IFN-γ, an acid-labile interferon, is produced by CD4 and CD8 T lymphocytes as well as activated NK cells. Its receptors are widespread in immune cells, triggering an increase in class I MHC protein surface expression upon IFN-γ signaling. This enhancement aids in antigen presentation to T-helper (CD4+) cells. IFN-γ signaling in antigen-presenting cells, B and T lymphocytes involved in antigen recognition, plays a crucial role in regulating the antigen-specific phases of the immune response. Moreover, IFN-γ stimulates various functions in lymphoid cells, including the anti-microbial and anti-tumor responses of macrophages, NK cells, and neutrophils. Notably, Human IFN-γ is species-specific and exhibits biological activity exclusively in Human and primate cells. Recombinant Human IFN-γ is a 16.8 kDa protein composed of 144 amino acid residues.