Cell-SELEX-based selection and characterization of a G-quadruplex DNA aptamer against mouse dendritic cells

Targeting of dendritic cells (DCs) by aptamers increases antigen capture and presentation to the immune system. Our aim was to produce aptamers against DC molecules using the cell-SELEX procedure. For this purpose, 18 rounds of cell-SELEX were performed on mouse macrophage J774A.1 and CT26 as target and control cells, respectively. The selected aptamers were truncated and their binding to mouse macrophages, and immature and mature DCs analyzed. Two macrophage-specific aptamers, Seq6 and Seq7, were identified. A truncated form of Seq7, Seq7-4, 33 nucleotides in length and containing the G-quadruplex, bound macrophages and immature DCs with KD values in the nanomolar range. We anticipate that Seq7-4 has potential as a therapeutic tool in targeting of mouse macrophages and immature DCs to efficiently improve different immunotherapy approaches.