Abstract: Macrophages and precursor monocytes are activated to exhibit tumoricidal activity by stimulation solely with granulocyte-macrophage colony stimulating factor. A patient suffering from tumors can be treated by direct administration of therapeutically effective quantities of activated granulocyte-macrophage colony stimulating factor. Homogeneous granulocyte-macrophage colony stimulating factor for use in activating macrophages and monocyte precursors is prepared by recombinant DNA techniques. The gene coding for granylocyte-macrophage colony stimulating factor is isolated and then recombinant protein product expressed in an appropriate expression system. The granulocyte-macrophage colony stimulating factor recovered from the expression system is purified to homogeneity by reverse phase high-performance liquid chromatography.

Abstract: A process for preparing bovine interleukin-2 (bIL-2) by culturing a microbial host transformed by a vector containing a DNA sequence encoding bIL-2 under conditions suitable for the expression of bIL-2 and recovering bIL-2.

Abstract: A chemically-synthesized oligonucleotide composing a portion of the nucleotide sequence of the human IL-2 is employed as a probe to isolate the gene coding for human IL-2. The human IL-2 gene is selected from a cDNA library prepared from RNA produced by mitogen-stimulated Jurkat cells. Double-stranded cDNA is prepared from polyadenylated RNA extracted from bovine cells thought to produce interleukin-2. Such cDNA is inserted within a plasmid vector and the recombinant plasmid employed to transform hosts. Plasmid DNA, prepared from pools of the transformed hosts, is hybridized with a probe composed of a large portion of the coding sequence of the human IL-2 gene. Pools of host cells that provide signal to the human cDNA probe are identified, subdivided, and rescreened until a single positive colony is identified. Bovine plasmid cDNA is prepared from this colony, and the bIL-2 gene is sequenced.

Abstract: A hybrid polypeptide composed of an identification peptide and a desired functional protein are produced by recombinant DNA techniques. A DNA expression vector is constructed that includes segments of DNA coding for the identification peptide and the desired functional protein. The identification peptide consists of a highly antigenic N-terminal portion and a C-terminal linking portion that connects the identification peptide to the N-terminal of the functional protein. The linking portion of the identification peptide is cleavable at a specific amino acid residue adjacent the functional protein by use of a sequence specific proteolytic enzyme or chemical proteolytic agent. The hybrid polypeptide expressed by the host cells transformed by the cloning vector is removed therefrom and purfied by affinity chromatography techniques by use of an immobilized ligand specific to the antigenic portion of the identification peptide.