The bone marrow inside of your bones contain special cells that fight viruses. These cells are known as white blood cells and are the main components of the immune system.
The spleen acts as a filter for blood. Old red blood cells are recycled here. The spleen also helps fight certain kinds of bacteria that cause pneumonea and meningitis.
The main function of the thymus gland is to produce and process
T-cells In children.It even produces some white blood cells.
Lymph nodes are all around the body and act as filters or traps for foregin particles. They are packed tightly with white blood cells.