Search

In our previous proteomics study, we identified Miro domain-containing protein (Miro-1), an excretory and secretory product of the pole worm, Haemonchus contortus , binds to goat peripheral blood mononuclear cells (PBMCs) in vivo . However, our understanding of the role of Miro-1and its potential immune impact on goat PBMCs is limited. The aim of the present study was to evaluate the effects of Miro-1 on functions of goat PBMCs in vitro. Recombinant protein (rMiro-1) was expressed in a prokaryote and incubated with goat PBMCs. Western blot analysis showed that rMiro-1 is successfully recognized by goat sera infected with H. contortus . Immunofluorescence analysis using rat antibodies against rMiro-1 indicated that this protein binds to goat PBMCs in vitro. Treatment of goat PBMCs/monocytes with various concentrations of rMiro-1 resulted in the upregulation of IL-2, IL-4, and IL-17, which in turn promoted cell proliferation, migration, the release of NO in PBMCs, and enhancement of phagocytosis of monocytes. These findings suggested that rMiro-1 stimulates PBMCs activity. [ABSTRACT FROM AUTHOR]

• rHCETFα suppressed the proliferation of goat PBMCs stimulated by concanavalin A. • rHCETFα significantly induced apoptosis in goat PBMCs. • rHCETFα modulated the secretion of cytokines in goat PBMCs. • rHCETFα up-regulated NO production in goat PBMCs. • rHCETFα inhibited phagocytosis of goat monocytes. 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. [ABSTRACT FROM AUTHOR]