Identification of (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate as a major activator for human γδ T cells in Escherichia coli

The gcpE and lytB gene products control the terminal steps of isoprenoid biosynthesis via the 2-C-methyl-D-erythritol 4-phosphate pathway in Escherichia coli. In lytB-deficient mutants, a highly immunogenic compound accumulates significantly, compared to wild-type E. coli, but is apparently absent in gcpE-deficient mutants. Here, this compound was purified from E. coli Delta lytB mutants by preparative anion exchange chromatography, and identified by mass spectrometry, H-1, C-13 and P-31 NMR spectroscopy, and NOESY analysis as (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP). HMB-PP is 10(4) times more potent in activating human V gamma9/V delta2 T cells than isopentenyl pyrophosphate. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.