A mitogen is a chemical substance

Chemical substance

In chemistry, a chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components by physical separation methods, i.e. without breaking chemical bonds. They can be solids, liquids or gases.Chemical substances are...

 that encourages a cell to commence cell division

Cell division

Cell division is the process by which a parent cell divides into two or more daughter cells . Cell division is usually a small segment of a larger cell cycle. This type of cell division in eukaryotes is known as mitosis, and leaves the daughter cell capable of dividing again. The corresponding sort...

, triggering mitosis

Mitosis

Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly...

. A mitogen is usually some form of a protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

.

Mitogenesis is the induction (triggering) of mitosis, typically via a mitogen.

Mitogens trigger signal transduction

Signal transduction

Signal transduction occurs when an extracellular signaling molecule activates a cell surface receptor. In turn, this receptor alters intracellular molecules creating a response...

 pathways in which mitogen-activated protein kinase

Mitogen-activated protein kinase

Mitogen-activated protein kinases are serine/threonine-specific protein kinases that respond to extracellular stimuli and regulate various cellular activities, such as gene expression, mitosis, differentiation, proliferation, and cell survival/apoptosis.-Activation:MAP kinases are activated...

 is involved, leading to mitosis.

Use in immunology

B cell

B cell

B cells are lymphocytes that play a large role in the humoral immune response . The principal functions of B cells are to make antibodies against antigens, perform the role of antigen-presenting cells and eventually develop into memory B cells after activation by antigen interaction...

s can enter mitosis when they encounter an antigen

Antigen

An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader. These invaders can be molecules such as...

 matching their immunoglobulin

Antibody

An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...

.

Mitogens are often used to stimulate lymphocyte

Lymphocyte

A lymphocyte is a type of white blood cell in the vertebrate immune system.Under the microscope, lymphocytes can be divided into large lymphocytes and small lymphocytes. Large granular lymphocytes include natural killer cells...

s and therefore assess immune function.

The most commonly used mitogens in clinical laboratory medicine are:

Name

Acts upon T cell T cell T cells or T lymphocytes belong to a group of white blood cells known as lymphocytes, and play a central role in cell-mediated immunity. They can be distinguished from other lymphocytes, such as B cells and natural killer cells , by the presence of a T cell receptor on the cell surface. They are... s?

Acts upon B cell B cell B cells are lymphocytes that play a large role in the humoral immune response . The principal functions of B cells are to make antibodies against antigens, perform the role of antigen-presenting cells and eventually develop into memory B cells after activation by antigen interaction... s? >- | phytohaemagglutinin Phytohaemagglutinin Phytohaemagglutinin is a lectin found in plants, especially legumes. PHA actually consists of two closely related proteins, called leucoagglutinin and PHA-E. The letters E and L indicate these proteins agglutinate Erythrocytes and Leukocytes...  (PHA)

yes

>- | concanavalin A Concanavalin A Concanavalin A is a lectin originally extracted from the jack-bean, Canavalia ensiformis. It binds specifically to certain structures found in various sugars, glycoproteins, and glycolipids, mainly internal and nonreducing terminal α-D-mannosyl and α-D-glucosyl groups...  (conA)

yes

>- | lipopolysaccharide Lipopolysaccharide Lipopolysaccharides , also known as lipoglycans, are large molecules consisting of a lipid and a polysaccharide joined by a covalent bond; they are found in the outer membrane of Gram-negative bacteria, act as endotoxins and elicit strong immune responses in animals.-Functions:LPS is the major...  (LPS)

no

>- | pokeweed mitogen Pokeweed mitogen Pokeweed mitogen is a mitogen derived from Phytolacca americana. It functions as a lectin....  (PWM)

yes

yes

Lipopolysaccharide

Lipopolysaccharide

Lipopolysaccharides , also known as lipoglycans, are large molecules consisting of a lipid and a polysaccharide joined by a covalent bond; they are found in the outer membrane of Gram-negative bacteria, act as endotoxins and elicit strong immune responses in animals.-Functions:LPS is the major...

 toxin

Toxin

A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...

 from gram-negative bacteria is thymus

Thymus

The thymus is a specialized organ of the immune system. The thymus produces and "educates" T-lymphocytes , which are critical cells of the adaptive immune system....

-independent. They may directly activate B cells, regardless of their antigen

Antigen

An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader. These invaders can be molecules such as...

ic specificity.

Plasma cell

Plasma cell

Plasma cells, also called plasma B cells, plasmocytes, and effector B cells, are white blood cells which produce large volumes of antibodies. They are transported by the blood plasma and the lymphatic system...

s are terminally differentiated

Cellular differentiation

In developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. Differentiation occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of...

 and, therefore, cannot undergo mitosis. Memory B cell

Memory B cell

Memory B cells are a B cell sub-type that are formed following primary infection.-Primary response, paratopes, and epitopes:In wake of first infection involving a particular antigen, the responding naïve cells proliferate to produce a colony of cells, most of which differentiate into the plasma...

s can proliferate to produce more memory cells or plasma B cells. This is how the mitogen works, that is, by inducing mitosis in memory B cells to cause them to divide, with some becoming plasma cells.

Mitogens in human physiology

Insulin-like Growth Factor 1

Insulin-like growth factor 1

Insulin-like growth factor 1 also known as somatomedin C is a protein that in humans is encoded by the IGF1 gene. IGF-1 has also been referred to as a "sulfation factor" and its effects were termed "nonsuppressible insulin-like activity" in the 1970s.IGF-1 is a hormone similar in molecular...

 mediates the major growth-promoting effect of Human Growth Hormone as a paracrine agent at growth plates in the skeletal system.