Sensing cell stress and transformation through Vγ9Vδ2 T cell-mediated recognition of the isoprenoid pathway metabolites

V gamma V delta 2 cells, a major peripheral blood gamma delta T cell subset in adults, recognize non-peptidic phosphorylated metabolites referred to as phosphoantigens (phosphoAg), which are produced by a broad array of prokaryotic and eukaryotic organisms. We will review here the biosynthetic pathways leading to production of phosphoAg and our current understanding of the mode of activation of V gamma 9V delta 2 cells by these compounds. We will also discuss the physiological relevance of this immune recognition process and show how it can enable discrimination by V gamma 9V delta 2 lymphocytes of infected and/or transformed cells. (c) 2005 Elsevier SAS. All rights reserved.