Recombinant humanized Fab fragments targeting the CFC domain of human Cripto-1

Annamaria Sandomenico1, Fabio Selis2, Jwala P Sivaccumar1

  • 1Institute of Biostructures and Bioimaging, CNR, Via P. Castellino, 111, 80131, Napoli, Italy.

Insights

Researchers developed humanized antibody fragments targeting the Cripto-1 onco-fetal protein. These engineered Fabs can be site-specifically labeled for potential use in cancer theranostics.

Area of Science:

  • Oncology
  • Immunology
  • Biotechnology

Background:

  • Cripto-1 is an onco-fetal protein and a debated biomarker for various cancers.
  • Targeting cancer-specific biomarkers with selective reagents is crucial for immunotherapy.
  • Cripto-1 is actively investigated as a potential theranostic target due to its selective expression in solid tumors.

Purpose of the Study:

  • To engineer humanized recombinant antibody fragments (Fabs) targeting Cripto-1.
  • To create Fabs with a site-specific labeling capability for theranostic applications.
  • To characterize and validate the binding affinity of these Fabs to Cripto-1 on cancer cells.

Main Methods:

  • Humanization of anti-Cripto-1 murine monoclonal antibodies to create recombinant Fabs.
  • Engineering Fabs with an MTGase site for one-step, site-specific labeling.
  • Purification, bioconjugation, and characterization of the engineered Fabs.
  • In vitro binding assays using Cripto-1-positive cancer cells.

Main Results:

  • Successfully prepared humanized recombinant Fabs targeting Cripto-1.
  • Engineered Fabs possess a site for one-step, site-specific labeling.
  • The Fabs demonstrated binding to the native Cripto-1 antigen on intact cancer cells.
  • Extensive characterization confirmed the properties of the purified and bioconjugated molecules.

Conclusions:

  • The developed recombinant Fab fragments recognize Cripto-1 in its native form on cancer cells.
  • These engineered Fabs show promise as reagents for detecting Cripto-1 in theranostic settings.
  • Further development of these Cripto-1-targeting Fabs could advance cancer theranostics.