Summary of work The T-cell growth factor IL-2 plays an important role in helping activated T-cells persist and expand so that they can fight diseases such as cancer. This makes IL-2 a potentially powerful ally when paired with anti-tumor T-cell therapies, such as CAR-T. However, IL-2 can also cause serious side effects, limiting its use in the clinic. In this paper, researchers engineered a synthetic IL-2 receptor system that in mice effectively boosted T-cell growth in vivo and in vitro, while limiting off-target effects and toxicity. Parker Institute project member K. Christopher Garcia, PhD, of Stanford University, is senior author. He collaborated with co-authors Jeffrey Bluestone, PhD, Parker Institute president and CEO, and Antoni Ribas, MD, PhD, Parker Institute director at UCLA. Why this is impactful to patients “T-cell expansion and persistence remains a significant challenge in the field of T-cell therapy,” said Samantha Bucktrout, PhD, director of research at the Parker Institute. “To solve that problem, the investigators developed a novel approach using IL-2 that boosts T-cell growth and activity but should minimize side effects.”