CD27 boost could unlock long-lasting cancer vaccine immunity

A 20-year-old breast cancer vaccine trial shows all participants are still alive decades later, suggesting durable immune memory. Researchers found persistent CD27-marked CD4+ T cells can recognize the cancer, hinting that CD27 could make cancer vaccines more effective. In mice, combining the vaccine with a CD27-activating antibody nearly doubled tumor elimination (about 40% complete responses vs 6% with vaccine alone); adding extra support for CD8+ T cells pushed tumor rejection to ~90%. These findings imply CD27 could be a key addition to cancer vaccines and compatible with existing therapies.