The power of proteins – a brief history
By the turn of the 20th century, most of the 20 common amino acids that form the protein “backbone” had been discovered. Scientists also had identified certain proteins, called enzymes, that could catalyze chemical reactions, and others, called antibodies, that could stimulate the body’s immune response to foreign “antigens.”
A groundbreaking discovery in 1922 demonstrated the unique power of proteins. That year, Canadian researchers used a purified extract of insulin, which they had isolated from the pancreas, to save the life of a 14-year-old diabetic boy. Within a year, the manufactured protein became available worldwide. For the first time in history, there was an effective treatment for diabetes.
In the early 1970s, a succession of key developments in genetics and immunology opened the door to protein therapeutics. The ability to transplant genes between different species led to the development and marketing of the first genetically engineered drug, human insulin, in 1982, followed by human growth hormone in 1985, and the first genetically engineered vaccine, to fight hepatitis B, in 1986.
Nine years earlier, in 1975, British researchers Georges Köhler and César Milstein figured out a way to fuse antibody-producing cells from immunized mice with antibody-secreting mouse cells derived from a type of cancer called myeloma. The result was a “hybridoma,” a line of hybrid cells that could be grown indefinitely and, when injected into mice, could produce large amounts of “monoclonal” antibodies, mass-produced to recognize a specific molecular target.
Genetic engineering techniques were used to “humanize” the mouse antibodies so they were less likely to be rejected by the body’s immune system. Since 1986, the U.S. Food and Drug Administration has approved 11 monoclonal antibodies, primarily to prevent rejection of transplanted organs and combat cancer. Herceptin, approved in 1998, is a monoclonal antibody used in the treatment of breast cancer.