Figure 4. Function and polymorphism of human killer cell immunoglobulin-like receptors.

The receptors are grouped according to their activating and inhibitory functions, in which regard KIR2DL4 is unique having structural elements associated with both activation and inhibition. Under allotypes is given the number of protein variants for each KIR as given in the KIR database (www.ebi.ac.uk/ipd/kir/) of the Immuno Polymorphism Database (IPD), as last updated on the 20^th February 2009. Under MHC class I ligands is given the reactivity of each KIR with HLA class I.