Structural biology of complex of rat NK cell receptors NKR-P1B and Clrb

The Natural Killer (NK) cells have an important role in the nonspecific immunity of the or- ganism. They have the ability to identify and to kill tumor cells and cells infected by a virus without preceding sensitization by antigen. Their function is directed by the amount of sti- mulation and inhibition receptors interacting with ligands on the tumor or infected cell. This thesis focuses on the preparation and the study of the complex of rat NK cellular inhi- bition receptor NKR-P1B ("natural killer cell receptor - protein 1B") and its ligand Clrb ("C-type lectin-related ligand b"). The Clrb initiates the inhibition of NKR-P1B, meaning that if the cell express Clrb, it won't be destroyed. If the cell gets infected by the rat cytome- galovirus, it loses Clrb from its surface and its destruction is therefore no longer prevented. Cells infected with this virus defend themselves from destruction by expression of the viral gene of C-type lectin RCTL, which is a homolog of Clrb. Transient transfection of human embryonic kidney 293 cell line with simple glycosylation (HEK293S GnTI− ) was used for the recombinant preparation of the soluble form of these two receptors of the rat NK cells. The native forms of the receptors - disulfidic homo- dimers - were prepared as the fusion construct with IgG Fc (using..