Ligand-Guided Selection of Target-Specific Aptamers: A Screening Technology for Identifying Specific Aptamers Against Cell-Surface Proteins

Nucleic Acid Ther. 2016 Jun;26(3):190-8. doi: 10.1089/nat.2016.0611. Epub 2016 May 5.

Abstract

We report on a new strategy for identifying highly specific aptamers against a predetermined epitope of a target. Termed "ligand-guided selection" (LIGS), this method uniquely exploits the selection step, the core of SELEX (Systematic Evolution Exponential enrichment). LIGS uses a naturally occurring stronger and highly specific bivalent binder, an antibody (Ab) interacting with its cognate antigen to outcompete specific aptamers from a partially enriched SELEX pool, as a strategy. We demonstrate the hypothesis of LIGS by utilizing an Ab binding to membrane-bound Immunoglobulin M (mIgM) to selectively elute aptamers that are specific for mIgM from a SELEX pool that is partially enriched toward mIgM expressing Ramos cells. The selected aptamers show specificity toward Ramos cells. We identified three aptamer candidates utilizing LIGS that could be outcompeted by mIgM Ab, demonstrating that LIGS can be successfully applied to select aptamers from a partially evolved cell-SELEX library, against predetermined receptor proteins using a cognate ligand. This proof-of-concept study introduces a new biochemical-screening platform that exploits the binding of a secondary stronger molecular entity to its target as a partition step, to identify highly specific artificial nucleic acid ligands.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Aptamers, Nucleotide / genetics
  • Aptamers, Nucleotide / isolation & purification*
  • Epitope Mapping
  • Humans
  • Immunoglobulin M / genetics
  • Immunoglobulin M / immunology
  • Ligands
  • Membrane Proteins / genetics*
  • Membrane Proteins / immunology
  • Membrane Proteins / therapeutic use
  • Protein Binding
  • Receptors, Antigen, B-Cell / genetics
  • Receptors, Antigen, B-Cell / immunology
  • Receptors, Antigen, B-Cell / isolation & purification*
  • SELEX Aptamer Technique*

Substances

  • Aptamers, Nucleotide
  • Immunoglobulin M
  • Ligands
  • Membrane Proteins
  • Receptors, Antigen, B-Cell