• Parasites, Hosts and Diseases
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• v.37 no.4
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• pp.243-248
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• 1999

The present study analyzed serum IgG subclass antibody reaction to major antigenic bands of Clonorchis sinensis to investigate improvement of its serodiagnosis. Of the four subclass antibodies, IgG1 and IgG2 antibodies were produced but not specific, IgG3 antibody was least produced, and IgG4 antibody was prominent and specific. The serum IgG antibody reaction to any of 43-50, 34-37, 26-28, and 8 kDa bands was found in 65.5％ of 168 egg positive cases while IgG4 antibody reaction was found in 22.0％ of them. The positive rates of IgG and IgG4 antibodies were directly correlated with the intensity of infection. All of the sera from heavily infected cases over EPG 5,000 showed positive reaction for specific IgG and IgG4 antibodies. The specific serum IgG4 antibody disappeared within 6 months after treatment. The bands of 35 kDa and 67 kDa cross-reacted with IgG antibodies but not with IgG4 antibodies in sera of other trematode infections. The present findings suggest that serum IgG4 antibody reaction to 8 kDa band is specific but not sensitive. Any method to increase its sensitivity is required for improved serodiagnosis.

• Journal of Sensor Science and Technology
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• v.7 no.4
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• pp.263-270
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• 1998

Surface Plasmon Resonance (SPR) sensor system, has rapid response and high sensitivity, can be applicable for detecting reaction times of many biospecific interactions. A SPR sensor system was constructed to detect the antigen-antibody reactions of salmonella and hIgG (human immunoglobulin G). Sensor chips made of gold thin film were used for detecting biological bindings of antigen and antibody reactions. The antigen and antibody reactions for salmonella and hIgG were carried out with various time intervals to observed characteristics of these reactions using SPR sensor system. The resonance angle shift changes were clearly observed at the time of salmonella or hIgG antibody injection into sample cell since each antibody was self-assembled on gold chip surface of the sensor. It was found that the antibodies of salmonella and hIgG reacted with its sensor chip surface in 10 minutes and 60 minutes respectively. And the antigens of both salmonella and hIgG were bound to its antibody within 1 minute.

• YAKHAK HOEJI
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• v.31 no.2
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• pp.64-69
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• 1987

Monoclonal antibodies against human chorionic gonadotropin (hCG) were prepared and characterized by examining isotype, epitope binding, cross reactivity and affinity constants. And a sandwich type enzyme immunoassay for native hCG was developed with solid phase monoclonal antibody against the conformational determinant expressed only on native hCG and horseradish peroxidase conjugated monoclonal antibody against the $\beta$-subunit of hCG. The assay was sensitive to 1 mIU hCG/ml and shown a linear response up to 200 mIU hCG/ml. The cross reactivity for luteinizing hormone and $\beta$-subunit of hCG were 1% and 0.18%, respectively.

• BMB Reports
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• v.34 no.1
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• pp.47-50
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• 2001

A one-step, two-site enzyme immunoassay was developed for measuring human alpha-fetoprotein (AFP) in serum and amniotic fluid using monoclonal antibodies (McAb) by eliminating the high-dose hook effect. Three McAbs that recognize different epitopes were selected among 16 different clones on the basis of epitope mapping, two for immobilization and one for horseradish peroxidase conjugation. This one-step immunoassay system is more convenient and rapid compared to a conventional two-step sandwich immunoassay system. It did not exhibit the hook effect to around 2.7 mg/ml of AFP, which is probably one of the highest concentrations of AFP in the serum. The dose-response curve of the system was linear to 500 mg/ml of AFP and the system could differentiate as low as 1 mg/ml of AFP The intra- and inter-assay variations were in an acceptable range; 95~104% and 97~105% respectively Its correlation with other commercial systems was around 95%.

• BMB Reports
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• v.31 no.1
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• pp.106-110
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• 1998

We have employed a DNA-native-polyacrylamide gel electrophoresis (DNA-native-PAGE) assay system to characterize the enzyme activity of the endonuclease secreted by human B lymphoblastic IM9 cells. Experimental results clearly demonstrated that the endonuclease activity of IM9 cell culture medium is distinct from that of DNase I in the DNA-native-PAGE assay system. Immunoprecipitation analysis using anti-DNase I antibody showed that the secreted endonuclease is not recognized by the antibody. The secreted endonuclease was estimated using supercoiled plasmid DNA as a substrate. The pH optimum required for the catalytic activity was determined to be in the range of pH 6.6-7.4. No significant difference in the endonuclease secretion was observed by stimulation of the IM9 cells with interferon-${\gamma}$ or interleukin-$1{\beta}$.

• YAKHAK HOEJI
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• v.48 no.1
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• pp.47-54
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• 2004

ClpP is a stress-inducible protein and proteolytic subunit of the ATP-dependent Clp protease in prokaryotes and eukaryotes. Although its physiological roles in bacterial virulence were widely studied in various organsims, including Streptococcus pneumoniae, until now the immunological effect has not been investigated. Here, we have examined the cross reactivity of S. pneumoniae ClpP antibody with other organisms's cell lysate proteins. Although the protein sequence of S. pneumoniae ClpP was highly conserved among various organisms including human, the antibody rasised by S. pneumoniae ClpP was not cross-reacted with other organism's cell lysates, which were Saccharomyces cerevisiae , human lung A549 cell, Bacillus subtilis, Pseuomonas aeruginosa, E. coli, and Salmonella typhi. It was only reacted with S. pneumoniae and Lato-bacillus thermophilus. Thus we examined the immunoprotective effect of ClpP by immunizing mice with the purified ClpP. The mean survival time of mouse was significantly increased with the ClpP immunization. These results suggest that S. pneumoniae ClpP could be used as a vaccine candidate for prevention of S. pneumoniae infection.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.926-936
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• 2003

Overexpression of human Bcl-2 protein in recombinant Chinese hamster ovary (rCHO) cells producing humanized antibody (SH2-0.32) considerably suppressed sodium butyrate (NaBu)-induced apoptosis during batch culture by using commercially available serum-free medium, which extended the culture longevity. Due to the extended culture longevity provided by the anti-apoptotic effect of Bcl-2 overexpression, the final antibody concentration of 14C6-bcl-2 culture (Bcl-2 high producer, $23\;\mu\textrm{g}\;ml^{-1}$) was 2 times higher than that of the $SH2-0.32-{\Delta}bcl-2$ culture (cells transfected with bcl-2-deficient plasmid, $10.5\;\mu\textrm{g}\;ml^{-1}$) in the presence of NaBu. To determine the effect of NaBu/Bcl-2 overexpression on the molecular integrity of protein products, antibodies purified from 14C6-bcl-2 and $SH2-0.32-{\Delta}bcl-2$ cultures in the presence of NaBu were characterized by using various molecular assay systems. For comparison, antibody purified from the parental rCHO cell culture (SH2-0.32) in the absence of NaBu was also characterized. No significant changes in molecular weight of antibodies could be observed by SDS-PAGE. From GlycoSep-N column analysis, it was found that the core oligosaccharide structure ($GlcNAc_2Man_3GlcNAc_2$) was not affected by NaBu/Bcl-2 overexpression, while the microheterogeneity of N-linked oligosaccharide structure was slightly affected. Compared with the antibody produced in the absence of NaBu, the proportion of neutral oligosaccharides was increased from 10% (14C6-bcl-2) to 16% ($SH2-0.32-{\Delta}bcl-2$) in the presence of NaBu, which was accompanied by the reduced proportion of acidic oligosaccharides, especially of monosialylated and disialylated forms. The changes in microheterogeneous oligoformal structures of antibody in turn affected the mobility of antibody isoforms in isoelectric focusing (IEF), resulting in the occurrence of some more basic antibody isoforms produced in the presence of NaBu. However, the antigen-antibody binding properties were not changed by alteration of glycosylation pattern. The competitive enzyme-linked immunosorbent assay (ELISA) showed that the antibody produced by NaBu/Bcl-2 overexpression maintained its antigen-antibody binding properties with binding affinity of about $2.5{\times}10^9{\;}M^{-1}$. Taken together, no significant effects of NaBu/Bcl-2 overexpression on the molecular integrity of antibodies, produced by using serum-free medium, could be observed by the molecular assay systems.

• The Journal of Korean Society of Virology
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• v.27 no.2
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• pp.129-135
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• 1997

Serum samples from 123 males and 123 females collected by age in 1996 were analyzed for antibodies against surface antigen of Hepatitis B virus and C22-3, C200 antigens of Hepatitis C virus. Sera from the children under the age of 10 showed 30% seropositivity to the surface antigen of Hepatitis B virus, 33.3% in $10{\sim}19$ year group, 20% in $20{\sim}29$ year group, 17.6% in $30{\sim}39$ year group, 3.3% in $40{\sim}49$ year group, 5.9% in $50{\sim}59$ year group, 8,3% in $60{\sim}69$ year group, 2.9% in $70{\sim}79$ year group, but antibody could not found in $80{\sim}86$ year group. 12 out of 123 male sera were positive, 19 out of 123 female sera were positive and overall rate of positivity of antibody against surface antigen of Hepatitis B virus was 12.6%. Serum samples from peoples under the age of 30 had not antibody against C22-3, C200 antigens of Hepatitis C virus. The positivity rate was 2.9% in $30{\sim}39$ year group. 5 out of 30 sera from $40{\sim}49$ year age group were positive, and 3 positive sera showed extremely high titer (1:524,288) but the titers of two remaining sera were 1:32, 1:8,192 respectively. 5.9% was positive in $50{\sim}59$ year group, 8.3% in $60{\sim}69$ year group, 11.8% in $70{\sim}79$ year group but all negative in $80{\sim}86$ year group 6 out of 123 male sera were positive (4.9%), 9 out of 123 female sera were positive (7.3%). Overall rate of positivity of antibody against C22-3, C200 antigen of Hepatitis C virus was 6.1 %. None out of 246 sera had both antibodies against Hepatitis B virus and Hepatitis C virus.

• Biomedical Science Letters
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• v.3 no.2
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• pp.115-123
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• 1997

$\alpha$-Fetoprotein (AFP) has been a useful marker in screening and/or monitoring patients with hepatocellular carcinoma, gonadal germ cell tumor, gastric carcinoma and neural tube defects. In the present study, it was attempted to produce anti-human AFP polyclonal antibodies and to develop a competitive enzyme-linked immunosorbent assay (ELISA) for the measurement of AFP in human plasma and amniotic fluid. AFP was isolated from amniotic fluid using an isolation procedure consisting of affinity chromatography and preparative polyacrylamide gel electrophoresis. The antibody directed against AFP was raised in rabbits. Double immunodiffusion and Western blotting methods showed that the antiserum was highly specific, reacting with only AFP-containing samples. Standard curve was obtained by using purified AFP and specific antiserum. The assay sensitivity was 5ng/ml and the working range was 5~l,000ng/ml. The within-assay and between-assay coefficient of variance (CV) was 4.5% and 8.5%, respectively. These results indicate that the assay is valuable for the measurement of AFP and found to be simple, reproducible, and accurate.

• Microbiology and Biotechnology Letters
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• v.14 no.3
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• pp.219-223
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• 1986

In order to preparr the hybridoma cells which produce a monoclonal antibody to human fibroblast interferon(Hu IFN-$\beta$), spleen cells from BALB/cmice immunized with the purified Hu IFN-$\beta$ were fused with NS-O cells, a myeloma cell line. Forty hybrids with high titer among 1300 hybrids Isolated by an ELISA screening method were subcloned using the soft agarose cloning and limiting dilution methods, and 11 hybrids were selected. As a result of iso-typing the hybrids using the mouse monoclonal typing kit, two hybridomas were found to produce 1gG 2a type of monoclonal an-tibodies. The ascites fluid from nude mice inoculated intraperitoneally with the above hybridomas was removed and purified using a protein A-Sepharose CL-4B. Monoclonal antibody was proven to have only the heavy and light chains on SDS-polyacrylamide gel electrophoresis.