Natural killer (NK) cells are a distinct lineage of lymphocytes that mediate cytotoxic activity and secrete cytokines upon immune stimulation. Several genes of the C-type lectin superfamily, including members of the NKG2 family, are expressed by NK cells and may be involved in the regulation of NK cell function. CD94 (Cluster of Differentiation 94), also known as killer cell lectin-like receptor subfamily D, member 1 (KLRD1), is a lectin, cluster of differentiation and a receptor that is involved in cell signaling and is preferentially expressed on the surface of NK cells and is classified as a type II membrane protein because it has an external C terminus. KLRD1 has two alternatively spliced variants that differ in the presence or absence of exon 2 sequence. CD94 pairs with the NKG2 molecule as a heterodimer which expressed on the surface of natural killer cells and a subset of CD8+ T-lymphocyte interacts with non-classical MHC glycoproteins class I (HLA-E in human and Qa-1 molecules in the mouse). These receptors stimulate or inhibit cytotoxic activity of NK cells, therefore they are divided into activating (NKG2C, NKG2E, NKG2H and NKG2D) and inhibitory (NKG2A and NKG2B) receptors according to their function.
Protein expression analysis
Strain specific CD94 expression analysis in homozygous B-hCD94 mice by flow cytometry. Splenocytes were collected from WT and heterozygous B-hCD94 (H/+) mice, and analyzed by flow cytometry with species-specific anti-CD94 antibody. Mouse CD94 was detectable in WT and heterozygous B-hCD94 (H/+) mice. Human CD94 was exclusively detectable in heterozygous B-hCD94 but not WT mice.