Rodney Porter was a biochemist who spent most of his professional life investigating the chemical structure and functioning of antibodies, a class of proteins which are also called immunoglobulins. Since 1890 scientists had known that antibodies are found in the blood serum and provide immunity to certain illnesses. However, when Porter began his research in the 1940s, little was known about their chemical structure, or how antigens (substances that cause the body to produce antibodies) interacted with them. Using the results of his own research as well as that of Gerald M. Edelman, Porter proposed the first satisfactory model of the immunoglobulin molecule in 1962. The model allowed the development of more detailed biochemical studies by Porter and others that led to a better understanding of the way in which antibodies worked chemically. Such understanding was key to research on the prevention and cure of a number of diseases and the solution to problems related to organ transplant rejection. For his work, Porter shared the 1972 Nobel Prize in physiology or medicine with Edelman.
Rodney Robert Porter was born October 8, 1917, in Newton-le-Willows, near Liverpool in Lancashire, England. His mother was Isobel Reese Porter and his father, Joseph L. Porter, was a railroad clerk. "I don't know why I became interested in [science]," Porter once told the New York Times. "It didn't run in my family." He attended Liverpool University, where he earned a B.S. in biochemistry in 1939. During World War II he served in the Royal Artillery, the Royal Engineers, and the Royal Army Service Corps, and participated in the invasions of Algeria, Sicily, and Italy. After his discharge in 1946, he resumed his biochemistry studies at Cambridge University under the direction of Frederick Sanger.
Porter's doctoral research at Cambridge was influenced by Nobel laureate Karl Landsteiner' s book, The Specificity of Serological Reactions, which described the nature of antibodies and techniques for preparing some of them. Antibodies, at the time, were thought to be proteins that belonged to a class of blood-serum proteins called gamma globulins . From Sanger, who had succeeded in determining the chemical structure of insulin (a protein that metabolizes carbohydrates), Porter learned the techniques of protein chemistry. Sanger had also demonstrated tenacity in studying problems in protein chemistry involving amino acid sequencing that most believed impossible to solve, and he was a model for the persistence Porter would show in his later work on antibodies.
Fortunately, Porter chose rabbits to experiment on for his research. Although this was not known at the time, the antibody system is not as complex in this animal as it is in some. The most important antibody, or immunoglobulin, in the blood is called IgG, which contains more than 1,300 amino acids. The problem of discovering the active site of the antibody--the part that combines with the antigen--could be solved only by working with smaller pieces of the molecule. Porter discovered that an enzyme from papaya juice, called papain, could break up IgG into fragments that still contained the active sites but were small enough to work with. He received his Ph.D. for this work in 1948.
Porter remained at Cambridge for another year, then in 1949 he moved to the National Institute for Medical Research at Mill Hill, London. There, he improved methods for purifying protein mixtures and used some of these methods to show that there are variations in IgG molecules. He obtained a purer form of papaya enzyme than had been available at Cambridge and repeated his earlier experiments. This time the IgG molecules broke into thirds, and one of these thirds was obtained in a crystalline form which Porter called fragment crystallizable (Fc).
Obtaining the Fc crystal was a breakthrough; Porter now was able to show that this part of the antibody was the same in all IgG molecules, since a mixture of the different molecules would not have formed a crystal. He also discovered that the active site of the molecule (the part that binds the antigen) was in the other two-thirds of the antibody. These he called fragment antigen-binding (or FAB) pieces. After Porter's research was published in 1959, another research group, led by Gerald M. Edelman at Rockefeller University in New York, split the IgG in another way--by separating amino acid chains rather than breaking the proteins at right angles between the amino acids as Porter's papain had done.
In 1960 Porter was appointed professor of immunology at St. Mary's Hospital Medical School in London. There he repeated Edelman's experiments under different conditions. After two years, having combined his own results with those of Edelman, he proposed the first satisfactory structure of the IgG molecule. The model, which predicted that the FAB fragment consisted of two different amino acid chains, provided the basis for far-ranging biochemical research. Porter's continuing work contributed numerous studies of the structures of individual IgG molecules. In 1967 Porter was appointed Whitley Professor of Biochemistry and chairman of the biochemistry department at Oxford University. In his new position, Porter continued his work on the immune response, but his interest shifted from the structure of antibodies to their role as receptors on the surface of cells. To further this research, he developed ways of tagging and tracing receptors. He also became an authority on the structure and genetics of a group of blood proteins called the complement system, which binds the Fc region of the immunoglobulin and is involved in many important immunological reactions.
Porter married Julia Frances New in 1948. They had five children and lived in a farmhouse in a small town just outside of Oxford. Porter was killed in an automobile accident a few weeks before he was to retire from the Whitley Chair of Biochemistry. He had been planning to continue as director of the Medical Research Council's Immunochemistry Unit for another four years; he had also intended to continue his laboratory work, attempting to crystallize one of the proteins of the complement system. Porter's awards in addition to the Nobel Prize include the Gairdner Foundation Award of Merit in 1966 and the Ciba Medal of the Biochemical Society in 1967.
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