Generation of humanized single-chain fragment variable immunotherapeutic against EGFR variant III using baculovirus expression system and in vitro validation

Int J Biol Macromol. 2019 Mar 1;124:17-24. doi: 10.1016/j.ijbiomac.2018.11.202. Epub 2018 Nov 22.


Epidermal growth factor receptor variant III (EGFRvIII) is known to be specifically expressed in cancer cells and associated with tumor virulence. The receptor provides an opportunity for both specifically targeting the tumor cells as well as for potentially controlling and inhibiting tumor progression. In this study, humanized anti-EGFRvIII single-chain fragment variable (hscFv) was expressed in insect cell culture system to accommodate post-translational glycosylations crucial for the fragment stability and efficacy. Target specific binding of the developed fragment to EGFRvIII expressing cell lines and EGFRvIII positive glioblastoma patient samples was evaluated by immunocytochemistry and immunohistochemistry respectively. Downstream intracellular signaling mechanisms related to the action of the developed antibody fragment on growth/metabolism of the cell was evaluated in U87-EGFRvIII human glioblastoma cell lines. It was observed that the hscFv bound specifically to EGFRvIII in mutant expressing cells. Functionally, hscFv was found to confer anti-proliferative properties in EGFRvIII expressing cell lines by downregulating phosphorylation of EGFR/EGFRvIII, Lyn, PI3K and GLUT3 involved in proliferation and metabolism. This study demonstrated the significance of hscFv as a potential immunotherapeutic agent as well as a targeting agent for specific delivery of drugs to EGFRvIII expressing cancer cells.

Keywords: Baculovirus expression; EGFRvIII; Glioblastoma; scFv.

MeSH terms

  • Antibodies, Anti-Idiotypic / immunology
  • Antibodies, Anti-Idiotypic / therapeutic use
  • Antibodies, Monoclonal, Humanized / immunology
  • Antibodies, Monoclonal, Humanized / therapeutic use
  • Baculoviridae / genetics
  • Cell Line, Tumor
  • Cell Proliferation / genetics
  • ErbB Receptors / immunology
  • ErbB Receptors / therapeutic use
  • Gene Expression Regulation / immunology
  • Glioblastoma / immunology*
  • Glioblastoma / therapy
  • Glucose Transporter Type 3 / genetics
  • Humans
  • Immunotherapy*
  • Phosphorylation
  • Single-Chain Antibodies / biosynthesis
  • Single-Chain Antibodies / immunology*
  • Single-Chain Antibodies / therapeutic use


  • Antibodies, Anti-Idiotypic
  • Antibodies, Monoclonal, Humanized
  • Glucose Transporter Type 3
  • SLC2A3 protein, human
  • Single-Chain Antibodies
  • EGFR protein, human
  • ErbB Receptors