Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
Immunogenetics. 2010 Jan;62(1):1-13. doi: 10.1007/s00251-009-0414-7. Epub 2009 Dec 15.
A set of mouse IgAs containing amino acids differing amongst the six alpha-chain allotypes was constructed by mutating an S107-IgA plasmid and transfecting it into a non-producer myeloma cell line along with a kappa-chain plasmid. The secreted IgAs were examined for their possession of a covalent bond between alpha- and light (L)-chains and for their ability to bind to three anti-allotypic monoclonal antibodies, HIS-M2, HY-15, and HY-16. IgA of the Igh-2(a) allotype was found to be unique in its total lack of a covalent bond between alpha and L: -chains, formation of which apparently depends on the presence of an "extra" Cys in the hinges of all of the other five allotypes. The allotypic epitopes are associated with identifiable amino acids in the Calpha1 region of the molecule. Binding to HIS-M2 requires Ala 216 whereas binding to HY-15 requires Pro 216 and Asp 222. Binding to Hy-16 requires Arg 183 and either Pro 216 or Ser 216 but not Ala 216. However, binding to HY-16 by all of the IgAs produced by transfectants is impaired by defective glycosylation in the transfected myeloma and is only revealed after deglycosylation.
一组包含六个α-重链同种异型氨基酸差异的小鼠 IgA 通过突变 S107-IgA 质粒并与 κ-链质粒一起转染到非产生细胞骨髓瘤系中构建而成。对分泌的 IgA 进行了研究，以检查其α-和轻（L）-链之间是否存在共价键，以及其是否能够与三种抗同种异型单克隆抗体 HIS-M2、HY-15 和 HY-16 结合。发现 Igh-2(a)同种异型的 IgA 完全缺乏α-和 L-链之间的共价键，这显然取决于其他五个同种异型铰链中存在“额外”Cys。同种异型表位与分子的 Calpha1 区域中的可识别氨基酸相关联。与 HIS-M2 结合需要 Ala 216，而与 HY-15 结合需要 Pro 216 和 Asp 222。与 Hy-16 结合需要 Arg 183 和 Pro 216 或 Ser 216，但不需要 Ala 216。然而，转染骨髓瘤中糖基化缺陷会损害转染细胞产生的所有 IgA 与 HY-16 的结合，只有在去糖基化后才能显示出来。
