Good news for the interferon domain this week with the launch of a new kit: the Verikine Human Interferon Gamma Receptor 1 (IFNGR1) ELISA Kit. This immunoassay provides researchers with a high quality product and excellent data reproducibility for this area.
For humans, IFN-α consists of a group of proteins that are greater than 85% homologous by amino acid sequence. A lot of individual human IFN-α subtypes have been identified and many have different properties. For the moment, we don’t know exactly why there are multiple IFN-α subtypes. A variety of studies suggested they possess overlapping but also unique sets of biological activities. Quantification of IFN is essential but usually methods don’t take account all IFN types. In this post, I would like to focus on a relevant ELISA kit to avoid this problem.
Interferons (IFNs) are low molecular weight proteins that belong to the class of glycoproteins known as cytokines. IFNs are part of the non-specific immune system and are an important first line of defense against viral infections. They are released by host cells in response to the presence of pathogens such as viruses, bacteria, parasites or tumor cells.
IFNs have other functions as well: they activate immune cells, such as natural killer cells and macrophages; they increase recognition of infection or tumor cells by up-regulating antigen presentation to T lymphocytes; and they increase the ability of uninfected host cells to resist new infection by virus. Host symptoms, such as aching muscles and fever, are related to the production of IFNs during infection. [Read more…]
ISG15 ubiquitin-like modifier (ISG15) functions intracellularly as a Ubiquitin homologue and a cytokine. ISG15 induces production of IFN-gamma and augments NK/lymphokine-activated killer cell proliferation and function. Secreted from monocytes and lymphocytes, low levels of ISG15 are present constitutively in PBMCs. Interestingly, a dose-dependent ISG15 synthesis has been observed in response to IFN-alpha or IFN-beta, but not IFN-gamma.
For instance, ISG15 is secreted in response to IFN-beta treatment in vitro in healthy volunteers, as seen by measuring ISG15 serum levels (1). A process mediated by ISG15, ISGylation, has been described to have a role in immunomodulation after bacterial infection (2). HCV also induces ISG15 expression (3).
Briefly, ISG15 expression seems to regulate, at least in part, Type I interferon signaling, translation, chromatin remodeling, cell motility, protein trafficking, and protein conjugation (ISGylation). Still, the complete spectrum of ISG15-dependent biological sequelae re-mains to be fully elucidated.
Further characterization of new ISG15 target proteins and the role of free ISG15 may offer new insights into mechanistic and immuno-therapeutic approaches to human diseases.
Tools to detect ISG15 should be able to detect both bound and free-ISG15, and have no cross-reactivity with ubiquitin (e.g. anti-human ISG15, clone 2.1), as this may hinder the interpretation of results found with biological samples.
- D’Cunha, J. et al. Journal of Immunology, 1996, 157:4100.
- Dieterich, C. & Relman, D.A. PLoS ONE 6(11): e27535. doi:10.1371/journal.pone.0027535.
- Arnaud, N. et al. PLoS Pathog, 2011, 7(10): e1002289. doi: 10.1371/journal.ppat.1002289.
Studying the role of ISG15 in your experimental model?
Leave a comment regarding the research tools you are using to investigate the role of ISG15 in IFN signaling pathway !
The Janus kinase (JAK) / Signal Transducer and Activator of Transcription (STAT) pathway a key regulator of cellular proliferation, differentiation, migration, apoptosis and survival. Numerous cytokines, growth factors and Interferons interact with the JAK/STAT signaling pathway which in turn regulates many biological processes, especially in hematopoietic development and immune responses.