Production of therapeutic proteins in the milk of transgenic livestock

With the advent of the Human Genome Project and associated developments in 'functional genomics', there are going to be increasing numbers of proteins identified and developed for clinical use. There are a number of production methods available, although only three, bacterial, yeast and mammalian cell culture, have produced recombinant proteins that have been approved for clinical use. Nevertheless other production systems are under development, and one, the production of human proteins in the milk of transgenic livestock, is showing great promise, with two proteins now in clinical trials. This chapter will compare and contrast the various competing technologies and will then concentrate on factors influencing the choice and use of the transgenic system.