Recognition of a particular HLA-DQ heterodimer by a human gamma/delta T cell clone.

Peripheral blood mononuclear cells from a single donor were depleted of T cell receptor (TcR) alpha/beta T cells, stimulated with allogeneic cells, and gamma/delta T lymphocyte clones (TLC) were isolated by limiting dilution. Five TLC were cytotoxic against B-lymphoblastoid cell lines from the stimulating cell donor, and demonstrated a restricted allospecificity in panel cell studies. One of these, gamma/delta TLC RNG-135, was studied in more detail. Its phenotype was CD3+ TcR alpha/beta - TcR gamma/delta + BB3- delta TCS1+ CD4- CD8-. Inhibition experiments using monoclonal antibodies indicated that the cytotoxicity of TLC RNG-135 was mediated through the TcR gamma/delta, and directed against an HLA-DQ molecule. In extended panel cell experiments, this gamma/delta TLC only lysed cells carrying the DQA1*0501 and DQB1*0301 genes, either in cis position (on the DR5, DQw7 haplotype), or in trans position (the donor of the stimulating cells, DR3,4; DQw2, w7). Thus, it appears that gamma/delta T cells may recognize a particular HLA-DQ alpha/beta heterodimer, which may be encoded by DQA1 and B1 genes both in cis and trans position.