Byfield P G, Clingan D, Himsworth R L
Biochem J. 1984 Apr 15;219(2):405-10. doi: 10.1042/bj2190405.
Human thyroglobulin (Tg) could be adsorbed through one of its thyroxine (T4) residues by either of two T4-binding antibodies which had been covalently attached to Sepharose- CL4B . The antibodies used were (i) a purified human autoantibody specific for a T4-containing epitope in human Tg, or (ii) a rabbit antibody raised against T4 conjugated to bovine albumin side chains. Tg adsorbed by either immobilized antibody could then itself adsorb either type of antibody free in solution on to a further T4 residue. At least two T4 residues in human Tg are therefore sufficiently exposed to interact with T4-binding antibodies. Furthermore, these T4 residues are sufficiently far apart to allow the binding of two immunoglobulin molecules simultaneously. Previous observations of a marked preference by human autoantibodies for one of the T4-containing epitopes in Tg therefore reflect a higher binding energy with that epitope rather than an inability to interact with others. The T4-containing epitope which preferentially reacts with human Tg autoantibodies must therefore have a distinctive topography.
人甲状腺球蛋白（Tg）可通过其甲状腺素（T4）残基之一，被两种已共价连接到琼脂糖CL4B上的T4结合抗体中的任何一种吸附。所用抗体为：（i）一种纯化的针对人Tg中含T4表位的人自身抗体，或（ii）一种针对与牛白蛋白侧链偶联的T4产生的兔抗体。被固定化抗体吸附的Tg随后自身可将溶液中游离的任何一种抗体吸附到另一个T4残基上。因此，人Tg中至少有两个T4残基充分暴露，可与T4结合抗体相互作用。此外，这些T4残基相距足够远，能允许两个免疫球蛋白分子同时结合。因此，先前观察到的人自身抗体对Tg中含T4表位之一有明显偏好，这反映了与该表位有更高的结合能，而非无法与其他表位相互作用。因此，优先与人Tg自身抗体反应的含T4表位必定具有独特的拓扑结构。
