Engineered human FcγRIIa fusion: A novel strategy to extend serum half-life of therapeutic proteins

Migyeong Jo, Sanghwan Ko, Bora Hwang, Sung Won Min, Ji Yeon Ha, Ji Chul Lee, Se Eun Jang, Sang Taek Jung

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


The immunoglobulin G (IgG) molecule has a long circulating serum half-life (~3 weeks) through pH- dependent FcRn binding-mediated recycling. To hijack the intracellular trafficking and recycling mechanism of IgG as a way to extend serum persistence of non-antibody therapeutic proteins, we have evolved the ectodomain of a low-affinity human FcγRIIa for enhanced binding to the lower hinge and upper CH2 region of IgG, which is very far from the FcRn binding site (CH2–CH3 interface). High-throughput library screening enabled isolation of an FcγRIIa variant (2A45.1) with 32-fold increased binding affinity to human IgG1 Fc (equilibrium dissociation constant: 9.04 × 10−7 M for wild type FcγRIIa and 2.82 × 10−8 M for 2A45.1) and significantly improved affinity to mouse serum IgG compared to wild type human FcγRIIa. The in vivo pharmacokinetic profile of PD-L1 fused with engineered FcγRIIa (PD-L1–2A45.1) was compared with that of PD-L1 fused with wild type FcγRIIa (PD-L1–wild type FcγRIIa) and human PD-L1 in mice. PD-L1–2A45.1 showed 11.7- and 9.7-fold prolonged circulating half-life (t1/2) compared to PD-L1 when administered intravenously and intraperitoneally, respectively. In addition, the AUCinf of PD-L1–2A45.1 was two-fold higher compared to that of PD-L1–wild type FcγRIIa. These results demonstrate that engineered FcγRIIa fusion offers a novel and successful strategy for prolonging serum half-life of therapeutic proteins.

Original languageEnglish
Pages (from-to)2351-2361
Number of pages11
JournalBiotechnology and Bioengineering
Issue number8
Publication statusPublished - 2020 Aug 1

Bibliographical note

Funding Information:
This study was supported by a Korea University Medical Center Grant and grants from the Basic Science Research Program (2019R1F1A1059834 and 2019R1A4A1029000), the Bio & Medical Technology Development Program (2017M3A9C8060541) through the National Research Foundation of Korea funded by the Ministry of Science and ICT.

Publisher Copyright:
© 2020 Wiley Periodicals LLC


  • directed evolution
  • human FcRn
  • human FcγRIIa
  • serum half-life
  • therapeutic protein

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology


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