclusion test and flowcytometry analysis were performed to check whether highly inhibitory fractions of HCF have apoptotic effect on peritoneal macrophages. Western blot analysis was used to determine proteolytic effects of parasitic antigens on major histocompatibility complex (MHC) class II (I-a) contained in membrane proteins extract from macrophages.
High concentrations of HCF and few of chromatographic fractions suppressed spleen cells proliferation. Fractions 7 and 35 were the highest inhibitory fractions. Specifically fraction 35 and to a lesser extent HCF induced apoptosis in peritoneal naive macrophages. However, HCF and the fraction 7 proteolytically altered the expression of MHC class II molecules on peritoneal macrophages. The proteolytic molecule was identified to be a serine protease. Macrophages taken at the chronic and end phase from cystic echinococcosis-infected mice were able to uptake and process C-Ovalbumine-FITC. These cells expressed a drastically reduced level of (I-a) molecules.
Our study present new aspects of immune suppression function of E. granulosus. Further molecular characterization of apoptotic and proteolytic factors might be useful to develop immunotherapeutic procedure to break down their inhibitory effects.
尽管在更好地理解导致囊性棘球蚴病形成的逃避机制方面取得了进展，但发现特定的免疫抑制机制和相关因素对于免疫治疗方法的开发具有重要意义。
阐明细粒棘球绦虫包虫囊液（HCF）色谱馏分中所含生物活性因子的免疫抑制作用。
采用反相色谱法对包虫囊液进行分离。用非特异性伴刀豆球蛋白A驱动的脾细胞增殖来确定特定的抑制馏分。进行台盼蓝排斥试验和流式细胞术分析，以检查HCF的高抑制馏分对腹腔巨噬细胞是否具有凋亡作用。采用蛋白质印迹分析来确定寄生虫抗原对巨噬细胞膜蛋白提取物中主要组织相容性复合体（MHC）II类（I-a）的蛋白水解作用。
高浓度的HCF和少数色谱馏分抑制脾细胞增殖。馏分7和35是抑制作用最强的馏分。具体而言，馏分35以及程度较轻的HCF可诱导腹腔幼稚巨噬细胞凋亡。然而，HCF和馏分7可蛋白水解改变腹腔巨噬细胞上MHC II类分子的表达。经鉴定，蛋白水解分子为丝氨酸蛋白酶。取自囊性棘球蚴病感染小鼠慢性期和末期的巨噬细胞能够摄取和处理C-卵清蛋白-FITC。这些细胞表达的（I-a）分子水平大幅降低。
我们的研究揭示了细粒棘球绦虫免疫抑制功能的新方面。对凋亡和蛋白水解因子进行进一步的分子表征可能有助于开发免疫治疗程序以消除其抑制作用。
