Germinal center

A germinal center is a specialized microenvironment that forms inside lymph nodes and other immune organs when your body encounters a new infection or foreign substance. Within these temporary structures, B cells (immune cells that make antibodies) rapidly multiply and undergo a rigorous selection process where only the best-performing cells survive, allowing your immune system to develop increasingly effective antibodies against the invader. This sophisticated "training ground" is why it takes a few days or weeks for your body to fully mount an immune response, but once activated, you develop antibodies finely tuned to fight off the specific threat.