Leukocyte immunoglobulin-like receptor subfamily B member 5 (LILRB5)

Leukocyte immunoglobulin-like receptor subfamily B member 5 (LILRB5) is an inhibitory receptor expressed predominantly on myeloid lineage cells, including monocytes, macrophages, neutrophils, dendritic cells, and certain tumor cells[4]. It belongs to the subfamily B class of LIR receptors, characterized by multiple extracellular immunoglobulin domains and cytoplasmic ITIM motifs that recruit signaling phosphatases, thereby modulating activation thresholds of immune cells[1][2][4]. LILRB5 is unique in its ability to bind free heavy chains of HLA-class I molecules—notably the dimeric form of HLA-B27—distinguishing it from other LIR receptors that bind β2-microglobulin-associated HLA complexes[2][5]. By regulating innate and adaptive immune responses, LILRB5 plays roles in inflammation, infection, tumor immunity, and tissue injury response[2][4]. Its expression is associated with prognosis in several cancers, highlighted as a potential biomarker and target for future immunomodulatory therapies, though no approved drugs currently target LILRB5 specifically[2][4].

Other names

LILRB5LIR-8CD85c

For potential drugs: inhibitory receptor engagement leading to recruitment of phosphatases (SHP1/2), resulting in negative regulation of cell activation and downstream immune suppression. Signal transduction via ITIM motifs upon ligand binding (e.g., MHC class I molecules), culminating in dephosphorylation of signaling proteins and dampening immune responses.