* White blood cells (WBCs): These are the main players in the immune system. They are divided into different types, each with a specific function.
* Neutrophils: These are the most abundant WBCs and act as the first line of defense against bacteria and fungi. They engulf and destroy these invaders through a process called phagocytosis.
* Macrophages: These cells are also phagocytic and engulf bacteria, viruses, and dead cells. They also play a role in presenting antigens to other immune cells, initiating an immune response.
* Natural killer (NK) cells: These cells are part of the innate immune system and can directly kill infected or cancerous cells without prior sensitization.
* Lymphocytes: These cells are part of the adaptive immune system and are responsible for recognizing specific antigens and mounting a targeted immune response. They include:
* B cells: These cells produce antibodies that bind to specific antigens and help eliminate invaders.
* T cells: These cells directly attack infected cells or cancer cells, or they help regulate the immune response.
Other immune system components also play a role:
* Antibodies: These proteins are produced by B cells and bind to specific antigens, helping to neutralize or eliminate them.
* Complement system: This is a cascade of proteins that helps destroy bacteria, viruses, and other pathogens.
It's important to note that all of these cells and components work together in a complex and coordinated way to protect the body from infection and disease.
