1988 Fiscal Year Final Research Report Summary
Design of Adsorbents for Immunoaffinity Chromatography by Modification of Antibody
| Project/Area Number |
62470108
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
化学工学
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| Research Institution | Kyoto University |
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Principal Investigator |
SADA Eizo Faculty of Engineering, Kyoto University ,Professor, 工学部, 教授 (60023024)
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| Co-Investigator(Kenkyū-buntansha) |
TERASHIMA Masaaki Faculty of Engineering, Kyoto University ,Instructor, 工学部, 助手 (30172092)
KATOH Shigeo Faculty of Engineering, Kyoto University ,Lecturer, 工学部, 講師 (20026272)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Immunoaffinity Chromatography / Antibody / Modification of Molecule / Cleavage of Antibody / Antigen Binding Ratio / プロテアーゼ分解抵抗性 |
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| Research Abstract |
Immunoaffinity chromatography, which depends on the highly selective and specific interaction between antigen and antibody, is an excellent method to purify bioproducts to high degrees. In the present work, antibody ligands were chemically modified or cleaved in order to improve the resistance to proteolytic digestion or to suppress undesirable physiological effects of immunoadsorbents.
Antibodies were modified with polyethylene glycol activated with cyanuric chloride, and immunoadsorbents were prepared with use of modified antibodies as ligands. These immunoadsorbents showed the high resistance to proteolytic digestion by trypsin and pepsin, which have specificity for hydrolysis site of peptide bond. In the case of pronase, which has no specificity, they also showed higher resistance than unmodified immunoadsorbents. On modification without protection of antigen binding site of antibody, the binding ratio of antigen decreased with increase in the degree of modification, while protection of the site with antigen improved the binding ratio. Since the resistance to proteolytic digestion of immunoadsorbents is improved by PEG modification, the modified absorbents will show long lices even in immunoaffinity chromatography with crude material containing proteases.
In extracorporeal circulation to remove immunocomplexes by immunoadsorbents, antibody ligands might cause undesirable physiological effects, such as activation of compliment. Since an antibody molecule can be cleaved by papain into F_<ab> fraction, which has antigen binding site, and F_c region, which shows physiological activities of antibody, these undesirable effects can be avoided by using F_<ab> fragment as ligand. The adsorption equilibrium of F_<ab> was similar to that of igg. The effects of pH and ionic strength were also the same in both F_<ab> and IgG. therefore, F_<ab> fragment is useful as ligand in order to avoid undersirable physiological effects caused by F_c region.
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