• Tuberculosis and Respiratory Diseases
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• v.61 no.3
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• pp.239-247
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• 2006

Background: Culture filtrate proteins secreted by mycobacteria are thought to play an important role in inducing protective immunity and to develop new methods for diagnosing tuberculosis. Methods: A culture filtrate protein of M. avium that was strongly reactive with goat antiserum against M. intracellulare was constructed. Its homologous protein (TB-14) in M. tuberculosis was cloned, expressed and purified. The inductions of IFN-${\gamma}$ stimulated with $10{\mu}g$ of TB-14 recombinant protein and $10{\mu}g$ PPD were estimated by using whole bloods from seven PPD (-) subjects, seven PPD (+) healthy volunteers and nine tuberculosis patients. Results: M. avium culture filtrate protein was confirmed as a hypothetical protein that was termed contig 116. A novel 14-kDa recombinant protein (TB-14) of M. tuberculosis was composed of 148 amino acids, including 30 amino acids of the signal peptide, and it showed 78% homology with M. avium. In the PPD (+) healthy volunteers, recombinant TB-14 protein strongly induced the secretion of IFN-${\gamma}$ in whole blood cultures. Conclusion: These results suggest that TB-14 recombinant protein might play an important role in inducing cell-mediated immunity against tuberculosis. Furthermore, TB-14 protein antigen and its antiserum will be available for the development of new diagnostic tools for tuberculosis.

• Journal of Life Science
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• v.18 no.2
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• pp.241-248
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• 2008

This study has been carried out to secretion antibodies for the purpose of preventing the infection of Helicobacter pylori and using them as a supplement for treatment. This experiments have been separated antigens from H. pylori and observed into antibody production and the agglutination of H. pylori for the separated antigens. As major antigenic proteins separated from H. pylori, the following could be verified: 12 kinds of band for whole cell (WC), seven kinds of band for outer membrane protein (OMP), three kinds of band for crude urease, and one kind of band for lipopolysaccharide (LPS). The IgG anti-H. pylori antibody of separated antigens showed $77.9{\pm}6.4{\mu}g/ml$ for we (L), $84.9{\pm}6.4{\mu}g/ml$ for OMP, and $123.8{\pm}2.9{\mu}g/ml$ for crude urease, at the same antigen concentration of $20{\mu}g/100ull$, which showed the most at the crude urease. And it turned out that the IgA antibodies were generated with $2.5{\pm}0.32{\mu}g/ml$ for WC (L), $2.0{\pm}0.43{\mu}g/ml$ for OMP, and $1.3{\pm}0.25{\mu}g/ml$ for crude urease, which demonstrated the most for WC (L) antigens. As a result of verifying the immunogenecity of antigenic protein through the Western blotting, major antigenic substances could be confirmed as follows: 10 kinds for WC, six kinds for OMP and three kinds for crude urease. The agglutination values on the H. pylori of the antibody were $2^5,\;2^5,\;2^6\;and\;2^7$ at the antigen serums of anti-WC (H), anti-WC (L), anti-OMP and anti-crude urease, respectively, which indicated the highest for the antigen serum of anti-crude urease. The urease activation-inhibiting absorbance of antigen serum created by each antigen was $0.14{\pm}0.01$ for WC (H), $0.16{\pm}0.01$ for WC (L), $0.18{\pm}0.03$ for OMP, and $0.18{\pm}0.04$ for urease, demonstrating a significant inhibiting effect, compared with $0.26{\pm}0.02$ of the control group.

• Journal of Life Science
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• v.28 no.12
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• pp.1416-1423
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• 2018

With strong biotin binding affinity ($K_D=10^{-14}M$), the tetrameric feature of streptavidin could be used to increase the antigen binding activity of a camel heavy chain (VHH) antibody through their fusion, here stained with biotinylated horseradish peroxidase and subsequent immunoassays ELISA and Western blot analysis. For this application, we cloned the streptavidin gene amplified from the Streptomyces avidinii chromosome by PCR, and this was fused to the gene of the 8B9 VHH antibody which is specific to green fluorescent protein (GFP) antigens. To express a soluble fusion protein in Escherichia coli, we used the pUC119 plasmid-based expression system which uses the lacZ promoter for induction by IPTG, the pelB leader sequence at the N-terminus for secretion into the periplasmic space, and six polyhistidine tags at the C-terminus for purification of the expressed proteins using an $Ni^+$-NTA-agarose column. Although streptavidin is toxic to E. coli because of its strong biotin binding property, this soluble fusion protein was expressed successfully. In SDS-PAGE, the size of the purified fusion protein was 122.4 kDa in its native condition and 30.6 kDa once denatured by boiling, suggesting the tetramerization of the monomeric subunit by non-covalent association through the streptavidin moiety fusing to the 8B9 VHH antibody. In addition, this fusion protein showed biotin binding activity similar to streptavidin as well as GFP antigen binding activity through both ELISA and Western blot analysis. In conclusion, the protein resulting from the fusion of an 8B9 VHH antibody with streptavidin was successfully expressed and purified as a soluble tetramer in E. coli; it showed both biotin and GFP antigen binding activity suggesting the possible production of a tetrameric and bifunctional VHH antibody.