title: Expression and characterization of recombinant interleukin-21 receptor and its targeting single-chain variable fragment antibodies selected from a human phage display library.
abstract: Interleukin-21 receptor (IL-21R) is widely expressed in lymphocytes, and plays an important role in immunological cell proliferation and cytokine production. The present study aims to express a recombinant extracellular domain of human IL-21R (rhIL-21R-ECD) with high yield, and to screen the anti-IL-21R single-chain variable fragments (scFvs) from a synthetic human phage display library. The rhIL-21R-ECD, being expressed mainly as insoluble inclusion bodies in Escherichia coli BL21 (DE3), was purified and refolded. ELISA analysis showed that the refolded rhIL-21R-ECD bound to its ligand IL-21 in a concentration-dependent manner. Using a phage display technique, anti-IL-21R scFvs were screened from a naïve human phage display library by biopanning. After four rounds of panning, positive clones were isolated, sequenced, and characterized. The clone with highest activity was designated as C2. Flow cytometry analysis showed that the scFv C2 could recognize IL-21R on Jurkat cells. Furthermore, proliferation assay revealed a concentration-dependent inhibitory effect of C2 on the Jurkat cell, with fifty percent inhibitory concentration (IC(50)) of 78 nM. A human scFv antibody C2 with a high binding specificity to IL-21R was isolated and characterized. The antibody showed a concentration-dependent inhibitory effect on Jurkat cell proliferation.
authors: School of Life Science & Technology, China Pharmaceutical University, Nanjing, P.R. China.
authors: Qinhang
authors: Q
authors: Wu
authors: Juan
authors: J
authors: Zhang
authors: Chen
authors: C
authors: Luo
authors: Tao
authors: T
authors: Zhang
authors: Tong
authors: T
authors: Wang
authors: Min
authors: M
authors: Wang
mesh_terms: D049109:Cell Proliferation / Q000187:drug effects*; D061505:Cell Surface Display Techniques; D004926:Escherichia coli / Q000378:metabolism; D006801:Humans; D002479:Inclusion Bodies; D019169:Jurkat Cells; D017510:Protein Folding; D053655:Receptors, Interleukin-21 / Q000187:drug effects* / Q000276:immunology; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology / Q000494:pharmacology*; D057127:Single-Chain Antibodies / Q000096:biosynthesis / Q000276:immunology / Q000494:pharmacology*
chemical_list: D053655:Receptors, Interleukin-21; D011994:Recombinant Proteins; D057127:Single-Chain Antibodies