The immune system defends the body against foreign organisms such as viruses and bacteria. There are several types of cells in the immune system and each one has a specific function. Some are part of the humoral immune system, while others are part of the cellular immune system.
Antibodies are part of the humoral immune system. They bind to bacteria, viruses, and other foreign particles to signal other immune cells to attack them. Antibodies are also known as immunoglobulins.
B lymphocytes, or B Cells, are produced in the bone marrow. They are responsible for the production of antibodies.
T lymphocytes, or T cells, are part of the cellular immune system. There are two types of T cells: cytotoxic T cells and helper T cells. Cytotoxic T cells bind to infected cells through T cell receptors. Helper T cells produce cytokines, which signal B cells and T cells to proliferate. Helper T cells also interact with macrophages.
Macrophages are cells which engulf infected cells or foreign particles through the process of phagocytosis.
Monocytes are a group of white blood cells that differentiate into macrophages.
Neutorphils are cells of the immune system that fights off bacterial and fungal infections. They are another type of white blood cell.
Eosinophils are another group of immune system cells. They are white blood cells that target parasites.
Basophils are white blood cells responsible for allergic responses.
Nelson, David L. Lehninger Principles of Biochemistry 4th ed. W.H. Freeman and Company. 2005