An IL-23 antibody is a medication designed to target and neutralize a specific protein in the body called interleukin-23. These antibodies are a type of biologic drug, derived from living organisms, often used in immunology to treat certain conditions by interacting with the immune system.
The Role of IL-23
Interleukin-23 (IL-23) is a cytokine, a type of signaling protein, that plays a role in the body’s immune responses. It is composed of two subunits, p19 and p40, with the p40 subunit also found in interleukin-12 (IL-12). IL-23 is primarily produced by immune cells like macrophages and dendritic cells when they encounter signals, such as those from infections or tissue damage.
IL-23 is particularly involved in promoting inflammation and supporting the development and function of T helper 17 (Th17) cells. Th17 cells are a subset of T cells that produce various inflammatory substances, including IL-17A, IL-17F, IL-6, IL-22, and tumor necrosis factor-alpha (TNF-α). While IL-23 and Th17 cells are involved in protecting the body against certain infections, such as bacterial and fungal pathogens, an overactive IL-23 pathway can lead to chronic inflammation and contribute to autoimmune diseases.
When the IL-23 pathway is dysregulated, it can trigger inflammatory responses that harm the body’s own tissues. This can lead to conditions where the immune system mistakenly attacks healthy cells, contributing to chronic inflammatory and autoimmune diseases.
How IL-23 Antibodies Work
Antibodies are proteins naturally produced by the immune system to identify and neutralize foreign substances, such as bacteria or viruses. In a similar way, IL-23 antibodies are engineered proteins designed to specifically bind to and block the activity of the IL-23 cytokine. These therapeutic antibodies are known as monoclonal antibodies because they are created to recognize a single, specific target.
Most IL-23 antibodies are designed to bind specifically to the p19 subunit of the IL-23 protein. This selective targeting is important because the p19 subunit is unique to IL-23, unlike the p40 subunit which is shared with IL-12. By specifically targeting p19, these antibodies can inhibit IL-23’s activity without affecting IL-12, which helps reduce the risk of unintended side effects.
Once an IL-23 antibody binds to IL-23, it prevents the cytokine from interacting with its receptor on the surface of immune cells, including Th17 cells. This blockade interrupts the inflammatory signaling pathway that is overactive in certain diseases. By preventing IL-23 from activating these cells and promoting inflammation, the antibodies help to reduce the production of pro-inflammatory cytokines like IL-17.
Medical Applications
IL-23 antibodies are used to treat several chronic inflammatory and autoimmune conditions where the IL-23 pathway is overly active. These conditions often involve significant inflammation and can impact various parts of the body.
One prominent application is in moderate to severe plaque psoriasis, a chronic skin condition characterized by red, scaly patches. In psoriasis, the overactivity of the IL-23 pathway leads to an excessive production of inflammatory substances that drive the rapid growth of skin cells. IL-23 antibodies help to reduce this inflammation, leading to significant improvement in skin symptoms for many patients.
IL-23 antibodies are also used for psoriatic arthritis, a related condition that causes joint pain, stiffness, and swelling. The inflammatory mechanisms driven by IL-23 also contribute to joint inflammation and damage in psoriatic arthritis. By targeting IL-23, these antibodies can alleviate joint symptoms and improve physical function.
Another important application is in inflammatory bowel diseases (IBD), such as Crohn’s disease and ulcerative colitis. In these conditions, dysregulated IL-23 activity contributes to chronic inflammation in the gastrointestinal tract. IL-23 antibodies work to reduce this intestinal inflammation, helping to manage symptoms and promote healing in the digestive system.
Receiving Treatment
IL-23 antibody treatments are typically administered through injections. Depending on the specific medication, these can be given as subcutaneous injections (under the skin) or intravenous infusions (into a vein). The frequency of administration varies by medication, but many IL-23 antibody treatments involve less frequent dosing compared to some other biologics.
For example, some IL-23 antibody treatments for plaque psoriasis may involve an initial dose, followed by another dose a few weeks later, and then maintenance doses every 8 to 12 weeks. Patients receiving these treatments require regular monitoring by a healthcare professional to assess their response to the medication and manage any potential considerations.