Functional analysis of the HLA-A2/Aw68 recombinant molecule HLA-Aw69: Epstein-Barr virus specific cytotoxic T cells restricted through Aw69 can utilise restricting determinants on Aw68 but not on A2

Epstein-Barr virus-specific cytotoxic T cell lines, expanded in interleukin 2-conditioned medium, have been generated in vitro from virus-immune individuals bearing either the common HLA-A2 antigen (A2.1), a variant A2 antigen (A2.2) or a novel antigen Aw69 which is a recombinant molecule having identity with HLA-Aw68 in the α1 domain and with HLA-A2 in the α2 and α3 domains. Virus-specific cytotoxic T cells restricted through A2.1 or A2.2 only recognised targets bearing the identical sub-type of A2 molecules and showed no cross-recognition of other A2 sub-types, of Aw68 or of Aw69. In contrast, virus-specific cytotoxic T cells restricted through the Aw69 antigen showed a significant cross-recognition of restricting determinants on Aw68 but not on A2 molecules. The results suggest that the α1 extracellular domain of the HLA-Aw69 molecule plays a predominant role in the formation of T cell restricting determinants.