A type II interferon that is a translation product of the human IFNG gene or a 1:1 ortholog thereof. The core domain structure consists of an Interferon gamma domain (Pfam:PF00714) that is four-helical cytokine domain with an additional helix in one of the crossover connections. It is a cytokine produced by lymphocytes activated by specific antigens or mitogens that has important immunoregulatory functions. [ PRO:CNA ]