List the cells that play a major role in protecting the body from infections, and describe their functions.

The major cells involved in protecting the body from infections are: 1. Neutrophils: They are abundant white blood cells that act as a first line of defense against bacterial and fungal infections. They engulf and destroy foreign invaders by producing chemicals and enzymes that break them down. 2. Monocytes/Macrophages: Monocytes differentiate into macrophages in tissues, which are long-lived cells that play roles in tissue homeostasis and immune defense. Macrophages engulf foreign invaders and dead cells, release chemicals that recruit other immune cells, and present antigens to T cells. 3. Lymphocytes (B cells and T cells): B cells produce antibodies that recognize and bind to pathogens, while T cells coordinate the immune response (Helper T cells) or directly kill infected or damaged cells (Cytotoxic T cells). 4. Dendritic cells: These specialized immune cells capture, process, and present antigens to T cells in lymph nodes, initiating the adaptive immune response. 5. Natural Killer (NK) cells: NK cells are lymphocytes responsible for recognizing and killing infected or abnormal cells, such as virus-infected or cancerous cells.