A multivalent recombinant antibody fragment specific for carcinoembryonic antigen

Area of Science:

• Biotechnology
• Oncology
• Immunology

Background:

• Carcinoembryonic antigen (CEA) is a tumor marker.
• Monoclonal antibodies (mAbs) are used for cancer diagnosis.
• Development of targeted antibody fragments is crucial for improved cancer therapies.

Purpose of the Study:

• To develop a bivalent single-chain variable fragment (scFv) antibody targeting CEA.
• To evaluate the expression, purification, and binding characteristics of the CEA-specific diabody.
• To assess the in vivo biodistribution and tumor localization of the developed antibody fragment.

Main Methods:

• Development of a bivalent scFv diabody from a mouse anti-CEA mAb.
• Expression in Escherichia coli and purification using immobilized metal ion affinity chromatography and gel filtration.
• In vivo biodistribution studies in athymic nude mice bearing human CEA+ tumors using 125I-labeled diabody.

Main Results:

• The CEA-specific diabody was successfully expressed in E. coli and purified.
• The diabody demonstrated high affinity and specificity for CEA, comparable to the parent mAb.
• Biodistribution studies showed preferential localization and high retention in CEA+ tumors 48 hours post-injection.

Conclusions:

• The developed bivalent scFv diabody is a highly specific and effective CEA-targeting agent.
• Its favorable biodistribution profile suggests potential for in vivo tumor targeting applications.
• The smaller molecular mass offers advantages like faster clearance for improved in vivo applications.