T cells recognizing an HLA-DQ alpha beta heterodimer encoded in cis by the DR4DQw4 haplotype and in trans by DR4DQw8/DRw8DQw4 heterozygous cells.

We generated alloreactive DQ-specific CD4+ T-lymphocyte clones. One of these (TLC HH58) was only restimulated with cells having the DR4DQw4 haplotype or cells being DR4DQw8/DRw8DQw4 heterozygous. The former cells carry the DQA1*0301 and DQB1*0401 alleles in cis position while the latter cells carry DQA1*0301 and DQB1*0402 alleles (DQB1*0402 is identical to DQB1*0401 except for codon 23) in trans position. Thus, very similar DQ alpha beta heterodimers are encoded by these genes in both cis and trans positions, which are recognized by the same T cells.