- Affinity Maturation of an Anti-Hepatitis B Virus PreS1 Humanized Antibody by Phage Display
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Gi-Hyeok Yang , Sun Ok Yoon , Myung Hee Jang , Hyo Jeong Hong
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J. Microbiol. 2007;45(6):528-533.
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DOI: https://doi.org/2640 [pii]
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 Abstract
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In a previous study we generated an anti-Hepatitis B Virus (HBV) preS1 humanized antibody (HzKR127) that showed in vivo HBV-neutralizing activity in chimpanzees. However, the antigen-binding affinity of the humanized antibody may not be sufficient for clinical use and thus affinity maturation is required for better therapeutic efficacy. In this study, phage display technique was employed to increase the affinity of HzKR127. All six amino acid residues (Glu95-Tyr96-Asp97-Glu98-Ala99-Tyr100) in the heavy (H) chain complementarydetermining region 3 (HCDR3) of HzKR127 were randomized and phage-displayed single chain Fv (scFv) library was constructed. After three rounds of panning, 12 different clones exhibiting higher antigen-binding activity than the wild type ScFv were selected and their antigen-binding specificity for the preS1 confirmed. Subsequently, five ScFv clones were converted to whole IgG and subjected to affinity determination. The results showed that two clones (B3 and A19) exhibited an approximately 6 fold higher affinities than that of HzKR127. The affinity-matured humanized antibodies may be useful in anti-HBV immunotherapy.
- Stimulation of Tissue Transglutaminase Activity by Clostridium botulinum Neurotoxin Type B
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Yu Seok Moon , Gi-Hyeok Yang , Sang-Dal Rhee , Hyun Ho Jung
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J. Microbiol. 2003;41(2):161-164.
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Abstract
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Recombinant light chain of Clostridium botulinum neurotoxin type B stimulated transglutaminase activity in a dose dependent manner. Compared to native toxin, recombinant light chain showed a greater stimulatory effect on transglutaminase activity. Zn-chelating agents, inhibiting the roteolytic activity of the clostridial toxins, did not interfere with this stimulation. These results suggest that the light chain plays a major stimulatory role, which is not due to its metallopeptidase activity, but is possibly due to specific interaction with transglutaminase. More importantly, this report provides a new insight into the intracellular action of C. botulinum neurotoxins.
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