The immune system has several parts, called immunoglobulins. Each of these immunoglobulins binds to an antigen called an antigen. Unlike antibodies, however, which are made up of one specific antigen, T cells have many differences. The main difference between Ab and Ig is the type of antigen they are designed to recognize. Hence, these antibodies have a broader range of antigen-binding sites than their opposites.
The lymph nodes are small bean-shaped tissues located along the lymphatic vessels. They act as filters, trapping germs and activate the production of special antibodies in the blood. Swollen lymph nodes are a sign of active immune system. As these lymph nodes are filled with immune system cells, they circulate through the blood and move on to other organs. These lymph nodes also contain white blood cells, known as phagocytes. Meanwhile, the spleen breaks down red blood cells and erythrocytes, while the tonsils store platelets.
Leukocytes are white blood cells that travel throughout the body. They can engulf bacteria or viruses. Another type of white blood cell is called a macrophage. This type of cell has the ability to travel outside of the bloodstream, and releases cytokines to warn other immune cells about the presence of pathogens. Other parts of the immune system include mast cells and dendritic cells. These cells act as messengers to other immune system cells and kill bacteria and other organisms.