Belgian scientists have uncovered new details about how the immune system responds to vaccines. Dendritic cells, which are key immune messengers that help kick-start the body’s defenses, show specific responses to lipid nanoparticles. These findings, published in Cell Reports, could lead to safer and more effective vaccines.

Dendritic cells are among the first to detect viruses, bacteria, or other immune challenges. These cells help coordinate the immune system’s response by alerting T cells, the immune system’s soldiers trained to eliminate threats. But dendritic cells don’t always respond in the same way. Some keep the immune system calm and balanced (homeostatic), while others drive a full immune attack (immunogenic).

Until now, little was known about what determines these different responses, especially when dendritic cells encounter vaccines.