Department of Radioimmunology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany.
Corporación para la Investigación de la Corrosión (CIC), Piedecuesta 681011, Colombia.
Int J Mol Sci. 2021 Nov 7;22(21):12046. doi: 10.3390/ijms222112046.
The anti-La mab 312B, which was established by hybridoma technology from human-La transgenic mice after adoptive transfer of anti-human La T cells, immunoprecipitates both native eukaryotic human and murine La protein. Therefore, it represents a true anti-La autoantibody. During maturation, the anti-La mab 312B acquired somatic hypermutations (SHMs) which resulted in the replacement of four aa in the complementarity determining regions (CDR) and seven aa in the framework regions. The recombinant derivative of the anti-La mab 312B in which all the SHMs were corrected to the germline sequence failed to recognize the La antigen. We therefore wanted to learn which SHM(s) is (are) responsible for anti-La autoreactivity. Humanization of the 312B ab by grafting its CDR regions to a human Ig backbone confirms that the CDR sequences are mainly responsible for anti-La autoreactivity. Finally, we identified that a single amino acid replacement (D > Y) in the germline sequence of the CDR3 region of the heavy chain of the anti-La mab 312B is sufficient for anti-La autoreactivity.
抗-La mab 312B 是通过对人源 La 转基因小鼠的抗人 La T 细胞进行过继转移，然后利用杂交瘤技术建立的，它可以免疫沉淀天然的真核人源和鼠源 La 蛋白。因此，它代表了一种真正的抗-La 自身抗体。在成熟过程中，抗-La mab 312B 获得了体细胞超突变（SHM），导致互补决定区（CDR）中的四个氨基酸和框架区中的七个氨基酸被替换。将抗-La mab 312B 的重组衍生物中的所有 SHM 都纠正为种系序列，该衍生物无法识别 La 抗原。因此，我们想了解哪些 SHM 负责抗-La 自身反应性。通过将 312B ab 的 CDR 区域嫁接到人 Ig 骨架上实现了该抗体的人源化，证实 CDR 序列主要负责抗-La 自身反应性。最后，我们发现抗-La mab 312B 重链 CDR3 区域的种系序列中单个氨基酸替换（D > Y）足以导致抗-La 自身反应性。
