Immunoglobulin-Like Transcript 2 (ILT2, CD85j) (APC)

The immunoglobulin-like transcript (ILT) family of activating and inhibitory type immunoreceptors are expressed on many leukocyte subsets and function in the regulation of immune responses (1-3). This family was also named leukocyte Ig-like receptors (LIR) and monocyte/macrophage Ig-like receptors (MIR). ILTs share significant homology with killer cell Ig-like receptors (KIR). The ILT genes are located on human chromosome 19q13.4 in the leukocyte receptor complex, which also include the genes encoding KIRs (4). With the exception of ILT6, which is a soluble molecule, all ILT family members are type I transmembrane proteins having two or four extracellular Ig-like domains (2, 3). One subset of the ILT receptors (referred to as subfamily B of the LIRs) has long cytoplasmic tails containing immunoreceptor tyrosine-based inhibitory motifs (ITIMs) that inhibit signaling events by recruiting SH2-containing protein tyrosine phosphatase-1. Another subset of the ILT receptors (referred to as subfamily A of the LIRs) contains activating receptors with short cytoplasmic regions that lack signal transduction motifs. These receptors contain a basic arginine residue within their transmembrane domains that allows association with Fcg R, an immunoreceptor tyrosine- based activation motif (ITAM)-bearing signal adapter protein (1-3). ILT2, also known as LIR1, MIR7, and CD85j, is expressed on most monocytes, dendritic cells, and mature B cells (1-3). It is also expressed on small percentages of T cells and NK cells. ILT2 has four extracellular Ig-like domains and three cytoplasmic ITIMs. It functions as an inhibitory receptor that prevents cellular activation. ILT2 has been shown to bind classical (HLA-A and -B) and non-classical (HLA-G1, -E and -F) MHC class I molecules (MHCI) (1-3). ILT2 also binds with high affinity to an MHCI homolog from human cytomegalovirus (3). Ligation of ILT2 by MHC I may function to poise cellular activation thresholds and inhibit various leukocyte effector mechanisms that are regulated by MHCI molecules on target cells. Applications: Suitable for use in Flow Cytometry. Other applications not tested. Recommended Dilution: Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4 degrees C before opening. DO NOT FREEZE! Stable at 4 degrees C as an undiluted liquid. Dilute only prior to immediate use. Stable for 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer. Freezing APC conjugates will result in a substantial loss of activity. APC conjugates are sensitive to light.