Development of Single-Chain Antibodies Specific to Lysophosphatidic Acid Receptor 2

• Published in: Bulletin of the Korean Chemical Society 2018, Vol.39 (4), p.489-494
• Main Authors: Son, Sang Hyeon, Baek, Seung-il, Ju, Man-Seok, Han, Seong-Gu, Jung, Sang Taek, Yu, Yeon Gyu
• Format: Article
• Language: Korean
• ISSN: 0253-2964; 1229-5949

Lysophosphatidic acids (LPAs) are ubiquitous serum phospholipids that trigger diverse cellular responses such as cell proliferation, migration, cell survival, and calcium influx. LPA receptors belong to the G-protein coupled receptor (GPCR) family, and seven subtypes of LPA receptors have been identified. Among them, LPA receptor 2 ($LPA_2$) is involved in the proliferation and metastasis of ovarian, cervical, and breast cancers. Hence, $LPA_2$-specific antagonists or antibodies are considered as potential anticancer therapeutics. To develop antibodies against $LPA_2$, a recombinant $LPA_2$ was expressed in Escherichia coli, purified to homogeneity, and immobilized on a solid surface as an active conformation. An M13 phage library displaying single-chain variable fragments (scFvs) of human IgG containing randomized complementarity-determining regions was applied to select $LPA_2$-specific scFv clones. After five rounds of biopanning, a few scFv clones which showed specific binding to $LPA_2$ were identified. Single-chain antibodies (scAbs), which contain the isolated scFvs and $C_{\kappa}$ domain, were constructed and expressed in E. coli. The purified scAbs showed specific binding to $LPA_2$ with $K_D$ values of 200-600 nM.