Highly effective recombinant format of a humanized IgG-like bispecific antibody for cancer immunotherapy with retargeting of lymphocytes to tumor cells

Ryutaro Asano, Yasuhiro Watanabe, Hiroko Kawaguchi, Hidesuke Fukazawa, Takeshi Nakanishi, Mitsuo Umetsu, Hiroki Hayashi, Yu Katayose, Michiaki Unno, Toshio Kudo, Izumi Kumagai

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)

Abstract

We previously reported the marked in vitro and in vivo antitumor activity of hEx3, a humanized diabody (small recombinant bispecific antibody) with epidermal growth factor receptor (EGFR) and CD3 retargeting. Here, we fabricated a tetravalent IgG-like bispecific antibody with two kinds of single-chain Fv (scFv), i.e. humanized anti-EGFR scFv and anti-CD3 scFv, that contains the same four variable domains as hEx3, on the platform of human IgG1 (hEx3-scFv-Fc). hEx3-scFv-Fc prepared from mammalian cells showed specific binding to both EGFR and CD3 target antigens. At one-thousandth (0.1-100 fmol/ml) of the dose of normal hEx3, hEx3-scFv-Fc showed intense cytotoxicity to an EGFR-positive cell line in a growth-inhibition assay using lymphokine-activated killer cells with the T-cell phenotype (T-LAK cells). The enhanced antitumor effect was more clearly observed when peripheral blood mononuclear cells (PBMCs) were used as effector cells, indicating the utility of IgG-like fabrication. These results suggested that the intense antitumor activity is attributable to the multivalency and the presence of the fused human Fc, a hypothesis that was supported by the results of flow cytometry, PBMC proliferation assay, and protein kinase inhibition assay. Furthermore, the growth inhibition effects of hEx3-scFv-Fc were considerably superior to those of the approved therapeutic antibody, cetuximab, which recognizes the same EGFR antigen even when using PBMCs as effector cells. The high potency of hEx3-scFv-Fc may translate into improved antitumor therapy and lower costs of production because of the smaller doses needed.

Original languageEnglish
Pages (from-to)27659-27665
Number of pages7
JournalJournal of Biological Chemistry
Volume282
Issue number38
DOIs
Publication statusPublished - 2007 Sep 21

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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