Human Interferon gamma-1b (140 residues), produced from E. coli. Production of Actimmune is achieved by fermentation of a genetically engineered Escherichia coli bacterium containing the DNA which encodes for the human protein. Purification of the product is achieved by conventional column chromatography. The sequence displayed is a cDNA sequence which codes for human interferon gamma, as described by Gray et. al. and not specifically interferon gamma 1b.