Phosphoantigen activation induces surface translocation of intracellular CD94/NKG2A class I receptor on CD94 super(-) peripheral V gamma 9 V delta 2 T cells but not on CD94 super(-) thymic or mature gamma delta T cell clones

• Published in: European journal of immunology 1998-11, Vol.28 (11), p.3399-3410
• Main Authors: Boullier, S, Poquet, Y, Halary, F, Bonneville, M, Fournie, J-J, Gougeon, M-L
• Format: Article
• Language: English
• ISSN: 0014-2980

Most adult peripheral blood gamma delta T cells express V gamma 9/V delta 2-encoded TCR that recognize a restricted set of nonpeptidic phosphorylated compounds, referred to as phosphoantigens. They also express various MHC class I-specific inhibitory receptors (IR), in particular CD94/NKG2-A heterodimers, which participate in the fine tuning of their TCR-mediated activation threshold. Most mature V gamma 9/V delta 2 T cells express surface CD94 receptors, unlike cord blood or thymus-derived V gamma 9/V delta 2 clones, thus suggesting a role for the microenvironment in IR expression. In the present study we show that most CD94 super(-) V gamma 9V delta 2 PBL ex vivo express an intracellular pool of CD94/NKG2-A receptors that is translocated to the cell surface upon activation by phosphoantigens or IL-2. In stark contrast, intracellular CD94/NKG2-A complexes are undetectable in CD94 super(-) thymus or PBL-derived mature V delta 2 T cell clones, and no surface induction is observed following phosphoantigen activation of T cell clones. Altogether these results provide new insights into the regulation of CD94/NKG2-A expression on T lymphocytes and suggest the existence of distinct mechanisms controlling in vivo and in vitro induction of IR on these cells.