B-Cell Receptors (BCRs) are specialized proteins found on the surface of B cells, a type of white blood cell. They play a crucial role in the immune system by recognizing and binding to specific antigens, which are foreign substances like bacteria or viruses. This binding triggers the activation of B cells, leading to their proliferation and differentiation into plasma cells that produce antibodies. Each BCR is unique, allowing the immune system to target a wide variety of pathogens. When a BCR binds to its specific antigen, it initiates a signaling cascade that helps the B cell respond effectively. This process is essential for developing immunity and forming memory B cells that provide long-term protection against future infections.