Recombinant Mouse PIR-B Protein, CF

This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.

Paired immunoglobulin‑like receptor B (PIR‑B) is a transmembrane protein that acts as a negative regulator of immune responses. It is the rodent homolog of human LILRB1‑5 family proteins. It is most closely related to LILRB3 which is also known as ILT5, LIR‑3, and CD85a. Like LILRB family members, PIR‑B contains cytoplasmic immunoreceptor tyrosine‑based inhibitory motifs (ITIMs) that inhibit signaling events via phosphatase SHP‑1. PIR‑A and other LILRA family members instead contain cytoplasmic ITAMs which augment immune responses (1). Mature mouse PIR‑B is a 120 kDa glycoprotein that consists of a 618 amino acid (aa) extracellular domain (ECD) with six Ig‑like domains, a 21 aa transmembrane segment, and a 178 aa cytoplasmic domain with four ITIMs (2). The 85‑95 kDa human ILT5 contains four Ig‑like domains. Within common regions of their ECDs, mouse PIR‑B shares 73% and 55% aa sequence identity with rat PIR‑B and human ILT5, respectively. PIR‑B is expressed on dendritic cells, monocytes, macrophages, B cells, mast cells, neutrophils, eosinophils, basophils, osteoclasts, and cerebellar granule neurons (3‑10). Triggering of PIR‑B inhibits the activation of macrophages, mast cells, neutrophils, basophils, and B cells (5‑7, 9). PIR‑B also inhibits the differentiation of osteoclasts and pro‑inflammatory M1 macrophages (4, 11). PIR‑B interacts in cis and in trans with MHC I molecules to limit autoreactive humoral and cellular immune responses (12‑14). It suppresses anti‑bacterial inflammatory responses by blocking TLR9‑dependent B cell activation (14). In the CNS, PIR‑B functions as a receptor for the myelin proteins Nogo, MAG, and OMgp and mediates their inhibitory action on neurite outgrowth and axon regeneration (10). Upon binding to MAG, PIR‑B associates with TrkB and NGF R/p75 in cerebellar granule neurons (15).

Array 2754-PB

• PIR-B Antibodies
• PIR-B Proteins and Enzyme