| Citation | Distinguished for studies on the relationship between molecular structure and biological activity, particularly relating to antigen-antibody interactions and cell-surface receptors. Among Crumpton's major early achievements was the determination of the molecular basis of the antigenicity of globular proteins. He isolated a series of antigenically active peptides from myoglobin and identified those parts of the molecule which determined the antigenic combining site. He also showed that small changes in the conformation of myoglobin led to changes in antigenic reactivity. This work helped establish the general concept that the antigenicity of globular proteins is conformation-dependent, a concept that has influenced work on the activity of blood group substances and virulence and protection in micro-organisms. He further showed with myoglobin that the antibody itself could induce conformational changes in the antigen. More recently, Crumpton has turned his attention to antigenic determinants present in cell surfaces, particularly in the lymphocyte. He developed a currently widely used method for solubilising surface membrane proteins with detergents followed by affinity chromatography which has led to an effective purification of human histocompatibility (HL-A) antigens. It has thus been possible to suggest that the A and B (transplantation) antigens have arisen by duplication of a common primordial gene and that the structure of the Ia (immune-associated) antigens is quite different. Crumpton has also contributed to the problem of the organisation of cell surface constituents in relationship to transfer of information for cellular adaptation via surface receptors and C++, as exemplified by the action of mitogenic substances on the lymphocyte. |