Immune cells are specialized cells in the body that help protect against infections and diseases. They are part of the immune system, which identifies and attacks harmful invaders like bacteria, viruses, and parasites. Key types of immune cells include T cells, B cells, and macrophages, each playing a unique role in defending the body. T cells help recognize and destroy infected cells, while B cells produce antibodies that neutralize pathogens. Macrophages engulf and digest foreign substances. Together, these immune cells work in harmony to maintain health and respond to threats, ensuring the body can fight off infections effectively.