• Parasites, Hosts and Diseases
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• v.36 no.3
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• pp.183-190
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• 1998

A cDNA expression library of Clonorchis sinensis adult worm was constructed, and screened out immunologically. One clone, pBCs31, was selected ill view of its predominant reactivity with an experimentally infected rabbit serum. Recombinant C. slnensis antigen iIi 28 kDa as a if-falactosidase fusion protein produced in EscherichiG coli was identified by immunoblot analysis. The cloned gene was composed of 16 copies or a 30 base pair repeat and an additional 320 bases. The deduced amino acid seqiLence of the tandem repeat was AQPPKSGDGG. On RNA slot blot analysis, C. sinensis adult worm RNA showed a positive reaction with the cloned gene Enzyme-linked immunosorbent assay using a purified recombinant antigen of pBCs31 showed higtl specificity for diagnosis of clonorchiasis.

• Journal of Life Science
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• v.30 no.11
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• pp.1012-1020
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• 2020

Remicade is a therapeutic biosimilar natural antibody in which the mouse variable domain has been linked to the human constant domain. It is a chimeric monoclonal antibody specific to tumor necrosis factor-alpha (TNF-α) and has been developed for the treatment of rheumatoid arthritis. To investigate the biological activity of the Remicade antibody, we carried out a bioinformatics study using a protein data bank to characterize the TNF-α antigen binding mechanism of the Remicade natural antibody. Because the production of the Remicade antibody is often limited by genetic instability of the natural antibody-producing cell, we generated a Remicade single-chain variable domain fragment antibody (Remicade) in which a heavy chain variable domain (VH) is joined with a light chain variable domain (VL) by a polypeptide linker. Furthermore, Remicade was fused to a leucine zipper (RemicadeScZip) for higher production and higher antigen-binding activity than Remicade. The Remicade and Remicade ScZip were expressed in Escherichia coli and purified by a Ni⁺-NTA-agarose column. As expected, the purified proteins had migrated as 28.80 kDa and 33.96 kDa in sodium dodecyl sulfate-polyacrylamide electrophoresis. The TNF-α antigen binding activity of Remicade was not observed by ELISA and western blot. In contrast, RemicadeScZip showed antigen-binding activity. Additional bio-layer interferometry analysis confirmed the antigen-binding activity of RemicadeScZip, suggesting that the leucine zipper stabilized the folding of RemicadeScZip in a denatured condition and improved the TNF-α antigenbinding activity.

• The Journal of the Korean Society for Microbiology
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• v.34 no.6
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• pp.555-559
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• 1999

The 38 kDa protein of Mycobacterium tuberculosis, which was known previously as antigen 5, has been extensively used in the serodiagnosis of tuberculosis. In an attempt to develop and evaluate a serodiagnostic test using the antigen, we expressed the 38 kDa protein in BCG and its seroreactivity was compared to that expressed in Escherichia coli. The coding region of the 38 kDa protein was amplified by PCR, and the gene was cloned into a Mycobacterium-E. coli shuttle expression vector pYMC-his and pQE30 expression vector and expressed in BCG and E. coli, respectively. Both recombinant 38 kDa proteins showed strong seroreactivity against pooled serum from tuberculosis patients. There was no significant difference in seroreactivity between the two recombinant antigens in sera from the far advanced tuberculosis patients. However, of 25 tuberculosis patients graded as "minimal" by chest X-ray, 5 (20.0%) were seropositive by r38 kDa expressed in E. coli, while 8 (32.0%) by that expressed in BCG. Likewise, higher seroreactivity by r38 kDa expressed in BCG was found in sera from the moderately advanced tuberculosis. This study thus indicates that the recombinant 38 kDa expressed in BCG is more effective than that expressed in E. coli in detecting antibodies to the native 38 kDa protein of M. tuberculosis in sera from minimally affected tuberculosis patients.

• Parasites, Hosts and Diseases
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• v.34 no.1
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• pp.35-48
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• 1996

Non-biting midges fchironomidae, Dipteral are one of the largest insect families, which are distributed worldwidely and are found in nearly all types of inland waters. They are known to be aggressive inhalant allergens which cause allergenic diseases. In this study, the crude antigens of Chironomus SavipLumn adults which are most widely distributed in Korea were extracted. and their allergens were analysed with the sera from experimentally sensitized mice. The mice were immunized with $1{\;}\mu\textrm{g}{\;}or{\;}10{\;}\mu\textrm{g}$ of the crude antigens, respectively, and the specific serum IgE levels were measured by both ELISA and passive cutaneous anaphylaxis (PCA) techniques. The highest levels of both total IgE and chironomid-specific IgE were found in the mouse sera obtained after 9 weeks of the first infection with $1{\;}\mu\textrm{g}$ crude antigen. The crude antigen was separated into 16-18 protein bands on gel by SDS-PAGE. The crude extract was assessed by SDS-PAGE/immunoblot analysis. One IgE-binding band (65 kDa) was detected by developing with colorimetric substrate, and 4 IgE-binding bands (65, 52, 35 and 25 kDa) by developing with CSPD chemiluminescent substrate. The SDS-PAGE gel of the crude extract of chironomid adults was equally cut into 30 pieces and each of them was eluted to isolate proteins by molecular weight, and the allergenicity of each eluate was assessed by applying P-K test on rats. Proteins of 65, 35 and 15 KDa showed the highest P-K titer (${\times}512$) which was 16 times higher than that of the crude extract (${\times32}$). The P-K titer of 52 kDa protein was also 4 times higher ($128{\times}$) than that of the crude extract, whereas the 25 kDa protein poorly responded, which seemed not antigenic. In conclusion, the present result in mice demonstrated that adults of Chironomus fcuiplumus, a predominent species in Korea, cause allergenic diseases and the main allergens are 65, 52, 35 and 15 kDa proteins, of which 65 kDa protein seems to be a main allergen.

• Parasites, Hosts and Diseases
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• v.26 no.4
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• pp.239-244
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• 1988

In order to observe the antigenic fractions in saline extract of adult Paragonimus westermani, proteins in the crude extract were separated by sodium dodecyl sulfate-polyacylamide gel electrophoresis(SDS.PAGE) in reducing conditions. The separated protein fractions were transferred to nitrocellulose paper on which 20 sera from human paragonimiasis were reacted and immunoblottrd. Out of 15 stained protein bands in SDS-PAGE, 7 reacted with infected sera while 8 did not. Additionally, 7 unstained protein bands in SDS-PAGE reacted with the sera. Of 14 reacted bands, 30 kilodalton(kDa) band was the most frequently reacted (95%) and was a strong antigen. Protein bands of 23 and 46 kDa were also strong antigens. Bands of over 150 kDa, 120 kDa, 92 kDa, 86 kDa, 74 kDa, 62 kDa, 51 kDa, 32 kDa, 28 kDa, 16.5 kDa and 15.5 kDa were also reactive but their frequencies of the reaction were variable. Key words: Paragonimus westermani, human paragonimiasis, antigenic proteins, SDS-PAGE/ immunoblot

• Parasites, Hosts and Diseases
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• v.36 no.4
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• pp.269-275
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• 1998

Anti-Neospora caninum antibody was detected in anti-Toxoplasma gondii positive and negative human sera by ELISA, western blot and immunofluorescence assay (IFA). Twelve cases out of 172 (6.7％) Toxoplasma-positive sera cross-reacted with both T. gondii and N. caninum antigens, and one out of 110 Toxoplasma-negative sera reacted with N. caninum antigen by ELISA. By western blot, all 12 sera reacted with T. gondii antigens with various banding patterns but specifically at 30 kDa (SAG 1), and 22 kDa （SAG2) bands. With N. caninum antigen, the number of reactive bands was reduced, however a 43 kDa band reacted in three cases in Toxoplasma-positive sera in addition to one in Toxoplasma-negative control sera. All sera of the Toxoplasma-positive group labeled surface membrane of T. gondii, but reacted differently with N. caninum. Fluorescence was detected in surface membrane, subcellular organelles, or both in N. caninum. And one case in the Toxoplasma-negative group also reacted with N. caninum strongly in subcellular organelles. This suggested that the antibody against N. caninum may be present in human sera although the positive rate was very low in this study. The possibility of human infection with N. caninum remains to be evaluated further.

• Korean Journal of Veterinary Research
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• v.39 no.1
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• pp.159-168
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• 1999

Swine whipworm(Trichuris suis) is cosmopolitan nematode which can cause serious pathology in immature stage(larva2~larva5) of infected pigs, such as anorexia, diarrhea, anemia, and death in heavy infections. In this larval stages, it is very difficult to diagnose the infection of whipworm and to differentiate from other common swine gastrointestinal disorders such as 21 day scours which are associated with TGE virus, rota virus, coccidium, and the stress of weaning. In this experiment, the isolated antigens of Trichuris spp. were carried out to examine the structure and specificity of antigens and to select the reasonable antigens which would be used in serological diagnosis by electrophoresis, Western blotting, ELISA. The results of this experiment were as follows; 1. The common fractions of each Trichuris suis antigen were identified 28,32,45, 80kDa by SDS-PAGE with silver stain and four major fractions could be detected in positive swine sera by Western blot analysis. 2. The OD(optical density) values of somatic and excretory-secretory antigens which were reacted against positive(negative) sera from pigs infected with Trichuris suis by ELISA reader were; 1) OD values($mean{\pm}SD$) of adult somatic antigen against positive(negative) sera were $0.30{\pm}0.12(0.09{\pm}0.006)$ and third-stage larva of somatic antigen were $0.28{\pm}0.038(0.10{\pm}0.005)$. And OD values of excretory-secretory antigens of adult and third-stage larva were $0.24{\pm}0.031(0.11{\pm}0.005)$ and $0.08{\pm}0.013(0.10{\pm}0.003)$, respectively. 2) OD values of adult somatic, larval somatic antigen and adult excretory-secretory antigen response to positive sera were significantly (p<0.01) associated with negative swine sera. And the Cut-off OD values(minimum positive value) were determined to be mean negative value plus 3 SD that would minimized the risk of false positives. 3. The OD values of somatic antigens of T suis and T vulpis against swine positive(negative) sera were $0.30{\pm}0.120(0.09{\pm}0.006)$ and $0.25{\pm}0.141(0.09{\pm}0.003)$. These data mean that the somatic antigens of T suis and T vulpis were able to diagnose T vulpis infection in dogs as well as T suis infection in pigs. These results suggest that somatic antigen of third-stage larva and excretory-secretory antigen of adult T suis could be used the diagnostic antigen by serological test(ELISA) in immature Trichuris spp. infection.

• Parasites, Hosts and Diseases
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• v.25 no.2
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• pp.159-167
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• 1987

To analyse the antigen specificity of patients sera from 24 confirmed neurocysticercosis and a monoclonal antibody, SDS-PAGE using 10~15% linear gradient gel and EITB were done. Cystic fluid, saline extracts of scolex and of whole worm of C. cellulosae, saline extracts of sparganum, hydatid cyst fluid, saline extracts of Fasciola, Clonorchis and Paragonimus were used as antigen. Of protein bands in cystic fluid of C. cellulosae, patient sera reacted frequently to bands of 152, 94, 64, 48, 24, 15, 10 and 7kDa proteins. To saline extracts of scolex and whole worm of C. cellulosae, patients sera reacted frequently to 94, 64, 52, 39, 34, 15 and 10kDa bands. Two bands in sparganum extract (130 and 64kDa) and two bands in hydatid cyst fluid (52 and 27kDa) were cross-reacting bands with sera from cysticercosis patients. Saline extracts of Fasciola, ClonorchiJ and Paragonimus did 'not exhibit cross-reacting bands. Monoclonal antibody to cystic fluid of C. cellulosae was found to react with low molecular weight proteins of 15, 10 and 7kDa.

• Journal of Animal Science and Technology
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• v.44 no.5
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• pp.633-642
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• 2002

Enteric colibacillosis has economically become an important disease of young animals as a result of increasing intensification of farrowing management. The objective of this experiment is to isolate fimbrial antigen from enterotoxigenic E. coli F41, to develop specific polyclonal IgY which can effectively neutralize or reduce the proliferation of pathogens in feed or living animal system, and to apply IgY technologies to animal industry. The results obtained were as follows: The molecular weight of the purified F41 antigen was 29,500 dalton on sodium dodecyl sulfate-polyacrylamide gels. Fimbrial antigen was confirmed by the western blot method. It was observed that after immunization the level of serum antibody titer of laying hen was shown in two weeks and gradually increased. The antibody titer in egg yolk appeared two weeks after it was shown in serum antibody. The titers of egg yolk antibody were gradually increased to the maximum level of 320,000 (antigen 50${\mu}g$/$m\ell$), 450,000 (antigen 200${\mu}g$/$m\ell$), and 320,000 (antigen 600${\mu}g$/$m\ell$). According to the results of specificity test by ELISA, the anti-F41 antibodies from chicken serum and egg yolk reacted only with ETEC F41 antigen. There was no cross reaction with other ETEC strains (K88, K99, and 987P). In vitro condition, as a result of antigen binding ability of yolk antibodies, bacterial concentration was rapidly decreased to $10^5$ CFU/$m\ell$ from $10^9$ CFU/$m\ell$ when 2${\sim}$4 mg/$m\ell$ of freeze dried WSF (water soluble fraction) was added.

• Parasites, Hosts and Diseases
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• v.51 no.4
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• pp.433-440
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• 2013

Toxocariasis is a worldwide zoonosis caused by larvae of ascarid nematodes of dogs or cats, Toxocara canis or T. cati. Diagnosis of human toxocariasis currently relies on serology that uses T. canis excretory-secretory antigen to detect specific IgG antibodies by ELISA. We investigated the serodiagnostic efficacy of ELISA using crude antigen of T. canis larvae (TCLA). Serum specimens of 64 clinically confirmed toxocariasis, 115 healthy controls, and 119 other tissue-invading helminthiases were screened by ELISA using TCLA. The ELISA using TCLA showed 92.2% (59/64 patient samples) sensitivity and 86.6% (103/119) specificity. Its positive diagnostic predictivity was 78.7% and negative predictivity was 97.8%. No serum of healthy controls reacted but that of anisakiasis (45.5%), gnathostomiasis (19.2%), clonorchiasis (15.8%), sparganosis (11.1%), and cysticercosis (6.3%) cross-reacted. Immunoblot analysis on TCLA recognized antigenic proteins of 28- and 30-kDa bands in their dominant protein quantity and strong blotting reactivity. The present results indicate that the ELISA using our TCLA antigen is acceptable by the sensitivity and specificity for serodiagnosis of human toxocariasis. ELISA with TCLA is recommended to make differential diagnosis for patients with any sign of organ infiltration and eosinophilia.