Applications in Medicine

Genetic engineering lets scientists take the gene for a useful human protein and place it into a fast-growing, easily cultured host — usually a bacterium, sometimes a yeast or even a transgenic animal — so that the host manufactures the protein in bulk. Before this was possible, therapeutic proteins had to be purified directly from human or animal tissue, which was expensive, slow, limited in supply, and sometimes risky (animal-derived proteins could trigger immune reactions, and tissue-derived proteins could carry infectious agents). Medicine has been transformed by this shift: recombinant hormones such as insulin and growth hormone, clotting factors, interferons and a whole new generation of vaccines are now manufactured to a consistent, controllable standard. The sections that follow work through each of these …