Suppression and modulation of the host immune response to parasitic nematodes have been extensively studied. In the present study, we cloned and produced recombinant electron transfer flavoprotein α subunit (ETFα) protein from Haemonchus contortus (rHCETFα), a parasitic nematode of small ruminants, and studied the effect of this protein on modulating the immune response of goat peripheral blood mononuclear cells (PBMCs) and monocytes. Immunohistochemical tests verified that the HCETFα protein was localized mainly in the intestinal wall and on the body surface of worms. Immunoblot analysis revealed that rHCETFα was recognized by the serum of goats artificially infected with H. contortus. Immunofluorescence analysis indicated that rHCETFα bound to the surface of PBMCs. rHCETFα was co-incubated with goat PBMCs to observe the immunomodulatory effects exerted by HCETFα on proliferation, apoptosis, cytokine secretion and nitric oxide (NO) production. The results showed that rHCETFα suppressed the proliferation of goat PBMCs stimulated by concanavalin A and induced apoptosis in goat PBMCs. After rHCETFα exposure, IL-2, IL-4, IL-17A and TNF-α expression was markedly reduced, whereas secretion of TGF-β1 was significantly elevated, in goat PBMCs. Moreover, rHCETFα up-regulated NO production in a dose-dependent manner. FITC-dextran internalization assays showed that rHCETFα inhibited phagocytosis of goat monocytes. These results elucidate the interaction between parasites and hosts at the molecular level, suggest a possible immunomodulatory target and contribute to the search for innovative proteins that may be candidate targets for drugs and vaccines.

已经广泛研究了宿主对寄生线虫的免疫应答的抑制和调节。在本研究中，我们从小反刍动物的寄生线虫Haemonchus contortus（rHCETFα）克隆并生产了重组电子转移黄素蛋白亚基（ETFα）蛋白，并研究了该蛋白对调节山羊外周血单核免疫反应的影响。细胞（PBMC）和单核细胞。免疫组织化学测试证实，HCETFα蛋白主要位于蠕虫的肠壁和体表。免疫印迹分析表明，rHCETFα是通过人工感染山羊血清公认的捻转血矛线虫。免疫荧光分析表明，rHCETFα与PBMC的表面结合。rHCETFα与山羊PBMC共同孵育，观察HCETFα对增殖，凋亡，细胞因子分泌和一氧化氮（NO）产生的免疫调节作用。结果表明，rHCETFα抑制了伴刀豆球蛋白A刺激的山羊PBMCs的增殖，并诱导了山羊PBMCs的凋亡。暴露于rHCETFα后，山羊PBMC中IL-2，IL-4，IL-17A和TNF-α的表达显着降低，而TGF-β1的分泌显着升高。此外，rHCETFα以剂量依赖性方式上调NO的产生。FITC-葡聚糖内在化分析表明，rHCETFα抑制了山羊单核细胞的吞噬作用。这些结果阐明了寄生虫与宿主之间在分子水平上的相互作用，