Delivering DNA into B cells

Singaporean scientists have developed a strategy to deliver foreign DNA into B cells - a group of infection-fighting white blood cells in the immune system that have proven extremely difficult to transfect without the use of dangerous viruses. Their study has been published in Biotechnology Journal.

The process of transfection - introducing foreign DNA into human cells - allows scientists to study gene expression in the laboratory and enables clinicians to treat genetic diseases. The research team, led by scientists at the A*STAR Bioprocessing Technology Institute and the A*STAR Institute of High Performance Computing, successfully introduced genes into B cells by optimising a technique called sonoporation.

Sonoporation combines ultrasonic sound frequencies and tiny gas-filled bubbles to generate transient pores in the cell membrane through which DNA can travel. Study leader Andre Boon-Hwa Choo and his colleagues tweaked the acoustic energy levels and microbubble concentrations to deliver a circular piece of DNA that they could track visually in a trio of human B cell lines.

“Our work is the first to demonstrate the use of sonoporation as an alternative, non-viral method for stable and highly efficient transfection of recalcitrant B cell lines,” said Choo.

In one cell line, the researchers achieved around 43% transfection efficiency through sonoporation, compared to just 3% with a conventional transfection method called lipofection. Through further selection techniques, the researchers enriched the population of transfected B cells to more than 70%. They achieved similarly impressive results with the two other B cell lines.

According to co-first-author Charlene Li Ling Yong, the transfection technique “allows scientists to elucidate the biological pathways of immune responses”. She said it can be used in the laboratory to better understand how B cells regulate immune responses against pathogens.

Dave Siak-Wei Ow, the study’s other co-first-author, added that the method could offer “a safer and non-invasive alternative to existing gene therapies”. Numerous clinical research teams are pursuing B-cell-based gene therapies to induce tolerance against autoimmune diseases, and the technique has the potential to be applied in vivo without any of the adverse effects of viral-mediated gene therapy.