1986 Fiscal Year Final Research Report Summary
Functional differenciation and structure in sea-squirt antigens
| Project/Area Number |
60560096
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
応用生物化学・栄養化学
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
SHIGETA Seiko Faculty of Engineering, Hiroshima Univ., Assist.Prof., 工学部, 助手 (10034381)
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| Co-Investigator(Kenkyū-buntansha) |
ONO Kazuhisa Faculty of Engineering, Hiroshima Univ. Assist.Prof., 工学部, 助手 (10144883)
OKA Satoru Faculty of Engineering, Hiroshima Univ. Prof., 工学部, 教授 (80034320)
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| Project Period (FY) |
1985 – 1986
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| Keywords | antigen / asthna / allergen / sea-squirt / chemical structure / epitope / carbohydrate / N-acetylgalactosanine |
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| Research Abstract |
Three acidic glycoprotein preparation termed Gi-rep, Ei-M and DIIIa are the antigens specific to sea-squirt allergy. However, DIIIa is apparently discriminated from the other two by its activity to induce asthmatic attack and conjunctival congestion, though it gives a remarkable erythema in skin tests against allergic patients of sea-squirt allergy, similarly Gi-rep and Ei-M, Thus, DIIIa was examined for its mucosal allergenicity in relation to the chemical properties.
Periodate oxidation eliminated not only the mucosal reactivity but also the skin reactivity from DIIIa. Thus, it was suggested that both activities depend upon a certain epitope residing in the carbohydrate chains of the antigen. On the other hand, the treatment with Pronase E eliminated the mucosal reactivity from DIIIa but the skin reactivity was still conserved. This suggested that the mucosal reactivity of DIIIa required not only the carbohydrate epitope but also some proteinic structure which probably contributed to its mucosa permeability.
Then, by the <beta> -elimination reaction, an O-glycosidically linked carbohydrate chain was isolated from DIIIa. By structural analysis. it was recognized that the active saccharide contained two mol/mol of non-resucing terminal N-acetylgalactosamine (t-GalNAc) residues.
Furthermore, a heterogeneous but bulky fraction of glycoprotein termed H antigen from sea-squirt was subjected to the <beta> -elimination to obtain a relatively large amount of the allergenically active oligosaccharides. In 23 isolated saccharides, 12 of allergenically active saccharides were recognized to be branched saccharides having more than 2 mol/mol t-GalNAc. These observations suggest that the epitopes of sea-squirt antigens including H antigen have a common structure that contains t-GalNAc in common.
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