The main role of white blood cells is to defend the body against infections and diseases. These cells are a crucial component of the immune system, identifying and destroying pathogens such as bacteria, viruses, and other harmful agents. There are different types of white blood cells, each with specific functions, such as lymphocytes, which produce antibodies, and phagocytes, which engulf and digest foreign invaders. A robust immune response is vital for maintaining health and preventing illness.