Regulatory T cells help to modulate the immune system, and those that express a protein called LAP are particularly potent suppressors of immune responses to cancer. The cells have been linked to poor outcomes in people with the disease. Howard Weiner at Brigham and Women’s Hospital in Boston, Massachusetts, and his colleagues have found a way to target these cells with an antibody that lowers LAP levels.
Treatment with the antibody diminished tumour growth in mice, and improved the effectiveness of an anti-cancer vaccine. Four months after treatment, the antibody had increased the number of CD8+ T cells, which are involved in immune memory. This suggests that inhibiting LAP could enhance the immune system’s ability to quickly recognize and respond to cancer cells.