Difference Between Interleukin 1 and 2

The key difference between interleukin 1 and 2 is that interleukin 1 is a cytokine which is primarily responsible for the regulation of acute and chronic inflammation while interleukin 2 is a cytokine which is primarily responsible for growth and differentiation of T cells.

Interleukins are a type of cytokines produced by a wide variety of body cells. They are proteins secreted in response to pathogens and other antigens. There are more than 50 interleukins and related proteins coded by the human genome. They have the ability to bind with cell receptors found on the surface. Interleukins play a primary role in activating and differentiating immune cells. Moreover, they have pro and anti-inflammatory properties. Therefore, they are an important part of the inflammatory response of the body against infections. Interleukin 1 and 2 are two major families of interleukins. They are mainly responsible for activating T and B lymphocytes.

CONTENTS

1. Overview and Key Difference
2. What is Interleukin 1 
3. What is Interleukin 2
4. Similarities Between Interleukin 1 and 2
5. Side by Side Comparison – Interleukin 1 vs 2 in Tabular Form
6. Summary

What is Interleukin 1?

Interleukin 1 family (IL-1) is a group of 11 cytokines. There are two most studied members of interleukin1. They are interleukin 1 alpha and interleukin 1 beta (IL1 alpha and IL1 beta). They bind with same the receptor: type I IL-1 receptor (IL-1RI). Both IL-1α and IL-1β show a strong pro-inflammatory effect. Different cells, including macrophages, large granular lymphocytes, B cells, endothelium, fibroblasts, and astrocytes secrete IL-1.

The principal targets of IL-1 are T cells, B cells, macrophages, fibroblasts, dendritic cells, endothelial and tissue cells. The major functions of IL-1 are lymphocyte activation, macrophage stimulation, increased leukocyte/endothelial adhesion, fever due to hypothalamus stimulation, the release of acute-phase proteins by the liver, apoptosis in many cell types and cachexia.

What is Interleukin 2?

Interleukin 2 (IL-2) is a cytokine signalling molecule made by activated T cells. Structurally, it is a 15.5–16 kDa protein that binds with IL-2 receptors on lymphocytes.  IL-2 mainly regulates the activities of white blood cells mediating interactions between the cells. The main target of IL-2 is T cells and IL-2 is necessary for growth, proliferation, and differentiation of naïve T cells into effector T cells. Therefore, IL-2 was first defined as a T cell growth factor.

The main functions of IL-2 are T-cell proliferation and differentiation, increased cytokine synthesis, potentiating Fas-mediated apoptosis, and promoting regulatory T cell development. Moreover, it affects the proliferation and activation of natural killer cells and B-cell proliferation and antibody synthesis. Furthermore, IL-2 stimulates the activation of cytotoxic lymphocytes and macrophages. IL-2 is most studied for cancer treatments. It has been used in treatments of metastatic renal cell carcinoma and metastatic melanoma. IL-2 has been used in combination therapy often with interferons.

What are the Similarities Between Interleukin 1 and 2?

• Interleukin 1 and 2 are cytokine signalling molecules in the immune system.
• Therefore, they are responsible for immunity.
• Both are proteins.
• They bind with specific cell surface receptors.

What is the Difference Between Interleukin 1 and 2?

Interleukin 1 is a family of interleukin that comprises of 11 cytokines responsible for the regulation of inflammation. Interleukin 2 is a cytokine signalling molecule which promotes further growth and differentiation of activated T cells. So, this is the key difference between interleukin 1 and 2. Also, IL-1 binds with IL-1 receptors while IL-2 binds with IL-2 receptors. Moreover, macrophages, large granular lymphocytes, B cells, endothelium, fibroblasts, and astrocytes secrete IL-1 while T cells secrete IL-2.

Below info-graphic lists the differences between interleukin 1 and 2 in tabular form.

Summary – Interleukin 1 vs 2

Interleukin 1 and 2 are the most studied members of cytokines. Interleukin 1 is a family of cytokines that has a strong pro-inflammatory effect. Therefore, IL-1 is primarily responsible for the regulation of acute and chronic inflammation. Interleukin 2 is a cytokine signalling molecule produced by activated T cells. IL-2 promotes further growth and differentiation of activated T cells. Both IL-1 and IL-2 are responsible for innate and adaptive immunity. They play key roles in fighting cancer, infectious disease and other diseases. Thus, this summarizes the difference between interleukin 1 and 2.

Reference:

1. Vaillant, Angel A. Justiz. “Interleukin.” StatPearls [Internet]., U.S. National Library of Medicine, 30 Aug. 2020, Available here.
2. Jiang, Tao, et al. “Role of IL-2 in Cancer Immunotherapy.” Oncoimmunology, Taylor & Francis, 25 Apr. 2016, Available here.

Image Courtesy:

1. “2ILA” By Boghog2 (talk) – Own work (Original text: self-made) (Public Domain) via Commons Wikimedia
2. “IL2 Crystal Structure” By Ramin Herati – Created from PDB 1M47 and rendered by me using Pymol (Public Domain) via Commons Wikimedia