Interleukin-2 (IL-2) is a key molecule in the immune system. It has been found to regulate the function of T cells and is essential for fighting off chronic infections of infectious agents such as influenza and HIV. IL-2 has also been found to be crucial for suppressing autoimmune diseases such as lupus and MS. There are several resources online where you can learn more about interleukin-2.
The Role of in Regulating Immune Responses
Interleukin 2 is an important molecule that regulates immune response in both homeostasis and activation phases. The first function of interleukin-2 in the immune system is to regulate the differentiation of naïve T cells into effector T cells. Effector T cells are important for combating infections and diseases. Therefore, it is a key molecule in activating the immune system against parasites, viruses, and bacteria.
IL-2 also induces the proliferation of a subset of regulatory t cells that restrain the immune system. Next, IL-2 signals other cytokines to induce the proliferation of helper t cells. The cytokines that are induced include IL-4, IL-5, and IL-13. In addition to inducing other cytokines to induce proliferation of helper t cells, interleukin 2 also activates NK T cells.
Other Functions of Interleukin-2
Interleukin-2 has many other functions such as increasing the phagocytic activity of macrophages and inducing the differentiation of Th17 cells.
Although interleukin-2 is a key molecule in activating the immune system, it is also naturally occurring in the body.
Elevated levels of interleukin-2 are produced in the body during active immune responses. IL-2 is also naturally occurring in tumors. This is because it’s a key molecule in preventing an overactive immune response against cancerous cells.
Suppressor of Autoimmune Diseases
Interleukin 2 is an inducer of immune response and a suppressor of autoimmune disease. It activates CD4+ T-cells and CD8+ T-cells in order to activate the immune system. It has also been found that IL -2 is produced by the body in response to most autoimmune diseases such as rheumatoid arthritis, lupus, multiple sclerosis, and Crohn’s disease.
IL-2 takes part in suppressing immune responses in autoimmune diseases by inducing regulatory T cells while suppressing Th1 cells such as cytotoxic T cells. It also regulates the synthesis of IL-10 and TGF-β, thus suppressing inflammation and promoting a regulatory environment.
Regulating Production in the Brain
Interleukin-2 is present in the central nervous system (CNS) of uninfected individuals. Its presence is especially prominent in gray matter, where it is found at levels that are double those found in white matter zones. It is believed to have certain functions related to neural repair and plasticity in the CNS.
It has been found that interleukin-2 is a neurotrophin and has the ability to regulate its production in the brain. This is due to its ability to induce the proliferation of neural stem cells, which are responsible for maintaining white matter structures and producing new neurons.
Both interleukin-2 and interferon-gamma have been found to have a protective effect against damage caused by advanced glycation end products (AGEs) on cell membranes. The mechanism for how these molecules protect against AGEs is by promoting protein cross-talk between certain immune cells and neurons, which leads to clearance of AGEs. This is similar to another molecule called beta-amyloid- plasmin endopeptidase.
IL-2 and Cognitive Impairment
For those with mild cognitive impairment (MCI), IL-2 has been shown to significantly improve verbal memory, global cognition, and executive function in clinical trials. However, a small percentage of patients might be completely resistant to IL-2, which means improvements may not be seen in some patients.
The mechanism by which IL-2 improves mild cognitive impairment (MCI) is not fully understood. One theory involves the production of anti-inflammatory molecules in the brain, called cytokines. IL-2 can also act to increase the number of synapses in the brain. Synapses are where cells communicate with each other and are compromised in Alzheimer’s disease.
Interleukin-2 has also been found to play a role in axon guidance. Neural precursor cells are required for the completion of neuronal development and the creation of new connections. These cells are also central to neural plasticity and learning. Interleukin-2 has been found to activate neural progenitor cells by inducing proliferation and inducing axon guidance pathways.
Interleukin 2 can be found at significantly higher levels in the brain in patients with multiple sclerosis (MS). This increased expression is not due to an infectious agent. The structure of IL-2 is similar to that of myelin basic protein (MBP).