According to the different primary structure of interferon protein, it is divided into three types of α, β and γ. Interferon gamma (IFN-γ) is produced by immune lymphocytes. The gene structure contains introns and plays an important role in the adaptive immune response. IFN-γ is a multipotent cytokine that can promote macrophage activation, mediate antiviral and antibacterial immune responses, enhance antigen presentation, activate the innate immune system, coordinate the interaction of lymphocytes and endothelial cells, regulate the balance between Th1 and Th2 cells and regulate cell proliferation and apoptosis. In the adaptive immune response, IFN-γ is produced by CD4+ helper T cells (Th1) and CD8+ cytotoxic T cells (CTL) when stimulated by antigens presented by the major histocompatibility complex (MHC). In the innate immune response, IFN-γ is produced when natural killer cells (NK cells) are stimulated by interleukin 12 (IL-12) and interleukin 18 (IL-18).
IFN-γ is secreted by the cells of the immune system, and has the functions of regulating immune response, cell proliferation or apoptosis. IFN-γ regulates the immune response by activating signaling pathways. IFN-γ binds to the interferon-gamma receptor（IFNGR）to cause dimerization of the receptor. Two IFNGR1 chains are combined with one IFN-γ dimer, and then they are combined with two IFNGR2 chains. The complex induces conformational changes and causes JAK1 and JAK2 to undergo phosphorylation and activation, which makes STAT1 phosphorylate. Phosphorylated STATA1 assembles into a dimer and entry into the nucleus. The STAT1 dimer binds to gamma activated sequence (GAS) to initiate transcription of the downstream target gene, thereby activating the cellular immune response. In addition to the JAK-STAT1 pathway, IFN-γ can also activate the MAP kinase pathway, the PI3-K pathway, the Raf-MEK-MAPK pathway, and the nuclear factor kappa-B (NF-κB) pathway linked via MyD88.
One of the factors affecting IFN-γ regulation of cell proliferation or apoptosis is the IFN-γ receptor. The IFN-γ receptor is composed of a ligand-binding chain IFNGR1 and a signaling chain also called a helper chain IFNGR2. IFNGR2 is usually a decisive factor for IFN-γ-induced cellular responses, and its expression may be strictly regulated by the state of the cell, while IFNGR1 is relatively excessive. The content of IFNGR2 on the cell surface determines the response induced by IFN-γ. A high level of IFNGR2 can quickly induce the activation of signal transduction and the activation of transcription activator STAT1 and the large expression of interferon regulatory factor IRF1, which then stimulates cell apoptosis. In contrast, low levels of IFNGR2 can only slowly induce the activation of STAT1, and the expression of IRF1 is also low, thereby inducing cell proliferation. Therefore, the amount of IFNGR2 expression on the cell surface determines whether IFN-γ induces apoptosis or cell proliferation. This mechanism facilitates the phenotype conversion between Th1 cells and Th2 cells, and is beneficial to the balance of cell numbers between Th1 cells and Th2 cells.
Fig 1. Mechanism of Signaling
Creative Proteomics can provide cytokine detection platform for scientific research. According to different purposes, our dedicated analysts will customize exclusive solutions for you. We aim to provide customers with high-quality and convenient services to help you accelerate the progress of your project.
We mainly provide the Luminex cytokine detection platform. Luminex uses fluorescently encoded microspheres with specific antibodies to different target molecules. The different microspheres can be combined freely to a certain extent so that up to 100 analytes can be tested multiple times simultaneously in a single experiment.
The Luminex cytokine assay platform has the following advantages:
For your different needs, we can also provide the following detection methods:
For more information about the IFN detection service or need other detection requirements, please contact us.