What are interleukins?
Interleukins are a kind of large group of cytokine protein molecules that play a vital role in stimulating an immune response to a pathogenic antigen. They also help in regulating cell growth, differentiation, proliferation, maturation, activation and motility of immune cells.
Discovery and definition of Interleukin
Interleukins were discovered in the year 1970. Initially, it was thought that interleukins were produced by leukocytes(white blood cells), and as such, these molecules were named interleukins, which defines the meaning of the word as “between leukocytes”. But through later observations, it was found out that interleukins were also produced by various cells of the body.
- Interleukin production is a transitory process. Most of the interleukins are encoded by an unstable mRNA(messenger RNA) which results in an ephemeral synthesis of these molecules. Once synthesized, these molecules are briskly released.
- These interleukins then migrate to a particular target cell with the aid of a receptor molecule that binds to the surface of that cell.
- As a result, a cascade of signals is set off within the target cell that eventually transmutes the action of the target cell.
- Oftentimes, interleukins have a great impact on the synthesis and activation of other interleukins. For example, the lymphocytic activation promoted by IL-1 influences the release of IL-2.
Interleukin in humans and its function
Interleukins observed in human diseases are:
To induce fever, IL-1 acts as an endogenous pyrogen and stimulates the hypothalamus.
- T-cell hyperactivation and T cell-mediated autoimmune responses are induced when IL-2 is experimentally inhibited.
- IL-2 is also used in the immunotherapy of melanoma and renal carcinoma.
Inhibition of IL-10 hyper activates the macrophages which leads to the development of an inflammatory bowel disease.
Through its anti-inflammatory effects, IL-27 isknown to suppress autoimmune reactions.
IL-29 is used as a biomarker of joint inflammation in patients with osteoarthritis.
Increased levels of IL-36 can be seen in human psoriasis.
Different types of interleukin and its functions
- Interleukins are known to exhibit both autocrine and paracrine functions. These molecules are used in animal studies to carry out systemic inquiry pertaining to clinical medicine.
- First interleukin, interleukin-1(IL-1) was discovered in 1977. As many as 40 ILs(Interleukins) are known today. Each IL shows distinct cellular function and its production may not be confined to only one kind of cell.