7SFX

10A1 Fab in complex with CD99 peptide

7SFX の概要

• エントリーDOI: 10.2210/pdb7sfx/pdb
• 分子名称: 10A1 Fab heavy chain, 10A1 Fab light chain, CD99 antigen peptide, ... (4 entities in total)
• 機能のキーワード: tumor antigen, cytotoxic antibody, complex, immune system
• 由来する生物種: Homo sapiens (Human); 詳細
• タンパク質・核酸の鎖数: 10
• 化学式量合計: 201859.37

構造登録者

Romero, L.A.,Hattori, T.,Koide, S. (登録日: 2021-10-04, 公開日: 2021-12-29, 最終更新日: 2024-11-20)

主引用文献

Romero, L.A.,Hattori, T.,Ali, M.A.E.,Ketavarapu, G.,Koide, A.,Park, C.Y.,Koide, S.
High-valency Anti-CD99 Antibodies Toward the Treatment of T Cell Acute Lymphoblastic Leukemia.
J.Mol.Biol., 434:167402-167402, 2021

PubMed Abstract: T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive form of leukemia that currently requires intensive chemotherapy. While childhood T-ALL is associated with high cure rates, adult T-ALL is not, and both are associated with significant short- and long-term morbidities. Thus, less toxic and effective strategies to treat T-ALL are needed. CD99 is overexpressed on T-ALL blasts at diagnosis and at relapse. Although targeting CD99 with cytotoxic antibodies has been proposed, the molecular features required for their activity are undefined. We identified human antibodies that selectively bound to the extracellular domain of human CD99, and the most potent clone, 10A1, shared an epitope with a previously described cytotoxic IgM antibody. We engineered clone 10A1 in bivalent, trivalent, tetravalent, and dodecavalent formats. Increasing the antibody valency beyond two had no effects on binding to T-ALL cells. In contrast, a valency of ≥3 was required for cytotoxicity, suggesting a mechanism of action in which an antibody clusters ≥3 CD99 molecules to induce cytotoxicity. We developed a human IgG-based tetravalent version of 10A1 that exhibited cytotoxic activity to T-ALL cells but not to healthy peripheral blood cells. The crystal structure of the 10A1 Fab in complex with a CD99 fragment revealed that the antibody primarily recognizes a proline-rich motif (PRM) of CD99 in a manner reminiscent of SH3-PRM interactions. This work further validates CD99 as a promising therapeutic target in T-ALL and defines a pathway toward the development of a selective therapy against T-ALL.

PubMed: 34958778
DOI: 10.1016/j.jmb.2021.167402

実験手法

X-RAY DIFFRACTION (3.1 Å)