On the trail of empty MHC class-I

Abstract Since being proposed nearly 25 years ago that MHC-I molecules free of peptide ligand possess a conformation that is distinct from that of the mature loaded form, considerable research has been conducted in order to isolate and characterise such a species. While some progress has been made in our understanding, many questions still surround the nature and loading of empty MHC-I. However, the necessary tools to address these questions may finally be at hand.