Recombinant Human LILRB5/CD85c/LIR-8 Fc Chimera Protein, CF

LIR8, also known as CD85c and LILRB5, belongs to the Leukocyte immunoglobulin-like receptors (LILR) family of transmembrane glycoproteins involved in regulating immune responses (1,2). There are at least thirteen LILR family members and are divided into activating (LILRA) or inhibiting (LILRB) molecules (1,2). Mature human LIR8 consists of an extracellular domain (ECD) with four Ig-like domains, a transmembrane segment, and a cytoplasmic domain with two immunoreceptor tyrosine-based inhibitory motifs (ITIM). Alternative splicing of human LIR8 generates at least 2 isoforms, one lacking the second Ig-like domain. The LILR family appears to be primate-specific receptors in terms of sequence homology. LIR8 is expressed on NK cells and in the tryptic granules of mast cells and negatively regulates immune cell activation (3, 4). It is present on the mast cell surface following cell activation and degranulation (4). Activated mast cells may also release soluble forms of LIR8 (3). LIR8 has also been shown to be expressed on T cells and induce CD8+ T cell proliferation (5).  Consistent with the demonstrated binding of LILRB2 to Angiopoietin-like 2 and 5 (6), R&D Systems in-house testing indicates that LIR8 binds to Angiopoietin-like 7. Recently, a common missense variant of LIR8 was found to be associated with statin intolerance and myalgia (7).