Functional Inactivation in the Whole Population of Human Vγ9/Vδ2 T Lymphocytes Induced By a Nonpeptidic Antagonist

Nonpeptidic compounds stimulate human T cells bearing the TCR-γδ in the absence of major histocompatibility complex restriction. We report that one of these ligands, 2,3-diphosphoglyceric acid (DPG), which induces expansion of Vγ9/Vδ T cells ex vivo, antagonizes the same cell population after repetitive activation. Stimulation with DPG results in partial early protein tyrosine phosphorylation and a prolonged, but reversible, state of unresponsiveness to agonist ligands in Vγ9/Vδ2, but not in other T cells. These findings show that TCR antagonism is a general phenomenon of T cells. However, in contrast to the clonal specificity of altered peptides antagonizing αβ T cells, all the tested Vγ9/Vδ2 polyclonal cell lines and clones become unresponsive, a fact that may be relevant for the regulation of their response in vivo.