The applications of monoclonal antibodies are now widespread, as research tools, as
in vitro
diagnostic reagents and, increasingly, as
in vivo
diagnostic and therapeutic products. The number of antibody therapeutics on the market and in clinical trials has increased rapidly in recent years and global production has now reached tonnage quantities. Manufacturing technology is for the most part based on mammalian cell culture in fed‐batch suspension culture. Improvements in cell‐line construction and in media and feeds have led to dramatic improvements in productivity. Titers of grams per liter are now seen routinely and, increasingly, this is being achieved in media that are chemically defined and protein‐free. The requirement for very large quantities of antibody products also presents a challenge in terms of purification processes. Currently, purification is based on column chromatography, typically with a Protein‐A affinity step early in the process. In addition to optimizing processes for productivity, there is a growing awareness of the need to design cells and processes to deliver products with desired structural features.