What type of cells are responsible for creating antibodies that attack invading bacteria and viruses?

B cells are a type of white blood cell that play a crucial role in the adaptive immune response. Their primary function is to produce antibodies, which are specific proteins that can bind to antigens - the unique markers found on invading pathogens such as bacteria and viruses. When B cells encounter an antigen that matches their specific receptor, they become activated and proliferate. Some of these activated B cells differentiate into plasma cells, which are specialized in producing large amounts of antibodies. These antibodies then circulate in the bloodstream and lymphatic system, where they can neutralize pathogens, mark them for destruction by other immune cells, or prevent them from entering cells.

This process is essential for the recognition and elimination of pathogens that the body has encountered before, thereby providing long-term immunity. Other types of cells mentioned, such as T cells, macrophages, and neutrophils, have different roles in the immune response, focusing on direct attack or phagocytosis rather than antibody production.