Characteristics of SARS-CoV-2 and Opisthorchis viverrini coinfections: insights into immune responses and clinical outcomes.

The effects of co-infections with SARS-CoV-2 and parasitic diseases have been little investigated in terms of immune response, disease dynamics, and clinical outcomes. This study aimed to explore the impact of co-infection with Opisthorchis viverrini and SARS-CoV-2 on the immune response concerning clinical symptoms and the severity of pulmonary abnormalities. A cross-sectional study was conducted, including healthy participants as controls, participants with opisthorchiasis, SARS-CoV-2 infection, and a co-infection group with both diseases. Characteristics of SARS-CoV-2 infection were assessed based on clinical parameters and severity of pulmonary abnormalities, whereas opisthorchiasis burden was evaluated by eggs-per-gram (EPG) counts. Immune responses were assessed by measuring levels of interferon-γ (IFN-γ), SARS-CoV-2 anti-spike receptor binding domain (RBD) IgG, and neutralizing antibody against SARS-CoV-2. In the co-infected group, clinical parameters and hospitalization rates were lower than in the SARS-CoV-2 group. Pulmonary abnormalities, such as bronchial fibrosis, were commonly observed in the SARS-CoV-2 group, leading to hospitalization in some cases. Participants with opisthorchiasis had higher IFN-γ levels than healthy individuals. IFN-γ levels were significantly lower in the co-infection group compared with the SARS-CoV-2 group (P = 0.002). There was a significant (P = 0.044) positive correlation between RBD-specific IgG and percent neutralization levels in the SARS-CoV-2 group. Levels of both were somewhat lower (not statistically significant) in the co-infection group. A negative correlation was observed between opisthorchiasis burden (EPG counts) and IFN-γ and RBD-specific IgG levels in the co-infected group. Following vaccination, the increase in IgG levels against the RBD protein was significantly lower in the co-infected group than in the SARS-CoV-2 group. These results suggest that O. viverrini infection suppresses immune responses and may lead to a reduction in severity in cases of SARS-CoV-2 co-infection.

Development of a subunit vaccine against the cholangiocarcinoma causing Opisthorchis viverrini: a computational approach.

Opisthorchis viverrini is the etiological agent of the disease opisthorchiasis and related cholangiocarcinoma (CCA). It infects fish-eating mammals and more than 10 million people in Southeast Asia suffered from opisthorchiasis with a high fatality rate. The only effective drug against this parasite is Praziquantel, which has significant side effects. Due to the lack of appropriate treatment options and the high death rate, there is a dire need to develop novel therapies against this pathogen. In this study, we designed a multi-epitope chimeric vaccine design against O. viverrini by using immunoinformatics approaches. Non-allergenic and immunogenic MHC-1, MHC-2, and B cell epitopes of three candidate proteins thioredoxin peroxidase (Ov-TPx-1), cathepsin F1 (Ov-CF-1) and calreticulin (Ov-CALR) of O. viverrini, were predicted to construct a potent multiepitope vaccine. The coverage of the HLA-alleles of these selected epitopes was determined globally. Four vaccine constructs made by different adjuvants and linkers were evaluated in the context of their physicochemical properties, antigenicity, and allergenicity. Protein-protein docking and MD simulation found that vaccines 3 was more stable and had a higher binding affinity for TLR2 and TLR4 immune receptors. In-silico restriction cloning of vaccine model led to the formation of plasmid constructs for expression in a suitable host. Finally, the immune simulation showed strong immunological reactions to the engineered vaccine. These findings suggest that the final vaccine construct has the potential to be validated by in vivo and in vitro experiments to confirm its efficacy against the CCA causing O. viverrini.

Production and immunological characterization of the novel single-chain variable fragment (scFv) antibodies against the epitopes on Opisthorchis viverrini cathepsin F (OvCatF).

BACKGROUND: Opisthorchis viverrini infection is a significant health problem in several countries, especially Southeast Asia. The infection causes acute gastro-hepatic symptoms and also long-term infection leading to carcinogenesis of an aggressive bile duct cancer (cholangiocarcinoma; CCA). Hence, the early diagnosis of O. viverrini infection could be the way out of this situation. Still, stool examination by microscopic-based methods, the current diagnostic procedure is restricted by low parasite egg numbers in the specimen and unprofessional laboratorians. The immunological procedure provides a better chance for diagnosis of the infection. Hence, this study aims to produce single-chain variable fragment (scFv) antibodies for use as a diagnostic tool for O. viverrini infection. METHODS: This study uses phage display technologies to develop the scFv antibodies against O. viverrini cathepsin F (OvCatF). The OvCatF-deduced amino acid sequence was analyzed and predicted for B-cell epitopes used for short peptide synthesis. The synthetic peptides were used to screen the phage library simultaneously with OvCatF recombinant protein (rOvCatF). The potentiated phages were collected, rescued, and reassembled in XL1-blue Escherichia coli (E. coli) as a propagative host. The positive clones of phagemids were isolated, and the single-chain variable (scFv) fragments were sequenced, computationally predicted, and molecular docked. The complete scFv fragments were digested from the phagemid, subcloned into the pOPE101 expression vector, and expressed in XL1-blue E. coli. Indirect ELISA and Western analysis were used to verify the detection efficiency. RESULTS: The scFv phages specific to OvCatF were successfully isolated, subcloned, and produced as a recombinant protein. The recombinant scFv antibodies were purified and refolded to make functional scFv. The evaluation of specific recognition of the particular epitopes and detection limit results by both computational and laboratory performances demonstrated that all three recombinant scFv antibodies against OvCatF could bind specifically to rOvCatF, and the lowest detection concentration in this study was only one hundred nanograms. CONCLUSION: Our produced scFv antibodies will be the potential candidates for developing a practical diagnostic procedure for O. viverrini infection in humans in the future.

Production and characterization of monoclonal antibodies against highly immunogenic Opisthorchis viverrini proteins and development of coproantigen detection.

Opisthorchis viverrini and other foodborne trematode infections are major health concerns in the Greater Mekong Subregion. Currently, the gold-standard diagnostic method for opisthorchiasis is conventional stool examination for the presence of parasite eggs. This method lacks sensitivity and needs an experienced technician. We therefore produced monoclonal antibodies to highly immunogenic O. viverrini proteins aiming at detecting specific antigens in the feces. In this study, BALB/C mice were immunized using semi-purified somatic antigens and spleen cells were fused with a Sp2/0 myeloma cell line. Four hybridomas (1A2, 1E12, 2C7 and 8D6) were selected and cloned due to their strong reaction against O. viverrini somatic protein, resulting in three IgM clones and one IgG2 clone. Immunohistochemistry showed that 1A2, 1E12, 2C7 and 8D6 stained the parenchyma cells, gut, tegument and muscles, respectively. Western-blot analysis revealed that only antibody 1A2 could detect coproantigen (approx. 73 kDa protein) in feces of hamsters infected with O. viverrini. The 1A2 monoclonal antibody may be of value in the diagnosis of opisthorchiasis by coproantigen detection.

Enhanced neutrophil functions during Opisthorchis viverrini infections and correlation with advanced periductal fibrosis.

Millions of people are infected with the liver fluke, Opisthorchis viverrini (OV), but only ~25% of those infected develop liver disease and even fewer develop cholangiocarcinoma. The reasons for these differential outcomes following infection are unknown but it has been proposed that differential immune responses to the parasite may play a role. We therefore measured granulocyte (neutrophil) function in OV-infected individuals, with and without advanced periductal fibrosis, to determine if these cells have a "pro-inflammatory" phenotype that may contribute to liver disease post-infection. A case-controlled study (n = 54 in each cohort) from endemic OV-infected areas of northeastern Thailand measured neutrophil functions in whole blood from non-infected (healthy controls) and OV-infected individuals with and without APF. We measured reactive oxygen species production, phagocytosis, receptor expression and apoptosis. Secreted products from OV cultures (obtained after in vitro culture of parasites) stimulated reactive oxygen species production in non-infected healthy controls, but levels were two-fold greater after OV infection (P < 0.0001); neutrophil reactive oxygen species production in individuals with APF was double that observed in those without APF (P < 0.0001). OV-infected neutrophils had elevated CD11b expression and greater phagocytic capacity, which was even three-fold higher in those with advanced periductal fibrosis (P < 0.0001). This "activated" phenotype of circulating neutrophils was further confirmed by the observation that isolated neutrophils had delayed apoptosis ex vivo. We believe this is the first study to show that circulating blood neutrophil function is enhanced following OV infection and is more activated in those with advanced periductal fibrosis. We propose that this activated phenotype could contribute to the pathology of liver disease. These data support the hypothesis of an activated innate inflammatory phenotype following OV infection and provide the first evidence for involvement of neutrophils in disease pathology.

AuNPs-LISA, an efficient detection assay for Opisthorchis viverrini (Ov) antigen in urine.

The enzyme-linked immunosorbent assay (ELISA) is currently a powerful technique for the detection of Opisthorchis viverrini antigen (OvAg) in urine samples. However, its sensitivity and analysis time need to be improved. In the present study, we aimed to improve the signal enhancing system of traditional ELISA by using gold nanoparticles (AuNPs) with peroxidase-like activity on its surface instead of the horseradish peroxidase (HRP) system. The catalytic activity of the AuNPs probe can be boosted by the gold enhancing solution and the addition of ATP. The catalytic ability of the AuNPs probe depended on the probe and the H2O2 concentration. The proposed approach can reduce the number of the traditional ELISA steps with better detection sensitivity. Interestingly, the limit of detection (LOD) of the test was 23.4 ng mL-1, substantially lower than the 93.8 ng mL-1 for the traditional ELISA. The AuNPs-LISA assay showed higher sensitivity and specificity, 93.81% and 91.34%, respectively, compared to the traditional ELISA. The proposed assay was successfully applied for the detection of OvAg in urine samples. This will provide an effective tool for the detection, control and elimination of human opisthorchiasis.

Association of Chronic Opisthorchis Infestation and Microbiota Alteration on Tumorigenesis in Cholangiocarcinoma.

Cholangiocarcinoma (CCA) is a common hepatobiliary cancer in East and Southeast Asia. The data of microbiota contribution in CCA are still unclear. Current available reports have demonstrated that an Opisthorchis viverrini (OV) infection leads to dysbiosis in the bile duct. An increase in the commensal bacteria Helicobacter spp. in OV-infected CCA patients is associated with bile duct inflammation, severity of bile duct fibrosis, and cholangiocyte proliferation. In addition, secondary bile acids, major microbial metabolites, can mediate cholangiocyte inflammation and proliferation in the liver. A range of samples from CCA patients (stool, bile, and tumor) showed different degrees of dysbiosis. The evidence from these samples suggests that OV infection is associated with alterations in microbiota and could potentially have a role in CCA. In this comprehensive review, reports from in vitro, in vivo, and clinical studies that demonstrate possible links between OV infection, microbiota, and CCA pathogenesis are summarized and discussed. Understanding these associations may pave ways for novel potential adjunct intervention in gut microbiota in CCA patients.

Recombinant Opisthorchis viverrini tetraspanin expressed in Pichia pastoris as a potential vaccine candidate for opisthorchiasis.

Opisthorchiasis affects millions of people in Southeast Asia and has been strongly associated with bile duct cancer. Current strategic control approaches such as chemotherapy and health education are not sustainable, and a prophylactic vaccine would be a major advance in the prevention of the disease. Tetraspanins are transmembrane proteins previously described as potential vaccine candidates for other helminth infections and are also found in the membranes of the tegument and extracellular vesicles of O. viverrini. Here, we investigated the potential of a recombinant protein encoding for the large extracellular loop of O. viverrini tetraspanin-2 (rOv-LEL-TSP-2) in a hamster vaccination model. Hamsters were vaccinated with 50 and 100 µg of rOv-LEL-TSP-2 produced from Pichia pastoris yeast combined with alum CpG adjuvant via the intraperitoneal route. The number of worms recovered from hamsters vaccinated with rOv-LEL-TSP-2 was significantly reduced compared to adjuvant control groups. Fecal egg output was also significantly reduced in vaccinated animals, and the average length of worms recovered from vaccinated animals was significantly shorter than that of the control group. Vaccinated animals showed significantly increased levels of anti-rOv-TSP-2 IgG in the sera after three immunizations, as well as increased levels of several T helper type 1 cytokines in the spleen including IFN-γ and IL-6 but not the Th2/regulatory cytokines IL-4 or IL-10. These results suggest that rOv-TSP-2 could be a potential vaccine against opisthorchiasis and warrants further exploration.

Vaccination of hamsters with Opisthorchis viverrini extracellular vesicles and vesicle-derived recombinant tetraspanins induces antibodies that block vesicle uptake by cholangiocytes and reduce parasite burden after challenge infection.

BACKGROUND: The liver fluke Opisthorchis viverrini infects several million people in Southeast Asia. Adult flukes live in the bile ducts of humans, where they cause hepatobiliary pathology, including cholangiocarcinoma. Here, we investigated the potential of extracellular vesicles (EVs) secreted by the fluke and defined recombinant proteins derived from EVs to generate protective immunity in a hamster vaccination-challenge model. METHODOLOGY/PRINCIPAL FINDINGS: EVs isolated from the excretory-secretory products of O. viverrini and two recombinant EV surface proteins encoding the large extracellular loops (LEL) of Ov-TSP-2 (rOv-TSP-2) and Ov-TSP-3 (rOv-TSP-3) were adjuvanted and used to vaccinate hamsters intraperitoneally followed by challenge infection with O. viverrini metacercariae. The number of adult flukes recovered from hamsters immunized with EVs, rOv-TSP-2, rOv-TSP-3 and rOv-TSP-2+rOv-TSP-3 were significantly reduced compared to control animals vaccinated with adjuvant alone. The number of eggs per gram feces was also significantly reduced in hamsters vaccinated with rOv-TSP-2 compared to controls, but no significant differences were found in the other groups. The average length of worms recovered from hamsters vaccinated with EVs, rOv-TSP-2 and rOv-TSP-3 was significantly shorter than that of worms recovered from the control group. Anti-EV IgG levels in serum and bile were significantly higher in hamsters vaccinated with EVs compared to control hamsters both pre- and post-challenge. In addition, levels of anti-rOv-TSP antibodies in the serum and bile were significantly higher than control hamsters both pre- and post-challenge. Finally, antibodies against rOv-TSP-2 and rOv-TSP-3 blocked uptake of EVs by human primary cholangiocyte in vitro, providing a plausible mechanism by which these vaccines exert partial efficacy and reduce the intensity of O. viverrini infection. CONCLUSION/SIGNIFICANCE: Liver fluke EVs and recombinant tetraspanins derived from the EV surface when administered to hamsters induce antibody responses that block EV uptake by target bile duct cells and exert partial efficacy and against O. viverrini challenge.

High macrophage activities are associated with advanced periductal fibrosis in chronic Opisthorchis viverrini infection.

Liver fluke infection caused by Opisthorchis viverrini induces several hepatobiliary conditions including advanced periductal fibrosis (APF) and cholangiocarcinoma (CCA), but >25% of the infected population develops APF and 1% develop CCA. The innate immune response is the first line of defence, and macrophages are critical regulators of fibrosis. We hypothesized that macrophages from infected individuals have different capacities to either promote or suppress periductal fibrosis. We compared phagocytic activities of macrophages of healthy individuals and O viverrini-infected individuals ± APF, and found that macrophages from infected individuals with APF ingested significantly higher numbers of beads compared with healthy controls and O viverrini-infected individuals without APF. To further investigate proteolytic activity, we monitored real-time phagosomal proteolysis of beads conjugated to DQ-BODIPY-BSA using live cell imaging. We show that macrophages from O viverrini-infected individuals with APF also have elevated phagosomal proteolysis activity, which is consistent with their increased phagocytic activity. Additionally, stimulated ROS production by blood monocytes was higher in individuals with APF compared with healthy controls and infected individuals without APF. These results suggest that during O viverrini infection, macrophages with high phagocytic and proteolytic activities together with elevated ROS production are the phenotypes that can promote tissue damage, which results in periductal fibrosis.

Immune Response to Opisthorchis viverrini Infection and Its Role in Pathology.

Human liver fluke infection caused by Opisthorchis viverrini is a major public health problem in Mekong countries such as Thailand, Laos, Cambodia, Vietnam, and Myanmar with over 10 million infected through consumption of fish containing infective metacercariae. With no tissue migration phase and living entirely within the larger secondary (intrahepatic) bile ducts, liver flukes are only exposed to a biliary mucosal immune response, while their excretory and secretory products also stimulate chronic inflammation of biliary epithelium. Neither mucosal nor tissue immune responses appear to cause parasite death or protect against newly established flukes, as evidenced by the persistence of infection for decades in the body and rapid reinfection following treatment. Experimental studies suggest that specific immune suppressive mechanisms may promote parasite persistence, therefore allowing continued secretion of parasite products that damage the biliary epithelium, both directly through mechanical damage and mitogenicity and through innate and adaptive inflammatory responses. Chronic infection is associated with several hepatobiliary diseases, specifically gallbladder and bile duct inflammation (cholecystitis and cholangitis), periductal fibrosis, and cholangiocarcinoma, the fatal bile duct cancer. Various studies have linked the chronic immune response to parasite antigens to both fibrosis and many steps in the carcinogenic process. Here, we review research-based understandings of the basic immune response to liver fluke infection and its roles in host protection and immunopathogenesis from available literature and also from recent studies conducted by the authors.

Update on Pathogenesis of Opisthorchiasis and Cholangiocarcinoma.

Infection with the food-borne liver fluke Opisthorchis viverrini causes cholangiocarcinoma (CCA). Whereas the cause of CCA in the West remains obscure, the principal risk factor in Thailand is opisthorchiasis. Here, we review recent findings on the pathogenesis of opisthorchiasis and CCA focusing on helminth molecules/toxic metabolites, host-parasite interaction, endocytosis, immunopathology/inflammatory responses, free radical production, molecular genetic alterations, and multifactorial including coinfections driving to CCA development.

Melatonin suppresses eosinophils and Th17 cells in hamsters treated with a combination of human liver fluke infection and a chemical carcinogen.

BACKGROUND: The combination of Opisthorchis viverrini (OV) infection and chemical carcinogen induces cholangiocarcinoma (CCA) in hamsters via inflammation-mediated mechanisms. Thus, suppression of inflammatory cells at the initial stages of CCA development would be of benefit. We aimed to investigate whether IL-17-producing CD4+ T cells (Th17) and CD4+ Foxp3+ T cells (Treg) are involved in the early stages of CCA genesis and can be targeted for suppression by melatonin. METHODS: Inflammation, an initial stage of CCA development, was induced in hamsters by a combination of O. viverrini infection and N-nitrosodimethylamine (NDMA) administration. Melatonin (50mg/kg) was additionally administered to one group for the 30days of the experiment. Liver tissue-resident T cells were investigated using immunostaining, western blotting, and real-time PCR. RESULTS: OV+NDMA-induced CCA tissues showed significantly higher numbers of inflammatory cells, especially eosinophils, bile duct proliferation and IL-17+ cell infiltration compared to normal livers. Expression of Foxp3 was localized in the bile duct epithelial cells, and especially in the bile duct hyperplasia. Accumulation of CD4+ and IL-17+ cells and intense staining of the Foxp3+ marker were consistent with their protein levels. Infiltration of IL-17+ inflammatory cells and Foxp3+ cells, as well as increases in their transcription expression levels, were significantly lower in the melatonin-treated group. In contrast, increased CD4+ cell infiltration and TNF-α expression were also observed through melatonin treatment. CONCLUSION: Melatonin exerts an immunomodulatory effect, suppressing eosinophils and Th17 cells and expression of Foxp3, but enhancing CD4+ cells and TNF-α. This suggests that melatonin may be used for CCA chemoprevention.

Opisthorchis felineus negatively associates with skin test reactivity in Russia-EuroPrevall-International Cooperation study.

BACKGROUND: Most studies on the relationship between helminth infections and atopic disorders have been conducted in (sub)tropical developing countries where exposure to multiple parasites and lifestyle can confound the relationship. We aimed to study the relationship between infection with the fish-borne helminth Opishorchis felineus and specific IgE, skin prick testing, and atopic symptoms in Western Siberia, with lifestyle and hygiene standards of a developed country. METHODS: Schoolchildren aged 7-11 years were sampled from one urban and two rural regions. Skin prick tests (SPT) and specific IgE (sIgE) against food and aeroallergens were measured, and data on allergic symptoms and on demographic and socioeconomic factors were collected by questionnaire. Diagnosis of opisthorchiasis was based on PCR performed on stool samples. RESULTS: Of the 732 children included, 34.9% had opisthorchiasis. The sensitization to any allergen when estimated by positive SPT was 12.8%, while much higher, 24.0%, when measured by sIgE. Atopic symptoms in the past year (flexural eczema and/or rhinoconjunctivitis) were reported in 12.4% of the children. SPT was positively related to flexural eczema and rhinoconjunctivitis, but not to wheezing. Opisthorchiasis showed association with lower SPT response, as well as borderline association with low IgE reactivity to any allergen. However, the effect of opisthorchiasis on SPT response was not mediated by IgE, suggesting that opisthorchiasis influences SPT response through another mechanism. Opisthorchiasis also showed borderline association with lower atopic symptoms. CONCLUSIONS: There is a negative association between a chronic helminth infection and skin prick test reactivity even in a developed country.

Induction of regulatory T cells by Opisthorchis viverrini.

Opisthorchis viverrini causes public health problems in South-East Asia. Recently, TGF-ß and IL-10 have been reported to increase in O. viverrini-infected hamsters but the sources of these cytokines are still unknown. In this study, the CD4+ T cells in infected hamsters were investigated. It was demonstrated that IL-4+ CD4+ T cells were significantly increased in hamster spleens and mesenteric lymph nodes (MLNs) during chronic infection. Interestingly, IL-10+ CD4+ T cells were also discovered at a significant level while Treg (T regulatory)-like TGF- ß+ CD4+ T cells were in MLNs of infected hamsters. Moreover, the CD4+ CD25+ Foxp3+ Treg cell response was significantly found both in spleens and MLNs in infected hamsters. The findings were then confirmed by development of T-cell clones against crude somatic antigens (CSAg) in immunized BALB/c mice. Five clones named TCC21, TCC23, TCC35, TCC41 and TCC108 were established. The TCC21 was found to be the TGF-ß+ CD4+ while TCC35, TCC41 and TCC108 were IL-4+ CD4+ and TCC23 was IFN-γ+ CD4+ . This TGF-ß+ CD4+ T clone showed an inhibitory function in vitro in mononuclear cell proliferation via TGF-ß-mediated mechanisms. This study indicated that O. viverrini-infected hamsters could induce TGF-ß+ CD4+ Treg-like cells. The CSAg-specific Tregs secreted high TGF-ß, and limited immune cell proliferation.

Serum Antibody Ig G and Ig M Titers for Opisthorchis felineus Correlate with Eggs in Faeces--a Comprehensive Study in Chuvash Republic, Russia.

The Cholangiocarcinoma is a. The risk of development of cholangiocarcinoma, generally a rare type of a liver tumor, increases during infection of Opisthorchiasis. For this reason the timely detection of Opisthorchiasis is important for Cholangiocarcinoma prevention. There are many studies which concern the detection of pathogenesis of Opisthorchis viverrini infection but a little known about Opisthorchis felineus. In this study we investigate a correlation of the eggs which are found in a faeces and are comparable with a serum Ig G and Ig M antibody level that were detected with ELISA test in a large group of patients. The result is showing positive correlation between evidence of the Opisthorchis felineus eggs that were found in a faeces and antibody Ig G and Ig M level in a serum. Moreover the combination of two methods can improve the Opisthorchiasis diagnostic: the serum antibody and faeces investigation of eggs.

Immunodiagnosis of opisthorchiasis using parasite cathepsin F.

Opisthorchis viverrini, a food-borne trematode parasite endemic in the lower Mekong countries, is conventionally diagnosed by stool examination. However, parasitological stool-based diagnosis can be unreliable in light infections. The goal of this study was to develop the immunodiagnosis of opisthorchiasis using cathepsin F cysteine protease of O. viverrini in both indirect and sandwich ELISA assays. A recombinant O. viverrini cathepsin F (rOv-CF) of 40 kDa was expressed in E. coli strain BL21 (DE3), affinity purified, and deployed in ELISA assays. Human sera from 272 cases were investigated by indirect rOv-CF-based ELISA. Positive antibody response to rOv-CF was found in 137 out of 272 cases (50.37 %) using a cutoff OD (0.400) determined by ROC analysis. In comparison to parasitological stool examined for fluke eggs, the gold standard, the rOv-CF indirect ELISA showed a sensitivity and specificity of 62.1 and 84.05 %, respectively. Serum antibody levels correlated well with egg counts per gram feces (EPG) (P < 0.001). In addition, chicken IgY antibody raised against rOv-CF was tested in a sandwich ELISA for detection of coproantigen in the feces of experimentally infected hamsters. The sandwich ELISA using this chicken IgY in combination with rabbit antibody to O. viverrini somatic antigens showed sensitivity and specificity of 93.3 and 78.57 %, respectively. Together, these findings indicated the potential of rOv-CF for diagnosis of opisthorchiasis, including for uses with chicken IgY for detection of coproantigens of O. viverrini.

A Promising Serum Autoantibody Marker, Anti-Heat Shock Protein 90α, for Cholangiocarcinoma.

The present study was designed to investigate cholangiocarcinoma (CCA) antibodies in hamster serum. Hamster CCA cell lines were processed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. A candidate biomarker was confirmed by immunoprecipitation and western blot, and was further analyzed using ELISA and sera from normal control hamsters, hamsters with opisthorchiasis and hamsters with various stages of CCA, as well as from CCA patients and healthy individuals. One candidate marker was identified as HSP90α, as indicated by a high level of anti-HSP90α in hamster CCA sera. It was found that the levels of anti-HSP90α were specifically elevated in the sera of hamsters with CCA compared with other groups and progressively increased with the clinical stage. At the cut-off point of 0.4850 on the receiver operating characteristic curve, anti-HSP90α could discriminate CCA from healthy control groups with a sensitivity of 76.2%, specificity of 71.4% and total accuracy 75.5%. In the present study, we have shown that anti-HSP90α may be a potential useful serum biomarker to discriminate CCA cases from healthy persons.

Plasma IgG autoantibody against actin-related protein 3 in liver fluke Opisthorchis viverrini infection.

Opisthorchiasis secondary to Opisthorchis viverrini infection leads to cholangiocellular carcinoma through chronic inflammation of the bile ducts and possibly inducing autoimmunity. It was hypothesized that plasma autoantibodies directed against self-proteins are biomarkers for opisthorchiasis. Plasma from patients with opisthorchiasis was tested using proteins derived from immortalized cholangiocyte cell lines, and spots reacting with plasma were excised and subjected to LC-MS/MS. Seven protein spots were recognized by IgG autoantibodies, and the highest matching scored protein was actin-related protein 3 (ARP3). The antibody against ARP3 was tested in plasma from 55 O. viverrini-infected patients, 24 patients with others endemic parasitic infections and 17 healthy controls using Western blot and ELISA. Immunoreactivity against recombinant ARP3 was significantly more prevalent in opisthorchiasis compared to healthy controls at Western blotting and ELISA (P < 0.05). Plasma ARP3 autoantibody titres were also higher in opisthorchiasis compared to healthy individuals (P < 0.01) and other parasitic infections including Strongyloides stercoralis (P < 0.001), echinostome (P < 0.05), hookworms (P < 0.001) and Taenia spp. (P < 0.05). It was further characterized in that the ARP3 autoantibody titre had a sensitivity of 78.18% and specificity of 100% for opisthorchiasis. In conclusion, it may be suggested that plasma anti-ARP3 might represent a new diagnostic antibody for opisthorchiasis.

[Food sensitization in children with Opisthorchis felineus invasion].

AIM: To determine the mechanism of food sensitization in children with chronic Opisthorchis felineus invasion. PATIENTS AND METHODS: During the epidemiological study the groups of patients (7-10 years) with chronic opisthorchiasis (n = 237) and children without chronic opisthorchiasis (n = 496) were formed. The investigation included interviewing of parents/guardians, measurement of total IgE, specific IgE to food allergens and component-resolved diagnostic, real-time PCR in stool samples. RESULTS: The chronic opisthorchiasis invasion in children is associated with reduced risk of food sensitization, compared with non-infected group (9.7 vs 16.94%, OR = 0.53; 95% CI 0.31-0.88; p = 0.01). Opisthorchiasis of high intensity negatively correlated with increased level of specific IgE to food allergens in serum (OR = 0.46; 95% CI 0.24-0.91; p = 0.023). The association between level of total IgE and intensity of opisthorchiasis combinated with food sensitization was found. The sensitization to allergens class I (cyp c1, cor a11, gal d2, pru p3) is more prevalent in patients with opisthorchiasis, in uninfected children the sensitization to bet v1-homologues (mal d1, pru p1, cor a1, ara h8) is most common. CONCLUSIONS: The epidemiological data on the effect of the Opisthorchis felineus invasion on mechanisms of food sensitization in children were obtained.