INTERLEUKINS & THEIR ROLE

VIPIN MOHAN2011-09-112College of AgricultureVellayani, TVM

• Interleukins are a group of cytokines (secreted proteins andsignaling molecules) that were first seen to be expressed by white blood cells (leukocytes).

• the term was coined by Dr Vern Paetkau, University of Victoria in 1979

• The term interleukin derives from (inter-) "as a means of communication", and (-leukin) "deriving from the fact that many of these proteins are produced by leukocytes and act on leukocytes".

• The function of the immune system depends in a large part on interleukins.

•  rare deficiencies of a number of them have been described, all featuring autoimmune diseases or immune deficiency.

• The majority of interleukins are synthesized by helperCD4  T lymphocytes, as well as through monocytes, macrophages, and endothelial cells.

• They promote the development and differentiation of T and  B lymphocytes,and hematopoietic cells.

Common families of interleukins

–  Interleukin 1–  Interleukin 2–  Interleukin 3–  Interleukin 4–  Interleukin 5–  Interleukin 6– Interleukins 7 and 9–  Interleukin 8–  Interleukin 10–  Interleukin 11–  Interleukin 12–  Interleukin 13–  Interleukin 15–  Interleukin 17–  Interleukin 18–  Interleukin 23

• Interleukin 1 alpha and interleukin 1 beta (IL-1 alpha and IL-1 beta) are cytokines that participate in the regulation of immune responses, inflammatory reactions, and hematopoiesis

• Interleukin 1 also plays a role in the Central Nervous System.

Interleukin 1

Produced by activated Macrophages,  Endothelia Cells, B-Cells, andFibroblast Cells.

L-1 also augments CorticoSteroid release, induces fever and shivering - useful responses, because elevated body temperature reduces Bacterial growth.

Interleukin 2

• T Lymphocytes regulate the growth and differentiation of T cells and certain B cells through the release of secreted protein factors.

• These factors, which includeinterleukin 2 (IL2), are secreted by lectin- or antigen-stimulated T cells, and have various physiological effects.

• IL2 is a lymphokine that induces the proliferation of responsive T cells.

• In addition, it acts on some B cells, via receptor-specific binding, as a growth factor and antibody production stimulant. .

Interleukin 3

• Interleukin 3 (IL3) is a cytokine that regulates blood-cell production by controlling the production, differentiation and function of granulocytes and macrophages.

•  The protein, which exists in vivo as a monomer, is produced in activated T cells and mast cells,and is activated by the cleavage of an N-terminal signal sequence.

INTERLEUKIN 4

• Interleukin 4 (IL4) is produced by CD4 T cells specialized in providing help to B cells to proliferate and to undergo class switch recombination and somatic hypermutation.

• Stimulates production of AntiBody-producing B-Cells, leading to the production of IgG & IgE.

• IL-4 also promotes CD8+ Cell growth and promotes  TH2  Cell differention.

Interleukin 5

• Interleukin 5 (IL5), also known as eosinophil differentiation factor (EDF), is a lineage-specific cytokine for eosinophilpoiesis.

• It regulates eosinophil growth and activation,and thus plays an important role in diseases associated with increased levels of eosinophils, including asthma.

Interleukin 6

• Interleukin 6 (IL6), also referred to as B-cell stimulatory factor-2 (BSF-2) and interferon beta-2, is a cytokine involved in a wide variety of biological functions.

•  It plays an essential role in the final differentiation of B cells into IG-secreting cells, nerve cell differentiation, and, in hepatocytes.

• Is produced by many cell types, including T-Cells, Macrophages, B-Cells, Fibroblasts, and Endothelia Cells.

• IL-6 stimulates several types of Leukocytes, and the production of Acute Phase Proteins in the Liver.

• IL-6 is particularly important in inducing B-Cells to differentiate into AntiBody Forming Cells (Plasma Cells).

Interleukin 7

• InterLeukin-7 (IL-7)• Is made by Bone Marrow Stroma Cells

and acts on Thymocytes.• IL-7 is a T-Cell growth and activation

factor, and a Macrophage Activation Factor.

• Interleukin 7 (IL-7) is a cytokine that serves as a growth factor for early lymphoid cells of both B- and T-cell lineages.

Interleukin 8

• InterLeukin-8 (IL-8)• Is produced by most cells of the body,

especially Macrophages andEndothelia Cells.

• IL-8 enhances Inflammation, by enabling Immune Cells to migrate into tissue, & is a powerful inducer of Chemotaxis for Neutrophil Cells.

Interleukin 9

• InterLeukin-9 (IL-9)• Up-regulates Th1 responses (Enhancing

Inflammation) by inhibiting T-Cell Apoptosis.

•  Interleukin 9(IL-9) is a cytokine that supports IL-2 independent and IL-4 independent growth of helper T cells.

• Interleukin 7 and 9 seems to be evolutionary related.

Interleukin 10

• Interleukin 10 (IL-10) is a protein that inhibits the synthesis of a number of cytokines, including IFN-gamma, IL-2, IL-3, TNF, and GM-CSF produced by activated macrophages and by helper T cells.

• TNF-. IL-10 is also very important in B-Cell activation

• Interleukin 11 (IL-11) is a secreted protein that stimulates megakaryocytopoiesis, resulting in increased production of platelets, as well as activating osteoclasts, inhibiting epithelial cell proliferation and apoptosis, and inhibiting macrophage mediator production.

• These functions may be particularly important in mediating the hematopoietic, osseous and mucosal protective effects of interleukin 11.

•  Family members seem to be restricted to mammals.

Interleukin 11

Interleukin 12

• Interleukin 12 (IL-12) is a disulphide-bonded heterodimer consisting of a 35kDa alpha subunit and a 40kDa beta subunit.

• It is involved in the stimulation and maintenance of Th1 cellular immune responses, including the normal host defence against various intracellular pathogens, such as Leishmania, Toxoplasma, Measles virus, andHuman immunodeficiency virus 1 (HIV).

• IL-12 also has an important role in pathological Th1 responses, such as in inflammatory bowel disease and multiple sclerosis.

Interleukin 13

• Interleukin 13 (IL-13) is a pleiotropic cytokine that may be important in the regulation of the inflammatory and immune responses.

• It inhibits production of Macrophage Inflamatory Cytokines.

• with IL-2 in regulating interferon-gamma synthesis.

Interleukin 15

• Interleukin 15 (IL-15) is a cytokine that possesses a variety of biological functions, including stimulation and maintenance of cellular immune responses.

• Shares several biological activities with IL-2 and is produced by both Epithelial Cells and Monocytes.

• IL-15 also induces T-Cellproliferation, enhances NK Cell CytoToxicity and stimulates B-Cells to proliferate and secrete ImmunoGlobulins.

Interleukin 17

• Interleukin 17 (IL-17) is a potent proinflammatory cytokine produced by activated memory T cells.

•  The IL-17 family is thought to represent a distinct signalling system that appears to have been highly conserved across vertebrate evolution.

Interleukin 18

• InterLeukin-18 (IL-18)• Induces Interferon-gamma (IFN-)

production.

Interleukin 23

• InterLeukin-23 (IL-23)• One of the essential factors

required for the expansion of pathogenic CD4+ T-Cells, which is characterized by the production of IL-17, IL-6, and Tumor Necrosis Factor

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