Image by Kathryn T. Iacono
Researchers say they have devised a method for harvesting regulatory T cells (Tregs) on a large scale, and they are currently testing these Tregs in a trial of patients with graft-versus-host disease (GVHD).
The team described the harvesting method in the Journal of Immunotherapy.
“A Tregs-based therapy could help reduce the risk of GVHD, but Tregs are a very rare population amongst blood cells,” said study author Sebastian Bertin-Maghit, PhD, of the Agency for Science, Technology and Research (A*STAR) in Singapore.
“For our therapy to work, we needed a large supply of pure, ‘untouched’ Tregs that are uncontaminated with other cell types.”
However, when it came to isolating pure Tregs on a large scale, the researchers found existing isolation methods inefficient.
So rather than isolating the cells by “plucking” them out of a donor sample—a method that comes with the risk of unwanted modification or activation of some cells—the team devised a depletion method for selecting Tregs in their pure, untouched state.
“We depleted all unwanted cells in donor samples using isolation reagents,” Dr Bertin-Maghit said. “This allowed us to harvest Tregs in their natural state. We took great care to wash out the isolation reagents in the final product.”
The researchers have since proven that this single-step depletion process can be scaled up to harvest highly pure Tregs at levels suitable for clinical trials, and their procedure complies with current trial standards.
Furthermore, while previous attempts to collect Tregs produced a final product with 60% pure Tregs, this new method generates over 90% pure Tregs.
“The first clinical trial using our Treg product is currently ongoing at the Singapore General Hospital,” Dr Bertin-Maghit said. “We are assessing the safety of Tregs in the treatment of GVHD in 12 leukemia patients. We believe our procedure will open doors to a new era in cell therapy.”
