Discovery of Aptamers Against Cell Surface Markers Using Ligand-Guided Selection

Area of Science:

• Biotechnology
• Molecular Biology
• Immunology

Background:

• Systematic evolution of ligands by exponential enrichment (SELEX) is an iterative process for selecting oligonucleotide ligands (aptamers) against target molecules.
• Selecting aptamers against cell surface proteins in their native state presents challenges.
• Ligand-guided selection (LIGS) is a variant of SELEX designed to overcome these challenges.

Purpose of the Study:

• To describe the detailed methodology of LIGS.
• To identify aptamers targeting the T-cell receptor cluster of differentiation three complex (TCR-CD3).
• To demonstrate LIGS utility in selecting aptamers against cell surface proteins on human T-cells and T-cell leukemia.

Main Methods:

• LIGS exploits the SELEX selection step by introducing a secondary ligand (e.g., monoclonal antibody) to guide aptamer selection.
• The secondary ligand competes with aptamers or induces conformational changes to destabilize aptamer-target interactions.
• This process facilitates the elution of specific aptamer sequences targeting cell surface proteins.

Main Results:

• The study details the LIGS protocol for aptamer selection.
• Aptamers were successfully identified against the T-cell receptor cluster of differentiation three complex (TCR-CD3).
• The method is effective for selecting aptamers against native cell surface targets on human T-cells and leukemia cells.

Conclusions:

• Ligand-guided selection (LIGS) is a powerful technique for developing highly specific aptamers against cell surface targets.
• The described LIGS method enables the identification of aptamers for TCR-CD3, relevant for T-cell research and diagnostics.
• LIGS offers a significant advancement for aptamer selection against complex biological targets in their native cellular context.