Identification of the CD85 antigen as ILT2, an inhibitory MHC class I receptor of the immunoglobulin superfamily.
Banham AH., Colonna M., Cella M., Micklem KJ., Pulford K., Willis AC., Mason DY.
The CD85 molecule was originally defined at the Fifth Workshop on Leucocyte Antigens in 1993 by two monoclonal antibodies, VMP55 and GHI/75. This cell-surface glycoprotein is expressed on B cells, monocytes, and subpopulations of T and natural killer (NK) cells, and particularly high levels are expressed by normal and neoplastic plasma cells and by hairy cell leukemia B cells. We affinity purified the CD85 antigen and obtained tryptic peptide sequence which indicated that this molecule might be ILT2, a recently described inhibitory major histocompatibility complex class I receptor of the immunoglobulin superfamily. This was confirmed by showing that both of the original anti-CD85 mAbs stained ILT2 transfectants. The cell signaling role demonstrated for ILT2 is consistent with the previously reported involvement of CD85 in T cell activation.