Definition

A recombinant form of the endogenous cytokine interferon-gamma (IFN-gamma; IFNg), with a peptide length of 140 amino acids and modified with an N-terminal methionyl group, with potential immunomodulating and antineoplastic activities. Upon administration, IFNg-1b binds to IFNg cell surface receptors (IFNGRs), activates IFNg-stimulated signaling pathways, including the JAK-STAT pathway, and leads to the transcription of multiple IFNg-controlled genes, the expression of which may activate certain components of the immune system. IFNg activates natural killer (NK) cells, macrophages, and cytotoxic T lymphocytes (CTLs), stimulates antibody-dependent cellular cytotoxicity (ADCC) and induces the expression of major histocompatibility complex (MHC) molecules, which leads to an increase in antigen presentation, including tumor-associated antigens (TAAs), to the immune system, and modulates the expression of certain pro-inflammatory cytokines by antigen-presenting cells (APCs). Altogether, this increases tumor cell killing. IFNg-1b, a cell-signaling protein, plays a key role in the regulation and activation of the immune system.