Quantification of DNA binding to cell-surfaces by flow cytometry

DNA binding to cell-surfaces has been documented in several studies. The interaction of DNA with cells has been shown to have therapeutic potential as a non-viral form of gene delivery and DNA vaccination. Recently, bacterial DNA binding and internalization has been demonstrated in some cells to trigger secretion of cytokines and cell activation. Previous studies to quantify DNA binding to cells have used radiolabeled DNA. Here we report a non-radioactive assay for quantification of cell-surface DNA binding based on the isoparametric analysis of flow cytometric data as described by Chatelier et al., Embo J., 5 (1986) 1181. This assay has the advantage over previously used procedures in not employing radioactive material and being able to discriminate viable from non-viable cells that bind DNA. With the importance of understanding the interaction of DNA with cells, this assay may have application for the identification and characterization of reagents designed to either enhance or inhibit DNA binding to cells.