• Parasites, Hosts and Diseases
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• v.56 no.1
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• pp.41-48
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• 2018

The infection status of Clonorchis sinensis metacercariae (CsMc) was examined in freshwater fish from a highly prevalent site, Wicheon (a branch of Nakdong-gang), which is located in Gunwi-gun, Gyeongsangbuk-do, the Republic of Korea. Total 1,162 fish in 32 species were examined by the artificial digestion method through 6 years. CsMc were detected in 720 (67.5%) out of 1,067 fish (26 spp.) and their density was 610 per fish infected. In the susceptible gobioninid fish group, i.e., Pungtungia herzi, Squalidus gracilis majimae, Squalidus japonicus coreanus, Sarcocheilichthys variegatus wakiyae and Pseudorasbora parva, all of 323 fish were infected with an average of 1,310 CsMc. Total 23 (95.8%) gobioninid fish, i.e., Pseudogobio esocinus, Abbottina springeri, Hemibarbus longirostris, Microphysogobio koreensis, and Microphysogobio jeoni, were infected with 127 CsMc in average. In the acheilognathinid fish (bitterlings) group, the prevalence was 77.0%, and the density was 50 CsMc per fish infected. In the rasborinid fish (chubs) group, i.e., Zacco platypus, Zacco temminckii, Zacco koreanus, and Opsariichthys uncirostris amurensis, 147 (36.5%) out of 403 fish examined were infected with 15 CsMc in average. The susceptibility indices of CsMc were 412 in the overall positive fish group, 1,310 in the gobioninid group-1, 122 in the gobioninid group-2, 38.5 in the acheilognathinid group, and 5.5 in the rasborinid fish group. Conclusively, it was confirmed that CsMc are highly prevalent in fish from Wicheon, and their infection tendency varied according to the subfamily groups in Cyprinidae fish hosts.

• Parasites, Hosts and Diseases
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• v.47 no.4
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• pp.359-367
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• 2009

Paramyosin is a myofibrillar protein present in helminth parasites and plays multifunctional roles in host-parasite interactions. In this study, we identified the gene encoding paramyosin of Clonorchis sinensis (CsPmy) and characterized biochemical and immunological properties of its recombinant protein. CsPmy showed a high level of sequence identity with paramyosin from other helminth parasites. Recombinant CsPmy (rCsPmy) expressed in bacteria had an approximate molecular weight of 100 kDa and bound both human collagen and complement 9. The protein was constitutively expressed in various developmental stages of the parasite. Imunofluorescence analysis revealed that CsPmy was mainly localized in the tegument, subtegumental muscles, and the muscle layer surrounding the intestine of the parasite. The rCsPmy showed high levels of positive reactions (74.6%, 56/75) against sera from patients with clonorchiasis. Immunization of experimental rats with rCsPmy evoked high levels of IgG production. These results collectively suggest that CsPmy is a multifunctional protein that not only contributes to the muscle layer structure but also to non-muscular functions in host-parasite interactions. Successful induction of host IgG production also suggests that CsPmy can be applied as a diagnostic antigen and/or vaccine candidate for clonorchiasis.

• Parasites, Hosts and Diseases
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• v.40 no.2
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• pp.83-88
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• 2002

The 8 kDa antigenic protein of Clonorchis sinensis was partially purified by ammonium sulfate precipitation and subsequently by a column chromatographic steps. The purified protein was separated into 7 and 8 kDa protein bands through SDS-tricine gel electrophoresis, while the protein was fecund to migrate to a 8 kDa band in 7.5-15% SDS-PAGE. The molecular weight of the antigen was estimated to be 110 kDa by Superose 6 HR 10/30 gel filtration. The purified antigen strongly reacted with the human sera of clonorchiasis. The hyperimmune sera of BALB/c mice immunized against the 8 kDa protein were reacted with both the crude extract and the excretory-secretory product of adult worms, but not with the metacercarial extract. Immunohistochemical staining demonstrated that the protein was distributed to the tegument and subtegumental cells and also to the seminal receptacle. The present findings suggest that the 8 kDa protein is a partition of the multicomplek protein originating from various organs of adult C. sinenis, and that it is composed of several 7 and 8 kDa proteins.

• Parasites, Hosts and Diseases
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• v.42 no.1
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• pp.7-17
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• 2004

This study describes an evaluation of the sonographic, cholangiographic, pathological, and immunological findings, and the protective effect shown by rats reinfected with Clonorchis sinensis. Eight experimental rat groups were, namely, a normal control, a primary infection control, a reinfection I (reinfection 7 week after treatment following 3-week infection), a reinfection II (reinfection 2 week after treatment following 8-week infection), a reinfection III (exploration of the intrahepatic bile ducts 1 week after reinfection 4 week after treatment following 4-week infection), a superinfection, a secondary infection control, and an infection following immunization group. Sonographic and cholangiographic findings showed moderate or marked dilatation of the bile duct confluence in the primary infection control, reinfection II, and secondary infection control groups. Juvenile worms survived in the intrahepatic bile ducts 1 week after reinfection following treatment in the reinfection III group. It was concluded that reinfecting juvenile worms found during the first week following reinfection failed to survive or grow further. Anatomical, pathophysiological, or immunological changes may induce protection from reinfection in rats.

• Korean Journal of Veterinary Pathology
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• v.6 no.1
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• pp.41-48
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• 2002

Oval cell is considered as facultative precursor cells for both hepatocytes and biliary cells, as well as origin of hepatocellar and cholangiocellular carcinoma (CCC) during carcinogenesis or toxic liver injury. To clarify the cellular origin or differentiation of cholagiocarcinogensis, the fate of carcinogen-induced oval cells was pathologically and phenotypically chased in Syrian golden hamster liver after Clonorchis sinensis (CS) infection which would give rise to a promoting effect. Two week treatment of hamsters with 0.005% diethylnitrosamine (DEN) followed by 2 week treatment of 1% 2-acetylaminofluorene (AAF) under choline deficient diet resulted in massive proliferation of BrdU labeleed and PCNA positive oval cells showing various distinct morphology, histochemical and immunohistochemical phenotypes for GGT, cytokeratin 19 and OV-6. Oval cells also frequently form ductular-like structures or phenotypically show hepatocyte-like characteristics. After CS infection, the oval cells showed sequential morphological changes to atypicl proliferating bile ductules and all hamsters thereafter developed well differentiated and anaplastic CCC at 16 week after CS infection. In electron microscopy, some bile ductules were constructed by intermediate oval cells and bile ductular cells surrounded by basement membrane. The results of this study strongly suggest that CCC developed in the present study were originated from hepatic stem-like oval cells, supporting the theory of stem cell origin of cancers. In addition, this hamster model would be valuable for the molecular mechanistic study during chemical-triggered cholangiocarcinogenesis.

• Parasites, Hosts and Diseases
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• v.25 no.2
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• pp.110-122
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• 1987

The rabbits were infected with Clonorchis sinensis and were treated with praziquantel at the dose of $50{\;}mg/kg{\times}2회{\times}2$ days after 1,2,4,8 weeks and 7 months from the infection. Their livers were observed histopathologically 1, 4 and 12 weeks after treatment. The findings are summarized as below. 1. The changes of the liver in control rabbits were relatively mild until 2 weeks after infection. However, widening and thickening of bile ducts, proliferation of biliary epithelium and periductal fibrosis were moderate after 4 weeks from infection and those changes were severe after 8 weeks and 7 months. Goblet cell metaplasia was found after 8 weeks from infection. 2. The mild changes of 2-week infection group were completely recovered by 4 weeks after the treatment. In the groups of 4 or more weeks after infection, the changes of bile ducts became milder in the degree after the treatment, but were still found 12 weeks after the treatment. As the infection duration was passed, more severe changes were observed after the treatment. In this context, it is concluded that the liver changes of acute clonorchiasis in the early two weeks are reversible by treatment while chronic biliary epithelial changes are irreversible. Therefore, early treatment should be recommended as possible to minimize the remaining histopathological changes of liver in clonorchiasis.

• Parasites, Hosts and Diseases
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• v.29 no.4
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• pp.371-380
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• 1991

The effects of peritoneal exudate cells(PEC) and sera of athymic nude and DS mice infected with Clonorchis sinensis metacercariae or sensitized by injection of metabolic products into footpad on transfer of immunity against the fluke to the syngeneic mice were studied. There was no significant difference in eggs per gram pattern between the sensitized and control groups, and between nude and DS mice. However, the worm burdens were slightly greater in nude mice than in DS mice. Also, a few plaque forming cells were found in only DS mice given PEC and serum from Group II DS mice. In the light of these results, it is likely that PEC and sera of nude or DS mice which are deficient, at least partially, in the cellular immune system are unable to transfer immunity against C. sinensis to syngeneic recipients.

• Parasites, Hosts and Diseases
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• v.57 no.2
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• pp.145-152
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• 2019

The infection status with Clonorchis sinensis metacercariae (CsMc) was examined in freshwater fishes from Yangcheon (a branch of Gyeongho-gang), which is located in Sancheong-gun, Gyeongsangnam-do, the Republic of Korea. Total 2,201 fishes in 26 species were examined by the artificial digestion method through 7 years. CsMc were detected in 1,171 (53.2%) fishes in 21 spp. (80.8%) and their density was 85 per fish infected. Total 532 (99.6%) out of 534 Pungtungia herzi (index fish) examined were infected with 147 CsMc per fish infected. Metacercarial densities in this fish were highest in 2015 (179 CsMc), followed by 2012 (168), 2013 (152), 2016 (145), 2014 (114), and 2017 (89) respectively. In the gobioninid fish group, i.e., P. herzi, Sarcocheilichthys spp., Squalidus spp., Pseudogobio esocinus, Hemibarbus longirostris, and Hemibarbus labeo, 841 (92.7%) fishes were infected with 117 CsMc per fish infected. Total 250 (54.7%) acheilognathinid fish (bitterlings), Acheilognathus spp. and Acanthorhodeus spp. were infected with 5.8 CsMc. In the rasborinid fish (chubs) group, i.e., Zacco platypus, Zacco temminckii, and Zacco koreanus, 77 (13.7%) out of 563 fish examined were infected with 2.4 CsMc in average. The susceptibility indices of CsMc were 49.09 in the overall positive fish group, 104.15 in the gobioninid group, 3.17 in the acheilognathinid group and 0.35 in the rasborinid fish group respectively. Only 1 CsMc was detected in 3 fish species, Coreoperca herzi, Channa argus, and Lepomis macrochirus, respectively. Conclusively, it was confirmed that CsMc are moderately prevalent in fishes from Yangcheon in Sancheon-gun, Gyeongsangnam-do, Korea.

• Parasites, Hosts and Diseases
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• v.59 no.1
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• pp.97-101
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• 2021

The infection status with Clonorchis sinensis metacercariae (CsMc) was examined in freshwater fishes from Yongjeon-cheon (a branch of Nakdong-gang) located in Cheongsong-gun, Gyeongsangbuk-do, the Republic of Korea (Korea). A total of 750 fishes in 19 species were examined by the artificial digestion method for 2 years (2019 and 2020). CsMc were detected in 378 (51.4%) out of 735 fishes in 14 species (73.7%), and the infection intensity was 666 per fish infected. In 2019, CsMc were found in 172 (68.0%) out of 253 fishes in 10 species, and the infection intensity was 565 per fish infected. In 2020, CsMc were detected in 206 (62.2%) out of 331 fishes in 10 species, and the infection intensity was 751 per fish infected. The other zoonotic trematode, ie. Metagonimus spp., Centrocestus armatus, Echinostoma spp. and Clinostomum complanatum, metacercariae were also detected in fishes from the survey streams, but their endemicities were relatively low. Conclusively, it was first confirmed that CsMc are highly endemic in fishes from Yongjeon-cheon in Cheongsong-gun, Gyeongsangbuk-do, Korea.

• Parasites, Hosts and Diseases
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• v.60 no.4
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• pp.255-259
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• 2022

Heliminthic paramyosin is a multifunctional protein that not only acts as a structural protein in muscle layers but as an immune-modulatory molecule interacting with the host immune system. Previously, we found that paramyosin from Clonorchis sinensis (CsPmy) is bound to human complement C9 protein (C9). To analyze the C9 binding region on CsPmy, overlapping recombinant fragments of CsPmy were produced and their binding activity to human C9 was investigated. The fragmental expression of CsPmy and C9 binding assays revealed that the C9 binding region was located at the C-terminus of CsPmy. Further analysis of the C-terminus of CsPmy to narrow the C9 binding region on CsPmy indicated that the region flanking ⁷³¹Leu-⁷⁸⁰Leu was a potent C9 binding region. The CsPmy fragments corresponding to the region effectively inhibited human C9 polymerization. These results provide a precise molecular basis for CsPmy as a potent immunomodulator to evade host immune defenses by inhibiting complement attack.