Penn State Sep 3 2025 The body has an intricate system to defend against infections where each type of immune cell plays a distinct role. Now, a study led by researchers from the Penn State College of Medicine has uncovered a new function of the immune cells that are known for making antibodies. They determined that, in response to flu infection, a specialized set of B cells produce a key signaling molecule that the immune system needs to develop a robust, long-term response to fight off