Recombinant Human PILR-beta Fc Chimera Protein, CF

Paired immunoglobulin-like type 2 receptor beta (PILR-beta) is a type I transmembrane (TM) glycoprotein belonging to the Ig superfamily. PILR-beta is the activating counterpart to the immunoreceptor tyrosine-based inhibitory motif (ITIM) containing PILR-alpha inhibitory receptor (1). Mature human PILR-beta is a 208 amino acid (aa) protein containing a 172 aa V-type Ig-like extracellular domain (ECD) with a siglec-like fold, a single TM, and a truncated cytoplasmic tail (2, 3). The TM of PILR-beta contains a positively-charged residue which interacts with immunoreceptor tyrosine-based activation (ITAM)-bearing adaptor molecules (2). The ECD of mature human PILR-beta shares 40% aa sequence identity with its mouse counterpart. PILR-beta is expressed on myeloid cells, such as natural killer, macrophage, and dendritic cells, as well as resident cells of the central nervous system, such as microglial cells (2,4). It is a binding partner for DAP12 and CD99, and has been shown to play an important role in innate immunity and inflammation (4-6). The PILR-alpha / beta pair have also been shown to regulate cell signaling via association with SHP-1 (7). Experiments studying the effects of S. aureus and T. gondii infections in mice have shown that up-regulation of PILR-beta led to significantly lower survival rates while knock-down of PILR-beta or activation of PILR-alpha resulted in significantly less inflammation and increased pathogen clearance (4,5).