100  Years later: Celebrating the contributions of x-ray crystallography to XXXX and clinical immunology.

@entity1573 @entity566 @entity56
Current knowledge of molecules involved in immunology and @entity56 results from the significant contributions of x-ray crystallography, a discipline that just celebrated its 100th anniversary. The histories of allergens and x-ray crystallography are intimately intertwined. The first enzyme structure to be determined was lysozyme, also known as the @entity1573 food allergen Gal d 4. Crystallography determines the exact 3-dimensional positions of atoms in molecules. Structures of molecular complexes in the disciplines of immunology and @entity566 have revealed the atoms involved in  molecular interactions and mechanisms of disease. These complexes include peptides presented by MHC class II molecules, cytokines bound to their receptors, allergen-antibody complexes, and innate immune receptors with their ligands. The information derived from crystallographic studies provides insights into the function of molecules. Allergen function is one of the determinants of environmental exposure, which is essential for IgE sensitization. Proteolytic activity of allergens or their capacity to bind LPSs can also contribute to allergenicity. The atomic positions define the molecular surface that is accessible to antibodies. In turn, this surface determines antibody specificity and cross-reactivity, which are important factors for the selection of allergen panels used for molecular diagnosis and the interpretation of  clinical symptoms. This review celebrates the contributions of x-ray crystallography to clinical immunology and @entity566 , focusing on new molecular perspectives that influence the diagnosis and treatment of @entity56 .
