Search

• Characterized infectivity of muscle larvae during the early stages of infection. • Th2-predominant immune response was induced in Trichinella spiralis infection. • The body weight of infected pigs compared with the control group was increased. • Anti- Trichinella spiralis IgM antibody was detected earlier than IgG antibody. The objective of the present study was to investigate the infectivity and antibody response of four Trichinella species (Trichinella spiralis , Trichinella britovi , Trichinella pseudospiralis and Trichinella murrelli) in experimentally infected pigs. A total of 120 Large White pigs (30 animals per group) were inoculated with 10,000 muscle larvae (ML) of T. spiralis , T. britovi , T. pseudospiralis , and T. murrelli. The pigs were sacrificed at 12–21 days post-infection (dpi) to examine the viability and infectivity of ML. A total of 54 Large White pigs (6 animals per group) were inoculated with 25, 50, 100, 200, 400, 600, 800, 1000 and 10,000 T. spiralis ML. The pigs were sacrificed, and the average numbers of larvae per gram (lpg) from six different muscle tissues were calculated at 120 dpi. The results showed that the larvae first be detectable for T. spiralis , T. britovi , and T. pseudospiralis at 16 dpi, 17 dpi, and 16 dpi, respectively. Viable larvae and average lpg were significantly increased with time from 17 to 21 dpi. The T. spiralis ML burden was dependent of the inoculation dose with an average lpg of 0.003, 0.005, 0.007, 0.17, 0.82, 2.89, 4.90, 28.30 and 226.18, respectively. The IgG antibody response was dose-dependent to generate and increased throughout the experimental period. And the IgG1 isotype was significantly higher than IgG2a, which meant that T. spiralis infection induced the Th2 immune response. The time of detecting IgM antibodies was significantly earlier than IgG antibody detection. These results provide important information in the primary characterization of pigs infected with Trichinella. [ABSTRACT FROM AUTHOR]

Abstract Background Therapeutic potential of helminth have been shown to have a protective effect on immune-mediated diseases such as Crohn's disease (CD), which is associated with increased production of T helper cell type 1. However, helminth therapy is unacceptable to patients due to side-effects and the fear of parasites. As helminths regulate the cellular immune responses through innate cells such as dendritic cells (DCs), cellular immunotherapy has been considered a therapeutic option to treat CD. Methods Bone marrow-dendritic cells were generated, enriched and treated with Trichinella spiralis muscle larval excretory/secretory products (Ts -MLES). DCs maturation was measured by flow cytometry and cytokine production of DCs were measured by ELISA. Colitis was generated by intrarectal administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS) solution. For adoptive transfer, Ts -MLES treated-DCs injected intravenously 24 h prior to TNBS challenge. Disease activity index (DAI) including weight loss, diarrhea, and bloody stool were measured. Colon segments were stained with hematoxylin and eosin (H.E.) and periodic acid schiff (PAS) staining for histological damage scoring. The relative mRNA expression of cytokines in colon was analyzed by RT-PCR. Cytokine production in colon was measured by ELISA. Splenocytes were separated and cytokine profiles including Th1 (IFN-γ), Th2 (IL-4, IL-13), and Treg subsets (IL-10, TGF-β) were analyzed by flow cytometry. Results Ts -MLES regulated the maturation and cytokine production of DCs. Ts -MLES -DC ameliorated the severity of the TNBS-induced colitis. In the colon and the spleen, Ts -MLES-DC decreased IFN-γ (Th1) significantly and increased Th2 (IL-4, IL-13)- and Treg (IL-10, TGF-β)- related cytokines. Conclusions Ts -MLES-DC ameliorated the severity of the TNBS-induced colitis through decreasing IFN-γ. Ts -MLES-DC skewed the Th1-mediated response toward the Th2 type and regulatory T cell response. Highlights • T. spiralis MLES (Ts -MLES) regulated DCs phenotype. • Ts -MLES-DC ameliorated the severity of the TNBS-induced colitis • Ts -MLES-DC inhibited Th1 immune response while enhancing the Th2 and Treg immune response in TNBS-induced colitis in vivo. [ABSTRACT FROM AUTHOR]

The excretory-secretory product (ESP) of Trichinella spiralis (T. spiralis) has been reported to inhibit the growth of various tumor cells, but the mechanism is not yet clear. To explore the effect and mechanism of ESP on liver cancer cells, tumor models were established with H22 cells and then infected with T. spiralis. The results showed that the growth of tumors in mice infected with T. spiralis was significantly inhibited. ESP from adult worms or muscle larvae were then incubated with H22 cells in vitro , and it was found that the ESP could inhibit cell proliferation and promote apoptosis. Subsequently, apoptosis-related proteins in stimulated H22 cells were evaluated, and ESP was found to induce cell apoptosis through the mitochondrial pathway. Additionally, Th-related cytokines were investigated in vivo , and the results showed that the levels of Th1 cytokines were significantly increased in the early stage of T. spiralis infection, while Th2 cytokines increased later than Th1 cytokines, implying that Th1 cytokines with antitumor effects may play a role in inhibiting tumor growth at early stage. In short, ESP can directly induce tumor cell apoptosis and indirectly inhibit tumor cell growth through the host immune system, which may be the antitumor mechanism of T. spiralis infection. [ABSTRACT FROM AUTHOR]

• Nod-like receptor pyrin domain containing 3 (NLRP3) expression is elevated in CD4+ T cells at 7 and 14 dpi. • NLRP3 participates in the control of the Th2 immune response during Trichinella spiralis infection. • NLRP3 influences the Th2 cell-mediated host defenses against Trichinella spiralis. The inflammasome is a key line of immune defense against invading infectious pathogens. However, knowledge of the role of nod-like receptor pyrin domain containing 3 (NLRP3) in Trichinella spiralis infection which characteristically induces T-helper 2 (Th2) immune responses is sparse. In this study, we investigated the role of NLRP3 in the protection against T. spiralis infection through the Th2 immune response. We show that NLRP3 expression in CD4+ T cells was significantly increased at 7 days post-infection of T. spiralis. Compared to wild-type (WT) CD4+ T cells, the expression of IL-4 mRNA was reduced in NLRP3−/− CD4+ T cells, however, the expression of IFN-γ mRNA was comparable between the two groups. Consistently, ELISA and flow cytometry analysis showed that NLRP3−/− CD4+ T cells secreted lower levels of IL-4 than CD4+ T cells from WT mice, whilst the levels of IFN-γ secreted by NLRP3−/− CD4+ T cells were of similar levels to those secreted by WT CD4+ T cells. In addition, we observed a significant reduction of IL-4 and IL-13 by ELISA in NLRP3 −/− mice at 1, 2 and 4 weeks post-infection. Furthermore, we found that adult worm survival was substantially prolonged and muscle larvae burden was significantly increased in NLRP3 −/− mice. We further show that NLRP3 promotes the host defense against T. spiralis through its participation in the differentiation of Th2 cells. These findings provide novel insights into parasite expulsion and highlight the importance of NLRP3 in the host defense against T. spiralis. [ABSTRACT FROM AUTHOR]

• Trichinella spiralis extracellular vesicles (Ts -EVs) intervened with the inflammatory responses of DSS-induced colitis in mice; • Ts -EVs inhibited M1 macrophage polarization in DSS-induced colitis; • Ts -EVs targeted both the MAPK and NF-κB pathways to regulate host immunity in DSS-induced colitis. Extracellular vesicles (EVs) are membranous containers released by cells that are powerful agents of intercellular communication. EVs have been described for various parasites and are associated with tissue inflammation. Several studies have demonstrated that parasite EVs can have either pro- or anti-inflammatory impacts, depending on the type of parasite. To evaluate the immunomodulatory properties of EVs produced by Trichinella spiralis (T. spiralis), we established a mouse model with dextran sulphate sodium (DSS)-induced colitis. The muscle larvae of T. spiralis were cultured in vitro and the released EVs were isolated by ultracentrifugation. T. spiralis EVs (Ts -EVs) were characterized according to morphology, size and constituent surface proteins (CD63, Enolase and Hsp70). Mice were treated with water containing 3% DSS after last intraperitoneal injection of Ts -EVs. Disease activity index (DAI), macroscopic and histopathological scores of Ts -EVs group was lower than DSS group. And Ts -EVs prevented the increase in the expression of TNF-α, IFN-γ, IL-17A and IL-1β observed in the colon of DSS-treated mice. In contrast, upregulation of IL-4, IL-10, TGF-β and IL-13 expression was detected in Ts -EVs+DSS group. In addition, Ts -EVs increased the infiltration of alternatively activated (M2) macrophages into the colon. The expression of CD206 (M2 marker) in the mesenteric lymph nodes (MLN) of mice with colitis increased in Ts -EVs+DSS group. Furthermore, Ts -EVs interfered with both the NF-κB and MAPK signalling pathways. Taken together, our findings demonstrate that Ts -EVs can affect the development of inflammation in DSS-induced colitis by inhibiting M1 macrophage polarization, due to their immunomodulatory ability. [ABSTRACT FROM AUTHOR]

• The recombinant serine protease from newborn larval stage (NBL-SP) of trichinella spirails was expressed, purified and the endotoxin in NBL-SP was removed;. • NBL-SP alleviated the severity of TNBS-induced colitis in mice;. • NBL-SP skewed the Th1 and Th17 response induced by TNBS towards the Th2 and treg response. Inflammatory bowel disease (IBD) is a complex immune-mediated disease of gastrointestinal tract that is mainly driven by Th1/Th17 immune response. "Helminth therapy" has emerged, and helminth-derived immunoregulatory molecules are being used as safe and new therapeutic antigens for IBD. Recombinant serine protease (SP) from newborn Trichinella spiralis (T. spiralis) larvae (NBL) was expressed and purified. BALB/c mice were immunized with NBL-SP at 100 µg three times at an interval of 5 days. Experimental colitis was induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) administration. The disease activity index (DAI) and macroscopic and microscopic scores of the colon were assessed to identify the effect of NBL-SP on experimental colitis. Cytokine production in the serum was analysed by meso scale discovery (MSD). Cytokine production in the colon was detected by ELISA. CD4+ T cell differentiation was measured by flow cytometry. NBL-SP alleviated TNBS-induced colitis in mice. The DAI, macroscopic and microscopic scores and colon length all showed a positive intervention effect of NBL-SP on experimental colitis. NBL-SP can weaken the increase in IFN-γ, TNF-α and IL-17 production as well as CD4+ IFN-γ+ T cell and CD4+IL-17+ T cell populations induced by colitis. Furthermore, the levels of Th2-related cytokines (IL-4, IL-5) and regulatory cytokines (IL-10, TGF-β) were elevated meanwhile the ratio of regulatory T cells (Tregs) and CD4+ IL-4 + T cells were increased by NBL-SP. NBL-SP of T. spiralis had a potential protective effect against IBD. NBL-SP skewed the Th1 and Th17-mediated response towards the Th2 and Treg response. [ABSTRACT FROM AUTHOR]

• rTs-ADSp-7 alleviated the severity of TNBS-induced colitis. • rTs-ADSp-7 increased the population of Th2 and Treg cells in TNBS-induced colitis mice. • rTs-ADSp-7 protein has the potential to treat colitis or other Th1 immune-mediated diseases. Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD), is a chronic autoimmune disease. At present, worms and their products has been shown to have protective effects on immune-mediated diseases. Therefore, we aimed to investigate the effect of the recombination Trichinella spiralis (T. spiralis, Ts) adult serine protease-like protein r Ts -ADSp-7 on a 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced CD mouse model. Colitis was induced by intrarectal administration of a TNBS solution. The disease activity index (DAI), which included weight loss, diarrhoea, and bloody stool, was measured. Colon segments were stained with haematoxylin and eosin (H.E.) for histopathological score. Cytokine release in the serum was analysed by meso scale discovery (MSD). Cytokine release in the colon was detected by ELISA. Splenocytes were separated, and the cytokine profiles of Th1 (IFN-γ), Th2 (IL-4), Th17 (IL-17A) and Treg cells were analysed by flow cytometry. Our result showed that rTs-ADSp-7 reduced the clinical disease activity of TNBS-induced colitis in mice. In addition, we found that r Ts -ADSp-7 reduced the production of Th1- and Th17-related cytokines while upregulating the expression of Th2- and Treg-related cytokines in TNBS-induced colitis mice. r Ts -ADSp-7 also increased the population of Th2 and Treg cells in TNBS-induced colitis mice. r Ts -ADSp-7 alleviated the severity of TNBS-induced colitis while balancing the CD4+ T cell immune response. r Ts -ADSp-7 has therapeutic potential for colitis treatment and can be used as a helminth-derived protein therapy for CD or other Th1 immunity-mediated diseases. [ABSTRACT FROM AUTHOR]

• SERS combined with PCA-LDA has great potential in trichinellosis detection. • PCA-LDA analyses achieved a high diagnostic accuracy. • The ROC curve illustrated the performance of PCA-LDA analyses and the value is 0.977. Based on blood serum surface-enhanced Raman spectroscopy (SERS) analysis, this paper proposed a simple and unlabeled non-invasive serum detection for T. spiralis infection. Serum samples were collected and analyzed from 40 rats at 0 days post infection (dpi) (normal rats), 19 uninfected rats, and 16 rats infected with T. spiralis at 28 dpi, using SERS measurements. Multivariate statistical techniques, such as linear discriminant analysis (LDA) and principal components analysis (PCA), were used to analyze and identify the obtained blood serum SERS spectra. The diagnosis algorithms, based on PCA-LDA, achieved a diagnostic sensitivity of 87.5%, a specificity of 94.7%, and an accuracy of 91.4% for separating the samples infected with T. spiralis from the control samples. This exploratory study demonstrated that colloidal Ag NPs-based SERS serum analysis technique combined with PCA-LDA has a great potential in improving the detection of T. spiralis infection and onsite screening. [ABSTRACT FROM AUTHOR]