💉 A former cancer vaccine, misunderstood at the time, shows formidable efficacy

How could patients with advanced breast cancer survive more than twenty years after a simple vaccine trial? This medical observation piqued the curiosity of scientists, who decided to reexamine the case of these women. Their exceptional survival led to an in-depth investigation to decipher the immune mechanisms at work.

A team from Duke University analyzed the immune system of these former participants. They discovered that their bodies retained immune cells capable of recognizing cancer cells after all these years. These cells exhibited a marker called CD27, associated with immune memory. The data, published in Science Immunology, indicate that targeting this marker could significantly improve the efficacy of cancer vaccines.


To evaluate this hypothesis, the team used an antibody stimulating CD27 along with a vaccine targeting the HER2 protein, involved in certain breast cancers, on mouse models. Nearly 40% of mice that received this combined treatment saw their tumors disappear completely, compared to only 6% with the vaccine alone. The researchers noted that the antibody enhanced the activity of a particular type of immune cell.

These cells, named CD4+ T cells, are often sidelined in cancer research in favor of so-called "killer" CD8+ T cells. Yet, in this research, CD4+ cells appear to play a leading role. They help maintain long-term immune memory and assist the body's other defenses so they operate more effectively against tumors.

Introducing a second antibody, designed to assist CD8+ T cells, further increased tumor rejection rates in mice, reaching nearly 90%. The scientists specify that the antibody targeting CD27 only needs to be administered once, at the same time as the vaccine, to generate a lasting effect. This characteristic could simplify its combination with other anti-cancer treatments already in use.

This method could thus offer new horizons for cancer vaccines, whose results have sometimes been modest in the past. By optimizing immune memory through cells like CD4+ T cells, it becomes conceivable to design more robust and durable therapeutic strategies. Work continues to examine potential applications in humans.