Structural Studies of a New Class of Immune Checkpoint Inhibitor for Cancer Immunotherapy
Physical and Biological Sciences
Chemistry and Biochemistry
Natural Killer (NK) cells are a key component of the innate immune system that play a role in eliminating both tumors and virus-infected cells. NK cells express a deactivating receptor, KIR2DL3, which inhibits their cytotoxic function when bound by its ligand, class I MHC. Lirilumab, an Anti-KIR antibody (mAb) in clinical trials, prevents deactivation of the NK cell by binding to the KIR2DL3 receptor. However, the structural basis of lirilumab’s disruption of KIR2DL3 activity is unknown. To that end, the first aim of this project is to use X-ray crystallography to determine the structure of the lirilumab-KIR2DL3 complex to reveal how the antibody blocks MHC binding to the KIR receptor. A series of expression constructs for the KIR2DL3 receptor with different tag configurations for affinity chromatography were cloned then expressed in HEK293 and CHO cells. Biolayer interferometry assays demonstrate binding of an expressed and purified KIR2DL3 receptor with a control mAb and will also be used to determine lirilumab’s affinity. Identification of stable expression constructs, as well as structural epitopes of the KIR-mAb construct, will implement a foundation for the study of the Lirilumab mAb as a cancer therapeutic.
