The Repertoire of Killer Cell Ig-Like Receptor and CD94:NKG2A Receptors in T Cells: Clones Sharing Identical αβ TCR Rearrangement Express Highly Diverse Killer Cell Ig-Like Receptor Patterns

Abstract

Killer cell Ig-like receptor (KIR) and CD94:NKG2A molecules were first defined as human NK cell receptors (NKR), but now are known to be expressed and to function on subpopulations of T cells. Here the repertoires of KIR and CD94:NKG2A expression by T cells from two donors were examined and compared with their previously defined NK cell repertoires. T cell clones generated from peripheral blood of both donors expressed multiple NKR in different combinations and used the range of receptors expressed by NK cells. In both donors αβ T cells less frequently expressed the inhibitory receptors CD94:NKG2A and KIR2DL1 than either γδ T cells or NK cells. In contrast to NK cells, not all NKR+ T cells expressed an inhibitory receptor for autologous HLA class I. This lack of specific inhibitory NKR was especially apparent on αβ T cells of one donor. Overall, αβ T cells exhibited a distinct pattern of NKR expression different from that of γδ T and NK cells, which expressed highly similar NKR repertoires. In one donor, analysis of TCR rearrangement revealed a dominant subset of NKR+ T cells sharing identical TCR α- and β-chains. Remarkably, among 55 T cell clones sharing the same TCRαβ rearrangement 18 different KIR phenotypes were seen, suggesting that KIR expression was initiated subsequently to TCR rearrangement.