Invitrogen™ ISG15 Monoclonal Antibody (1031CT2.8.3)

Ubiquitin-like protein ISG15 plays a key role in the innate immune response to viral infection either via its conjugation to a target protein (ISGylation) or via its action as a free or unconjugated protein. It is secreted from monocytes in response to type I interferons and causes natural killer (NK)-cell proliferation and an augmentation of non-MCH (major histocompatibility complex)-restricted cytotoxicity. Synthesis is stimulated by IFN-alpha or IFN-beta or IFN-omega, but not IFN-gamma. ISG15 expression is also induced by overexpression of interferon regulatory factors that participate in transcriptional regulation of IFN genes, and by influenza B virus. ISG15 is secreted by cell lines of monocyte, T-lymphocyte, B-lymphocyte, human fibroblasts, and epithelial origins. Enhancement of NK cell proliferation, augmentation of non-major histocompatibility complex-restricted cytotoxicity, and induction of IFN-gamma from T cells identify ISG15 as a member of the cytokine cascade and suggest that it may be responsible for amplifying and directing some of the immunomodulatory effects of IFN-alpha or IFN-beta. ISG15 has has also been shown to function intracellularly as a ubiquitin homolog. Mutations affecting the gene can result in Immunodeficiency 38, with basal ganglia calcification (IMD38).