Assessment of copy-number variation in the NKG2C receptor gene in a single-tube and characterization of a reference cell panel, using standard polymerase chain reaction.

Natural killer (NK) and T-lymphocytes monitor human leukocyte antigen (HLA)E expression through CD94:NKG2 heterodimers. Structural polymorphism is not a hallmark for NK-complex genes on chromosome 12, except for complete NKG2C deletion in some humans. We present a method for fast, simple and accurate assessment of NKG2C copy-number variation – presence or absence in the genome of an NKG2C gene, in homo- or heterozygosis, is detected by a single conventional polymerase chain reaction that yields amplicons of different lengths in each genotype. We have also determined the NKG2C genotypes of a reference cell panel comprising 13 NK- and tumour-cell lines and 39 Epstein-Barr virus transformed cells from the International Histocompatibility Workshop. Our results should facilitate research on the importance of NKG2C and its deletion for immunity. Natural killer (NK) cells and CD8+ cytotoxic T-lymphocytes (CTL) are key components of the cellular immune response to infections and tumours. While CTLs recognize target cells in an antigen-dependent manner, NK cells detect and kill, without previous sensitization, cells displaying altered molecular patterns. Mammal NK cells sense major histocompatibility complex (MHC) expression through at least four families of receptors, all of which include both activating and inhibitory members. Paired inhibitory/activating receptors are believed to balance NK-cell behaviour in the presence of a potential target cell, and an important set of these receptors are also expressed on CTLs (1). Inhibitory MHC receptors are fundamental to the missing self-model of NK-cell regulation (2). In contrast, the role of their activating counterparts in immunity is obscure – whilst some may recognize pathogenencoded (3) or -modified molecules, most activating homologues of inhibitory MHC receptors have self or unknown