A family of inhibitory and activating Ig-like receptors that modulate function of lymphoid and myeloid cells

Recently, we and others have discovered a family of receptors, called immunoglobulin (Ig)-like transcripts (ILTs), leukocyte Ig-like receptors (LIRs), or monocyte/macrophage Ig-like receptors (MIRs). ILT/LIR/MIRs are genetically, structurally and functionally related to a group of NK cell receptors for HLA class I molecules called Killer cell Ig-like receptors (KIRs). Distinct ILT/LIR/MIR isotypes ore differentially expressed on myeloid and lymphoid cell subsets and some of them recognize HLA class I. Whereas so me isotypes inhibit others induce cell activation. Here we review what is known about their structure, distribution, biochemical and functional characteristics.