Developing a drug or vaccine requires a delicate balancing act with the immune system. On one hand, medications need to escape detection by the immune system in order to perform their function. But vaccinations — de-activated versions of a disease or virus — need to do the reverse. They prompt the immune system to create protective antibodies. But scientists are still stumped by how the immune system recognizes different particles, and how it chooses whether or not to react against them. Continue reading →