Shigeta S, Takao Y, Ono K, Oka S, Jyo T
Department of Fermentation Technology, Faculty of Engineering, Hiroshima University.
Arerugi. 1990 Jan;39(1):28-35.
Among three glycoproteins, DIIIa, Ei-M, and Gi-rep, isolated from sea squirt as antigens capable of eliciting skin reaction specific to sea squirt allergy, only DIIIa induces asthmatic attack and conjunctival reaction, whereas Ei-M and Gi-rep do not. Periodate oxidation eliminated not only the conjunctival allergenicity but also the skin allergenicity from DIIIa, suggesting that the conjunctival and skin allergenicity could both be ascribed to the epitope residing in the carbohydrate chains of DIIIa. On the other hand, proteolysis with Pronase E and chemical modifications of the carboxyl or amino groups by various methods eliminated the conjunctival allergenicity from DIIIa, whereas the skin allergenicity was still retained. Therefore, the expression of conjunctival reaction was expected to be supported by a relatively small structural factor residing in the protein moiety of DIIIa, which we have tentatively designated as conjunctival allergenicity-supporting factor (CASF). CASF might contribute to the permeability of the antigen into mucosa, enabling the carbohydrate epitope to interact with the allergy-specific IgE distributed in conjunctiva and bronchi . In specificity analysis of a rabbit anti-DIIIa serum, a periodate oxidation- and acid-stable but heat- and alkali-unstable epitope (type gamma) in the protein moiety of DIIIa was also characterized as a useful marker of the antigen. However, the type gamma epitope was apparently independent of CASF that was substantially stable to alkali and heat.
从海鞘中分离出的三种糖蛋白DIIIa、Ei-M和Gi-rep，作为能够引发海鞘过敏特异性皮肤反应的抗原，只有DIIIa会引发哮喘发作和结膜反应，而Ei-M和Gi-rep则不会。高碘酸盐氧化不仅消除了DIIIa的结膜致敏性，还消除了其皮肤致敏性，这表明结膜和皮肤致敏性都可归因于DIIIa糖链中的表位。另一方面，用链霉蛋白酶E进行蛋白水解以及通过各种方法对羧基或氨基进行化学修饰，消除了DIIIa的结膜致敏性，而皮肤致敏性仍然保留。因此，结膜反应的表达预计由DIIIa蛋白质部分中一个相对较小的结构因子支持，我们暂时将其称为结膜致敏性支持因子（CASF）。CASF可能有助于抗原渗透到黏膜中，使碳水化合物表位能够与分布在结膜和支气管中的过敏特异性IgE相互作用。在兔抗DIIIa血清的特异性分析中，DIIIa蛋白质部分中一个高碘酸盐氧化和酸稳定但热和碱不稳定的表位（γ型）也被鉴定为该抗原的一个有用标记。然而，γ型表位显然独立于对碱和热基本稳定的CASF。
