Description: The monoclonal antibody 42D1 recognizes the CD85d protein also known as ILT4, LIR-2. It is a member of the ILT (immunoglobulin-like transcript)/ LIR (leukocyte Ig-like receptor), MIR (monocytes Ig-like receptor) family. CD85d is a 110 kDa single transmembrane receptor with 3 Ig-like domains and a long cytoplasmic domain containing ITIMs (immunoreceptor tyrosine-based inhibitory motifs). Expression is confined to monocytes, macrophages and dendritic cells. The ligand for CD85d is non-classical class I HLA-G, -B and G1. Upon ligand binding, tyrosine phosphatase SHP-1 interacts with the ITIM. Interaction of HLA-G with ILT4/CD85d is thought to contribute to tolerance during fetal implantation. Additionally, it is the levels of ILT3 and ILT4 on DCs that suggests a role in organ allograft rejection.
Crosslinking of the receptor with the monoclonal antibody 42D1 inhibits calcium flux as well as enhancing HLA-G tetramer staining and restoring the stimulating activity of tolerogenic DC.