Development of a Subtype-Specific Diagnostic System for Influenza Virus H3N2 Using a Novel Virus-Based Systematic Evolution of Ligands by Exponential Enrichment (Viro-SELEX).

Aptamers are oligonucleotide molecules that bind to specific target molecules generated by systematic evolution of ligands by exponential enrichment (SELEX). Aptamers have high future potential for use in diagnostics and therapeutics as molecular probes that recognize target molecules. To develop aptamers against a target protein using a SELEX process, it is necessary to purify the target protein. Purifying a membrane protein, however, is usually a challenging task. Here, we report a novel approach to developing aptamers against membrane proteins. Surrogate viruses containing target proteins on the surface of an enveloped virus (e.g., baculovirus), instead of purified proteins, were used in a new SELEX process. We designated this new SELEX process as "surrogate virus-based SELEX (viro-SELEX)." Using viro-SELEX, we developed a pair of aptamers that specifically interact with the hemagglutinin protein of influenza subtype H3N2. Using the aptamer pair and a lateral flow assay system, we developed a very sensitive point-of-care diagnostic system for specifically detecting influenza virus subtype H3N2.