Interleukins are a class of cytokines produced by a variety of cells and acting on a variety of cells. Since it was originally produced by white blood cells and played a role among white blood cells, it is named after it and it is still used. Originally referred to as a cytokine produced by white blood cells and regulating between white blood cells, it now refers to a class of cytokines whose molecular structure and biological functions have been basically defined and have important regulatory roles and are uniformly named, which are the same cytokines as blood cell growth factors. The two coordinate and interact to complete the hematopoietic and immune regulation functions. Interleukins play an important role in transmitting information, activating and regulating immune cells, mediating T, B cell activation, proliferation and differentiation, and in inflammatory responses.

Interleukin is abbreviated as IL, a functionally related expression and regulation of immune responses, which are involved in many factors derived from lymphocytes or macrophages. Lymphocytes derived from lymphocytes, and macrophages are collectively called monokines, in which each factor has different biological activities (eg, macrophage activation, promotion of T cell proliferation, etc.), physical chemistry of the factor itself. The nature is unclear.

During the study of the immune response, many biologically active molecules were found in the mitogen-stimulated cell culture supernatant. The researchers named each of their own measured activities, and reported nearly 100 factors in more than a decade. . Later, comparative studies with molecular biology techniques found that many of the factors named by biological activity in the past were actually the same substance with pleiotropic effects.

Development History

In 1979, in order to avoid the confusion of naming, the 2nd International Lymphokines Symposium named the interleukin-interacting cytokines in the immune response as interleukin (IL), with the Arabic numerals numbered after the name. The differences, such as IL-1, IL-2, ..., are newly named factors. Only the genes that have been cloned and the nature and activity of the products can be recognized by the international conference. These substances have been purified and characterized as a molecule in lymphokines and macroki-ne. The substances initially determined were IL1 and IL2. IL1 belongs to monokine and was previously named after lymphocyte activating factor. Seven kinds of names, such as mitogenic protein and B cell-activating factor, are called. IL2 is a lymphokine, which has been previously called by thymocyte stimulating factor and T cell growth factor.

Human IL-3 was successfully cloned in 1987 and produced recombinant IL-3.
In 1995, the International Federation of Immunology Association officially named IL-16 based on the basic structure and genetic sequence of IL-16.
In 2001, Lee et al first reported the cDNA and amino acid sequences of IL-17E.
As of December 2013, at least 38 members were recognized.


Structure: IL-10 has a molecular weight of 35-40 KD, usually a dimer; it is mainly produced by TH2 cells, and can also be produced by monocytes, keratinocytes and activated B cells.

Function: Major Th2 cells and mononuclear macrophages are produced. It can inhibit the production of pro-inflammatory cytokines; inhibit the expression of MHC class II molecules and B-7 molecules; inhibit the synthesis of cytokines such as IL-2 and IFN-g by T cells; and promote the differentiation and proliferation of B cells.

IL-10 can inhibit the production of cytokines by activated T cells, so it has been called cytokine synthesis inhibitory factor (csif), especially inhibiting the production of IL-2, IFN-γ and lt cytokines by TH1 cells, thereby inhibiting cellular immune responses. . IL-10 can reduce the expression level of MHC class II molecules on the surface of monocyte-macrophages and impair the antigen-presenting ability of APC, which may actually be the reason for its inhibition of cell-mediated immunity. In addition, IL-10 can also inhibit NK cell activity, interfere with NK cells and macrophages to produce cytokines; but it can stimulate B cell differentiation and proliferation, and promote antibody production.


Structure: IL-12 is mainly produced by B cells and macrophages; its molecule is a heterodimer, and two subunits of 40KD (p40) and 35KD (p35) are linked by a disulfide bond.

Function: IL-12 mainly acts on T cells and NK cells and has been named as cytotoxic lymphocyte maturation factor (CLMF) and NK cell stimulating factor (NKsf). IL-12 can stimulate the proliferation of activated T cells, promote the differentiation of TH0 cells into TH1 cells; induce the cytotoxic activity of ctl and NK cells and promote their secretion of cytokines such as IFN-γ, TNF-α, GM-CSF; The expression of cells and IL-2rα, TNF receptor and CD56 molecules enhances the adcc effect on tumor cells.


Function: IL-17 is the main effector of Th17 cells, secreted by CD4+ T cells, capable of inducing the synthesis and secretion of IL-6, IL-8, G-CSF and PGE2 by epithelial cells, endothelial cells and fibroblasts, and promoting ICAM-1 expression.

The study found that IL-17 is a T cell-derived cytokine that includes six member ligands (IL-17A~IL-17F) and five receptors (IL-17RA~IL-17RD and SEF). IL-17 is a proinflammatory cytokine mainly produced by activated T cells, which can promote the activation of T cells and stimulate the production of various cytokines such as IL-6 and IL-8 by epithelial cells, endothelial cells and fibroblasts. Granulocyte-macrophage stimulating factor (GM-CSF) and chemical stimulating hormone 1 and cellular adhesion molecule 1 (CAM-1), which leads to inflammation.

IL-17 is an early promoter of T cell-induced inflammatory responses that amplify the inflammatory response by promoting the release of pro-inflammatory cytokines. After binding to the receptor, IL-17 exerts its biological effects through the MAP kinase pathway and the nuclear factor kB (NF-kB) pathway. Th17 cells secrete IL-17A, IL-17F, IL-6 and tumor necrosis factora (TNF-a), which can collectively mobilize, recruit and activate neutrophils. IL-17 produced by Th17 cells can effectively mediate the excitatory process of neutrophil mobilization, thereby effectively mediating the inflammatory response of tissues.

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