Recombinant protein of Haemonchus contortus small GTPase ADP-ribosylation factor 1 (HcARF1) modulate the cell mediated immune response in vitro

Hepatocellular carcinoma-associated antigen 59 and ADP-ribosylation factor 1 with poly (lactic-co-glycolic acid): A promising candidate as nanovaccine against haemonchosis

Haemonchus contortus (H. contortus) ADP-ribosylation factor 1 (Hc-ARF1) and Hepatocellular carcinoma-associated antigen 59 (Hc-HCA59) are recognized to largely regulate the immune responses of host cells. However, studies about the protective efficacy of the two molecules are poorly unknown. In this research, combinations of recombinant Hc-HCA59 (rHc-HCA59) and Hc-ARF1 (rHc-ARF1) proteins were amalgamated with poly (lactic-co-glycolic acid) (PLGA) nanoparticles adjuvant in order to investigate their protection potential against H. contortus in goats. The results demonstrated that the levels of IgG, IgA, IgE, and IL-4 were noticeably enhanced in the rHc-HCA59 and rHc-ARF1 (rHc-HCA59+rHc-ARF1) group before H. contortus third-stage larvae (L3) challenge. After the L3 challenge, the levels of IL-17, IL-9, and TGF-β were considerably upregulated in the rHc-HCA59+rHc-ARF1 group. In the meantime, the abomasal worm burdens and the fecal eggs were reduced by 63.2% and 69.4% respectively in the rHc-HCA59+rHc-ARF1 group. According to the studies, PLGA nanoparticles immobilized with rHc-HCA59 and rHc-ARF1 proteins conferred partial protection and were expected to be a potential candidate for developing nano vaccines to combat goat haemonchosis.

Regulatory effects of a novel cysteine protease inhibitor in Baylisascaris schroederi migratory larvae on mice immune cells

Background

The giant panda (Ailuropoda melanoleuca) is a well-known, rare and endangered species. Baylisascaris schroederi is a pathogenic ascarid. Infection with B. schroederi may cause death in giant pandas. At present, the immune evasion mechanism of B. schroederi is little known. Cysteine protease inhibitors (CPI) play important roles in the regulation of host immune responses against certain nematodes. In this study, we focused on the analysis of the regulation of B. schroederi migratory larvae CPI (rBsCPI-1) on mice immune cells.

Methods

First, the pattern recognition receptors on the surface of peripheral blood mononuclear cells (PBMCs) and the signal pathways that transduce extracellular signals into the nucleus activated by rBsCPI-1 were identified. Then, the regulatory effects of rBsCPI-1 on PBMCs physiological activities were detected. Finally, the effects of rBsCPI-1 on TLR signaling pathway activation and NF-κB phosphorylation in mice immunized with recombinant protein were analysed.

Results

The results suggested that rBsCPI-1 secreted by B. schroederi migratory larvae is mainly recognized by TLR2 and TLR4 on PBMCs. Extracellular signals are transduced into the nucleus through the MAPK and NF-κB signaling pathways, enhancing the phagocytosis, migration, and apoptosis of PBMCs; meanwhile, rBsCPI-1 induces high expression of NO. Thus, rBsCPI-1 plays a role in immune regulation. In addition, the high expression of negative regulatory factors also ensured that TLR activation is maintained at the optimal level.

Conclusions

rBsCPI-1 can transduce regulatory signals into immune cells by activating the TLR2/4-NF-κB/MAPK signaling pathway, having a certain regulatory effect on the physiological activities. Meanwhile, rBsCPI-1 can maintain the immune response in a balance by limiting the over-activation of the TLRs signaling pathway and thus contributes to B. schroederi immune evasion.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05240-8.

The immunogenic maturation of goat monocyte-derived dendritic cells and upregulation of toll-like receptors by five antigens of Haemonchus contortus in-vitro

Previously, it was found that several proteins of Haemonchus contortus were involved in the stimulation of the host immune system. However, the information about the selection of superlative antigens with immunogenic efficacies on host DCs is lacking. In the current study, the stimulatory effects of five recombinant proteins (elongation factor-1α, arginine kinase, ES-15, ES-24, and ADP-ribosylation factor 1) of H. contortus on the maturation of goat monocyte-derived dendritic cells (md-DCs) were reported. Recombinant proteins were purified separately in E. coli expression and incubated with isolated goat peripheral blood mononuclear cells (PBMC). Immunofluorescence assay (IFA) results confirmed the binding of these molecules to the md-DC's surface as compared to control groups. In the flow cytometry analysis, recombinant proteins induced md-DC stimulation via the up-regulation of the expression of the costimulatory molecule (CD80) and MHC-II. Quantitative RT-PCR data showed a significant increase in the expression of specific genes of the WNT and toll-like receptor (TLR) signaling pathways. The result of ELISA indicated the higher levels of cytokine (IL-10, IL-12, IFN-γ, and TNF-α) secretion in the md-DC compared to the negative (pET-32a His-Tag) and blank (PBS) control groups. The data gives valuable support in the selection of potential antigens for future studies on the immunomodulation of the host against the infection of H. contortus.

Nanoparticles (PLGA and Chitosan)-Entrapped ADP-Ribosylation Factor 1 of Haemonchus contortus Enhances the Immune Responses in ICR Mice

ADP-ribosylation factor 1 (HcARF1) is one of the Haemonchus contortus (H. contortus) excretory/secretory proteins involved in modulating the immune response of goat peripheral blood mononuclear cells (PBMC). Here, we evaluated the immunogenic potential of recombinant HcARF1 (rHcARF1) against H. contortus infection in Institute of Cancer Research (ICR) mice. Briefly, rHcARF1 was entrapped in poly (D, L-lactide-co-glycolide) (PLGA) and chitosan (CS) nanoparticles (NP) and injected into mice as a vaccine. Fifty-six ICR mice were assigned randomly into seven groups, with eight animals in each group, and they were vaccinated subcutaneously. At the end of the experiment (14th day), the blood and the spleen were collected from euthanized mice to detect lymphocyte proliferation, cytokine analysis, and the production of antigen-specific antibodies. Scanning electron microscope was used to determine the size, morphology, and zeta potential of nanoparticles. Flow cytometry was performed, which presented the increase percentages of CD4⁺ T cells (CD3e⁺CD4⁺), CD8⁺ T cells (CD3e⁺CD8⁺) and dendritic cells (CD11c⁺CD83⁺, CD11c⁺CD86⁺) in mice vaccinated with rHcARF1+PLGA NP. Immunoassay analysis show raised humoral (Immunoglobulin (Ig)G1, IgG2a, IgM) and cell-mediated immune response (Interleukin (IL)-4, IL-12, and IL-17, and Interferon (IFN)-γ) induced by rHcARF1+PLGA NP. Experimental groups that were treated with the antigen-loaded NP yield higher lymphocyte proliferation than the control groups. Based on these results, we could propose that the rHcARF1 encapsulated in NP could stimulate a strong immune response in mice rather than administering alone against the infection of H. contortus.

Advances in the Development of Anti-Haemonchus contortus Vaccines: Challenges, Opportunities, and Perspectives

The gastrointestinal nematode parasite Haemonchus contortus (H. contortus) is a resident of tropical and subtropical regions worldwide that imposes significant production losses, economic losses, and animal health issues in the small ruminant industry, particularly sheep and goats. Considerable efforts have been made to understand how immunity is elicited against H. contortus infection. Various potential vaccine antigens have been tested by different methods and strategies applied in animal models, and significant progress has been made in the development of vaccines against H. contortus. This review highlighted and shared the knowledge about the current understanding of host immune responses to H. contortus and ongoing challenges in the development of a protective, effective, and long-lasting vaccine against H. contortus infection. We have also pinpointed some achievements and failures in the development and testing of vaccines, which will establish a road map for future research directions to explore new effective vaccine candidates for controlling and preventing H. contortus infection.

Haemonchus contortus: siRNA mediated knockdown of matrix metalloproteinase 12A (MMP-12) results in reduction of infectivity

BACKGROUND

RNA interference (RNAi) is an important tool to determine the role of genes. RNAi has been widely used to downregulate target molecules, resulting in the reduction of mRNA for protein expression. Matrix metalloprotease 12A (MMP-12) is known to have important roles during embryonic development, organ morphogenesis and pathological processes in animals. However, MMP-12 from Haemonchus contortus has not been characterized.

METHODS

Haemonchus contortus MMP-12 gene was cloned and recombinant protein of MMP-12 (rHc-MMP-12) was expressed. Binding activities of rHc-MMP-12 to goat peripheral blood mononuclear cells (PBMCs) were assessed by immunofluorescence assay (IFA) and the immuno-regulatory effects of rHc-MMP-12 on cell proliferation and nitric oxide production were observed by co-incubation of rHc-MMP-12 with goat PBMCs. Furthermore, a soaking method was used to knockdown the expression of Hc-MMP12 gene using three siRNA, targeting different regions of the gene and infectivity of effective siRNA on the development of H. contortus was evaluated in goat.

RESULTS

rHc-MMP-12 was successfully expressed in an expression vector as well as the tissues of the cuticle of adult H. contortus worms and a successful binding with PBMCs surface were observed. Increased cellular proliferation and nitric oxide production by goat PBMCs was observed in a dose-dependent manner. Quantitative real time PCR (qRT-PCR) results confirmed the successful silencing of Hc-MMP-12 gene in siRNA of 1, 2 and 3 treated third-stage larvae (L3) of H. contortus in vitro. The most efficient qRT-PCR-identified siRNA template was siRNA-2, with a 69% suppression rate compared to the control groups. Moreover, in an in vivo study, silencing of the Hc-MMP-12 gene by siRNA-2 reduced the number of eggs (54.02%), hatchability (16.84%) and worm burden (51.47%) as compared to snRNA-treated control group. In addition, a shorter length of worms in siRNA-2-treated group was observed as compared to control groups.

CONCLUSIONS

Our results indicate that siRNA-mediated silencing of Hc-MMP-12 gene in H. contortus significantly reduce the egg counts, larval hatchability, and adult worm counts and sizes. The findings of the present study demonstrate important roles of Hc-MMP-12 in the development of H. contortus.

Tropomyosin: An Excretory/Secretory Protein from Haemonchus contortus Mediates the Immuno-Suppressive Potential of Goat Peripheral Blood Mononuclear Cells In Vitro

During host-parasite interactions, binding of excretory/secretory proteins (ESPs) on the host immune cells is considered the fundamental phase for regulation of immune responses. In this study, gene encoding Haemonchus contortus tropomyosin (Hc-TpMy), was successfully cloned and expressed, and the recombinant protein after host cell surface attachment was evaluated for immune functional analysis with goat peripheral blood mononuclear cells (PBMCs) in vitro. The isopropyl-β-D-thiogalactopyranoside (IPTG)-induced recombinant protein was successfully recognized by the sera of rat experimentally infected with rHc-TpMy. The immunofluorescence assay detected attachment of rHc-TpMy on the surface of host PBMCs. Furthermore, immunoregulatory roles of rHc-TpMy on cytokines expression, PBMC proliferation, migration, nitric oxide (NO) production, apoptosis and monocytes phagocytosis were observed. The results showed that expression of IL-4 and IFN-γ cytokines, cell proliferation, NO production and PBMC migration were significantly suppressed by goat PBMCs after co-incubation with rHc-TpMy protein. However, the productions of IL-10, IL-17 and TGF-β1 cytokines, PBMCs apoptosis and monocytes phagocytosis were elevated at dose dependent manner. Our findings indicated that rHc-TpMy is an important ES binding protein exhibit distinct immuno-suppressive roles on goat PBMCs which might be a potential molecular target to control haemonchosis in future.

Recombinant elongation factor 1 alpha of Haemonchus contortus affects the functions of goat PBMCs

Excretory/secretory proteins of Haemonchus contortus (HcESPs) intermingle comprehensively with host immune cells and modulate host immune responses. In this study, H contortus ES antigen named as elongation factor 1 alpha (HcEF‐1α) was cloned and expressed. The influences of recombinant HcEF‐1α on multiple functions of goat peripheral blood mononuclear cells (PBMCs) were observed in vitro. Immunoblot analysis revealed that rHcEF‐1α was recognized by the serum of goat infected with H contortus. Immunofluorescence analysis indicated that rHcEF‐1α was bound on surface of PBMCs. Moreover, the productions of IL‐4, TGF‐β1, IFN‐γ and IL‐17 of cells were significantly modulated by the incubation with rHcEF‐1α. The production of interleukin IL‐10 was decreased. Cell migration, cell proliferation and cell apoptosis were significantly increased; however, nitric oxide production (NO) was significantly decreased. The MHC II molecule expression of cells incubated with rHcEF‐1α was increased significantly, whereas MHC‐I was not changed as compared to the control groups (PBS control and pET32a). These findings indicated that rHcEF‐1α protein might play essential roles in functional regulations of HcESPs on goat PBMC and mediate the immune responses of the host during host‐parasite relationship.

Characterization of Haemonchus contortus Excretory/Secretory Antigen (ES-15) and Its Modulatory Functions on Goat Immune Cells In Vitro

Small size excretory/secretory (ES) antigens of the Haemonchus contortus parasite have intense interest among researchers for understanding the molecular basis of helminths immune regulation in term of control strategies. Immunomodulatory roles of H. contortus ES-15 kDa (HcES-15) on host immune cells during host–parasite interactions are unknown. In this study, the HcES-15 gene was cloned and expression of recombinant protein (rHcES-15) was induced by isopropyl-ß-d-thiogalactopyranoside (IPTG). Binding activity of rHcES-15 to goat peripheral blood mononuclear cells (PBMCs) was confirmed by immunofluorescence assay (IFA) and immunohistochemical analysis showed that H. contortus 15 kDa protein localized in the outer and inner structure of the adult worm, clearly indicated as the parasite’s ES antigen. The immunoregulatory role on cytokines production, cell proliferation, cell migration, nitric oxide (NO) production, apoptosis, and phagocytosis were observed by co-incubation of rHcES-15 with goat PBMCs. The results showed that cytokines IL-4, IL-10, IL-17, the production of nitric oxide (NO), PBMCs apoptosis, and monocytes phagocytosis were all elevated after cells incubated with rHcES-15 at differential protein concentrations. We also found that IFN-γ, TGF-β1, cells proliferation and migration were significantly suppressed with the interaction of rHcES-15 protein. Our findings indicated that low molecular ES antigens of H. contortus possessed discrete immunoregulatory roles, which will help to understand the mechanisms involved in immune evasion by the parasite during host–parasite interactions.

Galectin Domain Containing Protein from Haemonchus contortus Modulates the Immune Functions of Goat PBMCs and Regulates CD4+ T-Helper Cells In Vitro

Galectins are glycan-binding proteins that are widely expressed and distributed in mammalian tissues as well as cells of innate and adaptive immune responses. CD4+ T-helper cells differentiate into effector subsets in response to cytokines. T helper 9 cells are one of the recently described subsets of effector T cells that are relatively new and less studied. In this study, galectin domain containing protein from Haemonchus contortus (Hc-GDC) was cloned, expressed in pET32a, and immunoblotting was performed. Localization of recombinant (r)Hc-GDC on outer and inner surface of H. contortus worm and binding with goat Peripheral Blood Mononuclear cells (PBMCs) were performed using immunofluorescence assay. Moreover, effects of rHc-GDC on proliferation, apoptosis, cell migration, and the nitric oxide production in goat PBMCs were evaluated. Furthermore, modulatory effects of rHc-GDC on production of Th1, Th2, and Th9 cells were evaluated by flowcytometry and on interferon gamma, interleukin (IL)-4 and IL-9 were evaluated by quantitative real-time polymerase chain reaction. The results demonstrated that rHc-GDC was successfully cloned, expressed in expression vector as well as in the gut surface of adult H. contortus worm and successful binding with PBMCs surface were observed. Immunoblotting results revealed that rHc-GDC is an important active protein of H. contortus excretory and secretory products. Moreover, the interaction of rHc-GDC with host cells increased the production of Th2, Th9 cells, IL4, IL-9, PBMC proliferation, nitric oxide, and cell migration. No effects of rHc-GDC were observed on PMBC apoptosis, production of Th1 cells, and secretions of IFN- and IL-10 cytokines. These findings indicate that recombinant GDC protein from H. contortus modulates the immune functions of goat PBMCs and has the potential to enhance protective immunity by inducing T helper-9-derived IL-9 in vitro.

Succinate Coenzyme A Ligase Beta-Like Protein from Trichinella spiralis Suppresses the Immune Functions of Rat PBMCs in Vitro and Inhibits the Secretions of Interleukin-17 in Vivo

Succinate Coenzyme A ligase beta-like protein (SUCLA-β) is a subunit of Succinyl-coenzyme A synthetase, which is involved in substrate synergism, unusual kinetic reaction in which the presence of SUCLA-β for one partial reaction stimulates another partial reaction. Trichinella spiralis is a parasitic nematode, which may hinder the development of autoimmune diseases. Immunomodulatory effects of SUCLA-β from Trichinella spiralis in the parasite-host interaction are unidentified. In this study the gene encoding T. spiralis SUCLA-β was cloned and expressed. Binding activities of recombinant T. spiralis SUCLA-β (rTs-SUCLA-β) to rat peripheral blood mononuclear cells (PBMCs) were checked by immunofluorescence assay (IFA) and the immuno-regulatory effects of rTs-SUCLA-β on cell migration, cell proliferation, nitric oxide (NO) production and apoptosis were observed by co-incubation of rTs-SUCLA-β with rat PBMCs in vitro, while cytokine secretions in rTs-SUCLA-β treated rats were evaluated in vivo. Furthermore, phagocytosis of monocytes was detected by flow cytometry and effects of rTs-SUCLA-β-induced protective immunity on T. spiralis adult worms and muscle larva were evaluated in rats. The IFA results revealed that rTs-SUCLA-β could bind to rat PBMCs. Treatment of PBMCs with rTs-SUCLA-β significantly decreased the monocyte phagocytosis, cell migration and cell proliferation, while NO production and apoptosis of PBMCs were unaffected. Results of the in vivo study showed that the IL-17 secretion decreased significantly after rTs-SUCLA-β administration in rats, while no significant effects were observed on the secretions of IFN-γ, IL-9, TGF-β and IL-4. Moreover, significant reduction of T. spiralis muscle larvae burden and significant increase in anti-rTs-SUCLA-β immunoglobulin level of IgG, IgG1 and IgG2a was observed in rTs-SUCLA-β-administered rats. The results indicated that rTs-SUCLA-β may be a potential target for controlling T. spiralis infection by suppressing the immune functions of the rat PBMCs and by reducing the parasite burden. Additionally it may also contribute to the treatment of autoimmune diseases and graft rejection by suppressing IL-17 immune response in the host.

Hepatocellular carcinoma-associated antigen 59 of Haemonchus contortus modulates the functions of PBMCs and the differentiation and maturation of monocyte-derived dendritic cells of goats in vitro

BACKGROUND

Hepatocellular carcinoma-associated antigen 59 (HCA59), which is one of the most important excretory/secretory products of Haemonchus contortus (HcESPs), is known to have antigenic functions. However, its immunomodulatory effects on host cells are poorly understood.

METHODS

Here, we cloned the HCA59 gene and expressed the recombinant protein of HCA59 (rHCA59). Binding activities of rHCA59 to goat peripheral blood mononuclear cells (PBMCs) and dendritic cells (DCs) were checked by immunofluorescence assay (IFA) and the immunoregulatory effects of rHCA59 on cytokine secretions, cell migration, cell proliferation, nitric oxide production, and changes in expression of genes in related pathways were observed by co-incubation of rHCA59 with goat PBMCs and DCs. Monocyte phagocytosis and characterization of goat blood DC subsets were detected by flow cytometry.

RESULTS

The IFA results revealed that rHCA59 could bind to PBMCs and DCs. Treatment of PBMCs with rHCA59 significantly increased cellular proliferation and NO production in a dose-dependent manner, while cell migration was vigorously blocked. Treatment with rHCA59 significantly suppressed monocytes phagocytosis. The quantity of surface marker CD80 on DCs increased significantly after rHCA59 treatment. In addition, the expression of genes included in the WNT pathway was related to the differentiation and maturation of DCs, and the production of IL-10 and IL-17 produced by PBMCs was altered.

CONCLUSIONS

Our findings illustrated that rHCA59 could enhance host immune responses by regulating the functions of goat PBMCs and DCs, which would benefit our understanding of HCA59 from parasitic nematodes contributing to the mechanism of parasitic immune evasion.