Simponi (golimumab) is a human IgG1k monoclonal antibody specific for human tumor necrosis factor alpha (TNFa). It was created using genetically engineered mice immunized with human TNF, resulting in an antibody with human-derived antibody variable and constant regions. Simponi is produced by a recombinant cell line cultured by continuous perfusion and is purified by a series of steps that includes measures to inactivate and remove viruses.