interferonok

Interferonok, or interferons, are a family of signaling proteins produced by host cells in response to viruses and other immune challenges. They are cytokines that help coordinate innate and adaptive immune responses, restricting viral replication and modulating immune cell activity. They were discovered in 1957 by Isaacs and Lindenmann as substances that interfere with viral spread, hence the name.

There are three main types of interferons in humans: Type I (including IFN-α, IFN-β, and IFN-ω), Type II (IFN-γ), and Type III (IFN-λ). Type I and Type III interferons are produced by a variety of cells after viral recognition and signal through distinct receptor complexes (IFNAR1/2 for Type I and IFNLR1/IL10R2 for Type III). Type II interferon is produced mainly by activated T cells and natural killer cells and signals through the IFN-γ receptor (IFNGR1/2). The binding of interferons to their receptors activates the JAK-STAT pathway, leading to transcription of interferon-stimulated genes that establish an antiviral state, enhance antigen presentation via MHC class I, and modulate the activity of dendritic cells, NK cells, and T cells.

Clinically, interferons have been used as therapies for several conditions. Interferon-β is approved for multiple sclerosis to reduce relapses. Interferon-α has been used for certain hematologic cancers (such as hairy cell leukemia and renal cell carcinoma) and some viral infections historically, including chronic hepatitis B and C (though direct-acting antivirals have largely supplanted this use). Adverse effects are common and include flu-like symptoms, fatigue, cytopenias, and potential neuropsychiatric effects; treatment can be limited by the development of neutralizing antibodies. Interferons are produced recombinantly for medical use and delivered by subcutaneous, intramuscular, or intravenous routes, with pegylated forms extending half-life in some indications.