B Lymphocytes, or B cells, are a type of white blood cell that play a crucial role in the immune system. They are responsible for producing antibodies, which are proteins that help identify and neutralize pathogens like bacteria and viruses. B cells develop in the bone marrow and can recognize specific antigens, allowing them to target particular threats. When activated by an infection, B cells can differentiate into plasma cells, which produce large amounts of antibodies. Some B cells also become memory cells, providing long-term immunity by remembering past infections. This ability is essential for the effectiveness of vaccines, which train the immune system to recognize specific pathogens.