Protease-activation using anti-idiotypic masks enables tumor specificity of a folate receptor 1-T cell bispecific antibody

Nat Commun. 2020 Jun 24;11(1):3196. doi: 10.1038/s41467-020-16838-w.

Abstract

T-cell bispecific antibodies (TCBs) crosslink tumor and T-cells to induce tumor cell killing. While TCBs are very potent, on-target off-tumor toxicity remains a challenge when selecting targets. Here, we describe a protease-activated anti-folate receptor 1 TCB (Prot-FOLR1-TCB) equipped with an anti-idiotypic anti-CD3 mask connected to the anti-CD3 Fab through a tumor protease-cleavable linker. The potency of this Prot- FOLR1-TCB is recovered following protease-cleavage of the linker releasing the anti-idiotypic anti-CD3 scFv. In vivo, the Prot-FOLR1-TCB mediates antitumor efficacy comparable to the parental FOLR1-TCB whereas a noncleavable control Prot-FOLR1-TCB is inactive. In contrast, killing of bronchial epithelial and renal cortical cells with low FOLR1 expression is prevented compared to the parental FOLR1-TCB. The findings are confirmed for mesothelin as alternative tumor antigen. Thus, masking the anti-CD3 Fab fragment with an anti-idiotypic mask and cleavage of the mask by tumor-specific proteases can be applied to enhance specificity and safety of TCBs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Bispecific / chemistry
  • Antibodies, Bispecific / immunology*
  • Antibodies, Bispecific / metabolism*
  • Antibodies, Bispecific / therapeutic use
  • CD3 Complex / immunology*
  • Cell Line, Tumor
  • Folate Receptor 1 / immunology*
  • GPI-Linked Proteins / immunology
  • Humans
  • Immunotherapy
  • Lymphocyte Activation / drug effects
  • Mesothelin
  • Mice
  • Molecular Targeted Therapy
  • Peptide Hydrolases / metabolism*
  • T-Lymphocytes / immunology*
  • Xenograft Model Antitumor Assays

Substances

  • Antibodies, Bispecific
  • CD3 Complex
  • FOLR1 protein, human
  • Folate Receptor 1
  • GPI-Linked Proteins
  • Msln protein, mouse
  • Peptide Hydrolases
  • Mesothelin