Generating aptamers for recognition of virus-infected cells

BACKGROUND: The development of molecular probes capable of recognizing virus-infected cells is essential to meet the serious clinical, therapeutic, and nationalsecurity challenges confronting virology today. We report the development of DNA aptamers as probes for the selective targeting of virus-infected living cells. METHODS: To create aptamer probes capable of recognizing virus-infected cells, we used cell-SELEX (systematic evolution of ligands via exponential enrichment), which uses intact infected live cells as targets for aptamer selection. In this study, vaccinia virus- infected and -uninfected lung cancer A549 cells were chosen to develop our model probes. RESULTS: A panel of aptamers has been evolved by means of the infected cell-SELEX procedure. The results demonstrate that the aptamers bind selectively to vaccinia virus-infected A549 cells with apparent equilibrium dissociation constants in the nanomolar range. In addition, these aptamers can specifically recognize a variety of target infected cell lines. The aptamers' target is most likely a viral protein located on the cell surface. CONCLUSIONS: The success of developing a panel of DNA-aptamer probes capable of recognizing virusinfected cells via a whole living cell-SELEX selection strategy may increase our understanding of the molecular signatures of infected cells. Our findings suggest that aptamers canbedevelopedas molecular probes for use as diagnostic and therapeutic reagents and for facilitating drug delivery against infected cells.