Alternative titles; symbols
HGNC Approved Gene Symbol: CD160
Cytogenetic location: 1q21.1 Genomic coordinates (GRCh38) : 1:145,719,499-145,739,288 (from NCBI)
Anumanthan et al. (1998) isolated the gene encoding BY55 by COS cell expression cloning using mRNA pooled from natural killer (NK) cells of 4 donors. The sequence of the 1.3-kb cDNA transcript predicts a cysteine-rich, glycosylphosphatidylinositol (GPI)-anchored protein of 181 amino acids. The protein contains 2 N-linked glycosylation sites and a single extracellular Ig-like (see 147100, 300137) domain weakly homologous to MHC binding receptors collectively referred to as killer inhibitory receptors (KIR). Northern blot analysis detected BY55 in only spleen, peripheral blood, and small intestine. BY55 mRNA expression is restricted to functional NK and T cytotoxic lymphocytes, specifically CD56(dim)/CD16+ NK cells and CD8+,CD28-,CD11b+ peripheral blood or intestinal intraepithelial T lymphocytes. No expression was found in B-lymphocyte cell lines, T-cell leukemia cell lines, or a myeloid cell line. Maiza et al. (1993) showed that a monoclonal antibody to BY55 immunoprecipitated an 80-kD protein as well as a less abundant 27-kD protein from an NK-like cell line. Anumanthan et al. (1998) found that by reducing the immunoprecipitated BY55 protein with dithiothreitol and iodoacetamide, the relative amount of 27- to 80-kD protein could be increased, suggesting that the smaller predicted protein size is correct and that BY55 is a tightly disulfide-linked multimer. Phosphatidylinositol-specific phospholipase C cleaved BY55 from NK-like cell lines, confirming that BY55 protein is anchored to the cell surface via a GPI linkage.
Agrawal et al. (1999) demonstrated that optimal binding of BY55 requires prior aggregation of MHC class I complexes. They suggested that BY55 expression represents an additional and/or alternative pathway to CD28 (186760) stimulation in memory T lymphocytes lacking CD28, such as intestinal intraepithelial T cells which are BY55+.
Agrawal, S., Marquet, J., Freeman, G. J., Tawab, A., Bouteiller, P. L., Roth, P., Bolton, W., Ogg, G., Boumsell, L., Bensussan, A. Cutting edge: MHC class I triggering by a novel cell surface ligand costimulates proliferation of activated human T cells. J. Immun. 162: 1223-1226, 1999. [PubMed: 9973372]
Anumanthan, A., Bensussan, A., Boumsell, L., Christ, A. D., Blumberg, R. S., Voss, S. D., Patel, A. T., Robertson, M. J., Nadler, L. M., Freeman, G. J. Cloning of BY55, a novel Ig superfamily member expressed on NK cells, CTL, and intestinal intraepithelial lymphocytes. J. Immun. 161: 2780-2790, 1998. [PubMed: 9743336]
Maiza, H., Leca, G., Mansur, I. G., Schiavon, V., Boumsell, L., Bensussan, A. A novel 80-kD cell surface structure identifies human circulating lymphocytes with natural killer activity. J. Exp. Med. 178: 1121-1126, 1993. [PubMed: 7688788] [Full Text: https://doi.org/10.1084/jem.178.3.1121]