• Journal of Yeungnam Medical Science
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• v.8 no.1
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• pp.53-62
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• 1991

Experiments were performed in mice(Balb/C) to support the basic efficacy of the human immunoglobulin (IgG) preparation. The antibacterial activity of IgG purified from human sera was examined with or without the quinolone agent, ciprofloxacin(CPFX), against Pseudomonas aeruginosa isolated from clinical specimens. Results were as follows: Antibacterial activities in terms of the percentage of survivors, after administration of Ps. aeruginosa into mouse intraperitoneal cavity were in the following order, single IgG group, CPFX administration after IgG pretreatment group, IgG and CPFX combined administration group and CPFX alone group. The number of living bacteria was monitored in blood and liver tissue of mice infected with Ps. aeriginosa and treated by IgG administration. The increase of living bacteria in liver was more drastic than that in blood. Leukocytosis was observed in mice injected with IgG, excluding those only with ciprofloxacin, after 8 hours of administration to see a decrease to normal number of bacteria after 18 hours. No significant difference was noticed between pretreatment group and post treatment group. In vitro susceptibility test of IgG against Ps. aeruginosa, minimal inhibitory concentration(MIC) was $250{\mu}g/ml$, resistant to IgG, regardless of a combined administration with CPFX. In vitro test revealed that the IgG itself did not have anti-Ps. aeruginosa activity.

• Parasites, Hosts and Diseases
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• v.47 no.2
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• pp.171-174
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• 2009

The antigen location of Cryptosporidium parvum, which stimulates antibody formation in humans and animals, was investigated using infected human sera. Immuno-electron microscopy revealed that antigenicity-inducing humoral immunity was located at various developmental stages of parasites, including asexual, sexual stages, and oocysts. The amount of antigen-stimulating IgG antibodies was particularly high on the oocyst wall. The sporozoite surface was shown to give stimulation on IgG and IgM antibody formation. Trophozoites implicated the lowest antigenicity to humoral immunity, both IgG and IgM, by showing the least amount of gold labeling. Immunogold labeling also provided clues that antigens were presented to the host-cell cytoplasm via feeder organelles and host-parasite junctions.

• The Korean Journal of Nuclear Medicine
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• v.25 no.2
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• pp.259-265
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• 1991

The purpose of this study is to investigate the ability of I-131 labeled polyclonal human immunoglobulin to localize an infection. In our country, indium-111 labeled leukocyte or Tc-99m labeled IgG are not readily available because of compex, time-consuming procedure and cost. So we tried to localize infection with I-131 labeled IgG which could be easily prepared. Six rats, infected with staphylococcus aureus in a thigh muscle, received I-131 labeled IgG intravenously and I-131 labeled bovine serum albumin (BSA) were injected to other 5 infected rats. Scintigrams were made at 1, 4, 24, 48, 72 hour later. The radiopharmaceutical demonstrated significant accumulation at the site of infection. The accumulation of I-131 labeled IgG at the site of infection was significantly (P<0.05) higher than that of I-131 labeled BSA at 48, 72 hour. Similar finding could be found at 24 hour imaging, but it was not significant statistically. Therefore it was found that vascular permeability alone could not account for the mode of action of I-131 labeled IgG and it was considered that specific binding played a role. In conclusion, focal sites of inflammation can be detected with I-131 labeled nonspecific human polyclonal IgG and it seems that this method can also be applied to localization of human infection.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.11a
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• pp.143-145
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• 1994

Chimeric fusion proteins involving IgG have proven valuable in studying protein-protein interactions and may possess therapeutic applications as well. For example, three receptor subtypes for the natriuretic peptides, when fused to the Fc portion of human IgG ${\gamma}$ chain, were quantitatively and qualitatively indistinguishable from the native receptor, thus allowing detailed structure-function studies of the receptor. In an attempt to block human immunodeficiency virus infectivity with soluble derivatives of CD4, a CD4/IgG Fc chimeric molecule was shown to increase the plasma half life of soluble CD4 and possessed the added advantage of IgG Fc-mediated placental transfer. In the case of the KGFR, this approach provided a framework for dissection of its ligand binding domains and made it possible to demonstrate that high affinity binding sites for two ligands, aFGF and KGF, reside within different receptor Ig-like domains. Chimeric molecules fused to immunoglobulins would have the advantages of secretion from transfected cells as well as detection and purification from medium utilizing Staphylococcus aureus Protein A. In addition, where highly related receptors make their discrimination very hard due to the difficulties in generating specific immunochemical probes, IgG fusion protein with tailor-made specificities confers particular advantages to elucidate patterns of receptor distribution and expression. The approach described here may have general applications in defining ligand-receptor interactions as well as searching for specific agonists and antagonists of receptor function.

• Journal of Microbiology
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• v.42 no.3
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• pp.211-215
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• 2004

Toxoplasmosis has been well known as an important human infection to consider especially in pregnant women. Although many serologic methods are available, the diagnosis of toxoplasmosis can be extremely difficult. The presence of increased levels of Toxoplasma-specific IgG antibodies indicates an infection, but it does not differentiate between a recent and past infection. The purpose of our study was to compare the performance of the ELISA T. gondii IgG/IgM test, a widely used enzyme-linked immunosorbent assay, to the ELISA IgG avidity method. One hundred and four serum samples (from 38 males and 66 females) were tested and evaluated from symptomatic patients (chorioretinitis, lymphadenopathy), and from women in their first trimester of pregnancy who were suspected of having toxoplasmosis, The high IgG avidity and ELISA IgG antibody levels were in agreement for 51 of the specimens (49.0％). Thirty-eight discrepant (borderline) results from the IgG avidity method were positive for IgM (3 specimens) and IgG (37 specimens). Interestingly, out of the eight serum samples that were positive for both IgG and IgM antibodies, two samples were low IgG avidity, and three samples were borderline. There was no statistically significant relation observed between the results of the IgG avidity method and the ELISA IgG test, and the IgG avidity method and ELISA IgM test (X$^2$=1.987; p=0.370 and X$^2$=2.152; p=0.341, respectively). The IgG avidity method was considered easy to perform and an acceptable approach for the differentiation of discrepant results (recent/chronic) and for the current detection of T. gondii antibodies. We concluded that the determination of IgG avidity is a helpful tool for the diagnosis of the ocular form of toxoplasmosis and it is a safe method for screening this disease in the first trimester of pregnancy.

• 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.

• Parasites, Hosts and Diseases
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• v.35 no.1
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• pp.39-46
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• 1997

The present study was undertaken to determine whether live T. uaginnlis degrades human secretory IgA, serum If and IgG molecules. Human immunoglobulins were exposed to live trophozoites, parasite Iysate, and excretory-secretory product (ESP) of T ucginnlis. To determine the fragmentation of immunoglobulins, the reaction sample was subjected to SDS-PAGE and EITB, and peroxidase conjugated antihuman IgA and IgG were used as probes. Live trophozoites degraded secretory IgA, serum IgA and IgG, and degradation were pressed forward by the prolongation of the incubation time and by increasing the number of trichomonads respectively. Also the Iysates and ESP of trichomonads degraded IgA and IgG. The cysteine and serine proteinase inhibitors such as I-64, antipain, iodoacetic acid, iodoacetamide, TLCK reduced the ability of cleaving immunoglobulins. The proteinase activity and cytotoxicity of T. uaginnlis to HeLa cells were decreased when live T. vusinalis was treated with metallo-proteinase inhibitor as well as cysteine and serine proteinase inhibitors. These results suggest that proteinase secreted from live T ucginclis may play a part role in host pathogenesis by T. uosinnlis, and the cleaving ability of host immunoglobulins by the proteinase may contribute as a one of immune evasion mechanism for parasite survival in the host.

• The Korean Journal of Nuclear Medicine
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• v.33 no.1
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• pp.84-93
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• 1999

Purpose: We investigated the direct labeling method of antibody with $^{99m}Tc$ and $^{188}Re$ and examined the stability and function of these labeled compounds in in vitro and in vivo. Materials and Methods: Disulfide bond of nonspecific human IgG was reduced to -SH group by 2-mercaptoethanol. Stannous ion was used to reduce $^{99m}Tc$ and $^{188}Re$. The stability of $^{99m}Tc$-IgG and $^{188}Re$-IgG was estimated upto 24 hrs. Biodistribution was evaluated in abscess bearing rats at 4 and 24 hr post-injection of $^{99m}Tc$ or $^{188}Re$ labeled IgG. Results: The number of -SH group per reduced IgG molecule was 2.34. The labeling yield of $^{99m}Tc$-IgG and $^{188}Re$-IgG were 90% and 95%, respectively The stability of $^{99m}Tc$-IgG at 1, 4, 6 and 24 hr was 91%, 83%, 78%, 7% and that of $^{188}Re$-IgG at 1, 4, 16 and 24 hr was 94%, 80%, 47%, 42%, respectively. At 4 hr post-injection of $^{99m}Tc$-IgG, high uptake was found on kidney, blood, stomach and abscess ($9.42{\pm}0.68,\;1.43{\pm}0.24,\;0.86{\pm}0.18,\;0.72{\pm}0.10$ %ID/g, respectively). The uptakes at 24 hr were kidney, abscess,.itomach, and blood in descending order. In case of $^{188}Re$-lgG, high uptake at 4 hr post injection appeared on kidney, blood, abscess and stomach ($3.92{\pm}0.62,\;1.32{\pm}0.08,\;0.88{\pm}0.01,\;0.26{\pm}0.06$, respectively). The uptakes at 24 hr were kidney, abscess, blood and stomach in descending order. The abscess to blood uptake ratio of $^{99m}Tc$-IgG was 0.5 at 4 hr and 2.02 at 24 hr and that of $^{188}Re$-IgG was 0.67 and 1.29. Conclusion: $^{99m}Tc$-IgG and $^{188}Re$-IgG canbe labeled efficiently with direct labeling method. However, $^{99m}Tc$-IgG and $^{188}Re$-IgG, labeled with direct method, was unstable. Further study is needed to enhance the stability of the antibody labeling.

• BMB Reports
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• v.48 no.1
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• pp.36-41
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• 2015

Recently, we demonstrated that human serum amyloid P component (SAP) specifically recognizes exposed bacterial peptidoglycan (PGN) of wall teichoic acid (WTA)-deficient Staphylococcus aureus ${\Delta}$tagO mutant cells and then induces complement-independent phagocytosis. In our preliminary experiments, we found the existence of human serum immunoglobulins that recognize S. aureus PGN (anti-PGNIgGs), which may be involved in complement-dependent opsonophagocytosis against infected S. aureus cells. We assumed that purified serum anti-PGN-IgGs and S. aureus ${\Delta}$tagO mutant cells are good tools to study the molecular mechanism of anti-PGN-IgG-mediated phagocytosis. Therefore, we tried to identify the intracellular molecule(s) that is involved in the anti-PGN-IgG-mediated phagocytosis using purified human serum anti-PGN-IgGs and different S. aureus mutant cells. Here, we show that anti-PGN-IgG-mediated phagocytosis in phorbol myristate acetate-treated U937 cells is mediated by $Ca^{2+}$ release from intracellular $Ca^{2+}$ stores and anti-PGN-IgGdependent $Ca^{2+}$ mobilization is controlled via a phospholipase C${\gamma}$-2-mediated pathway.

• Biomedical Science Letters
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• v.3 no.2
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• pp.131-138
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• 1997

IgG-$^{188}$Re conjugate was prepared for the diagnosis of abscess. The IgG molecules reduced by 2-mercaptoethanol contained 1.5 free sulfhydryl groups per IgG molecule. The reduced IgG molecule was labelled with $^{188}$Re through chelate to 99％ of labelling yield. The radiochemical purity of IgG-$^{188}$Re conjugate was maintained at 90％ in the presence of human serum for 1 hour. The IgG-$^{188}$Re was intravenously administered into staphylococcal abscess-bearing rats and their biodistribution was monitored at 4 and 24 hours post injection. The IgG-$^{188}$Re conjugate was moderately localized in the abscess tissue. This result implies that the IgG-$^{188}$Re conjugate can be a tool for abscess diagnosis. This technique can be applied for the preparation of various monoclonal antibody labelled with $^{188}$Re.