Immune cells are specialized cells in the body that help protect against infections and diseases. They are part of the immune system, which works to identify and eliminate 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 the immune response. When the body detects a threat, immune cells spring into action. T cells can directly kill infected cells, while B cells produce antibodies that neutralize pathogens. Macrophages engulf and digest foreign particles, helping to clear infections. Together, these cells coordinate a defense to keep the body healthy.