Targeted transfer of polyethylenimine-avidin-DNA bioconjugates to hematopoietic cells using biotinylated monoclonal antibodies

Here we examine whether attachment of biotinylated antibodies to proteins o n the cell surface increases the transfection efficiency of polyethylenimin e-avidin-DNA bioconjugate gene transfer. Preliminary experiments were perfo rmed to compare avidin endocytosis into cells incubated with biotinylated a ntibodies. Antibody biotinylation resulted in the endocytosis of avidin-FIT C into nearly 100% of cells compared with no detectable binding or entry in to unbiotinylated cells. Gene transfer was accomplished with avidin conjuga ted to polyethylenimine (PEI) at a molar ratio of 4:1 (PA4). Plasmid DNA en coding the green fluorescent protein (GFP) gene was condensed on the PA4, a nd transfection efficiencies were measured by flow cytometry as the percent age of cells that fluoresced at levels greater than two standard deviations above the negative control. Gene transfer efficiencies were compared among K562, HEL, and Jurkat leukemia cell lines. Control transfections with DNA alone or untargeted PEI-DNA resulted in less than or equal to 2% GFP positi ve cells. Targeting PEI-avidin-DNA to antibody biotinylated cells increased transfection efficiency several fold over untargeted PEI. For each cell ty pe, the increase in transfection efficiency was not significantly different among four biotinylated antibodies tested (antiCD55, antiCD59, antiCD71, a nd antiCD98). These data suggest biotinylated antibodies may be useful for targeting polyethylenimine-avidin mediated gene transfer. (C) 2000 Wiley-Li ss, Inc.