How do NK cells sense the expression of HLA-G class Ib molecules?

The nature of NK cell receptors involved in recognition of HLA-GI has remai ned an unclear issue; we herein review this topic based on our experience. We found no evidence that well characterized p58 and p70 KIRs may interact with HLA-G1. By contrast, our data support that NK recognition of cells exp ressing HLA-GI involves at least two nonoverlapping receptor-ligand systems : (1) the direct engagement of the ILT2 (LIR1) receptor by HLA-G1; and (2) the interaction of CD94 / NKG2A and CD94 / NKG2C receptors with the non-cla ssical class I molecule HLA-E, co-expressed on the surface upon binding to a nonamer (VMAPRTLFL) from the HLA-G leader sequence.