Subunit beta of interleukin 12 (also known as IL-12B, natural killer cell stimulatory factor 2, cytotoxic lymphocyte maturation factor p40, or interleukin-12 subunit p40) is a

protein subunit In structural biology, a protein subunit is a polypeptide chain or single protein molecule that assembles (or "''coassembles''") with others to form a protein complex. Large assemblies of proteins such as viruses often use a small number of t ...

that in humans is encoded by the IL12B

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

. IL-12B is a common subunit of

interleukin 12 Interleukin 12 (IL-12) is an interleukin that is naturally produced by dendritic cells, macrophages, neutrophils, helper T cells and human B-lymphoblast, lymphoblastoid cells (NC-37) in response to antigenic stimulation. IL-12 belongs to the ...

and interleukin 23.

Function

This gene encodes a subunit of

, a

cytokine Cytokines () are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are produced by a broad range of cells, including immune cells like macrophages, B cell, B lymphocytes, T cell, T lymphocytes ...

that acts on T and

natural killer cell Natural killer cells, also known as NK cells, are a type of cytotoxic lymphocyte critical to the innate immune system. They are a kind of large granular lymphocytes (LGL), and belong to the rapidly expanding family of known innate lymphoid cells ...

s, and has a broad array of biological activities. Interleukin 12 is a disulfide-linked heterodimer composed of the 40 kDa

cytokine receptor Cytokine receptors are receptors that bind to cytokines. In recent years, the cytokine receptors have come to demand the attention of more investigators than cytokines themselves, partly because of their remarkable characteristics, and partly be ...

like subunit encoded by this gene, and a 35 kDa subunit encoded by ''

IL12A Interleukin-12 subunit alpha (IL-12 p35) is a protein that in humans is encoded by the ''IL12A'' gene. Function This gene encodes a subunit of the cytokine Interleukin 12 (IL-12) that acts on T cell, T and natural killer cells, and has a broad ...

''. This cytokine is expressed by activated

macrophages Macrophages (; abbreviated MPhi, φ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that ...

that serve as an essential inducer of

Th1 cell The T helper cells (Th cells), also known as CD4+ cells or CD4-positive cells, are a type of T cell that play an important role in the adaptive immune system. They aid the activity of other immune cells by releasing cytokines. They are considere ...

s development. This cytokine has been found to be important for sustaining a sufficient number of memory/effector Th1 cells to mediate long-term protection to an intracellular pathogen. Overexpression of this gene was observed in the central nervous system of patients with

multiple sclerosis Multiple sclerosis (MS) is an autoimmune disease resulting in damage to myelinthe insulating covers of nerve cellsin the brain and spinal cord. As a demyelinating disease, MS disrupts the nervous system's ability to Action potential, transmit ...

(MS), suggesting a role of this cytokine in the pathogenesis of the disease. The promoter polymorphism of this gene has been reported to be associated with the severity of atopic and non-atopic

asthma Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...

in children.

Role as IL-23 subunit

Interleukin-12 p40 also serves as a subunit of interleukin 23.

Function

Role as IL-23 subunit

References

Further reading