A novel nucleotide-containing antigen for human blood gamma delta T lymphocytes.
The stimulation of human gamma delta T cells by mycobacteria occurs through recognition of four distinct nonpeptide phosphorylated antigens termed TUBag1-4. Among these latter, TUBag4 has already been biochemically characterized as a gamma-X derivative of 5'-deoxythymidine triphosphate (Constant, P., Davodeau, F., Peyrat, M. A., Poquet, Y., Puzo, G., Bonneville, M. and Fournié, J.-J., Science 1994. 264: 267). However, despite chemical synthesis of weakly stimulatory nucleotide-containing analogs, these mycobacterial compounds remained the sole nucleotide-containing antigens actually isolated from natural sources. Here, we present the complete isolation of the TUBag3 antigen from Mycobacterium fortuitum and demonstrate that this nonpeptide molecule contains a 5'-UTP nucleotide moiety. On selected V gamma 9/V delta 2 clones, T cell responses can be triggered with nanomolar concentrations of TUBag3. Like crude mycobacterial extracts, this purified nucleotide conjugate elicits a strong polyclonal response of gamma delta PBL from healthy donors. Furthermore, we present evidence that this compound is distinct from the recently synthesized gamma-isopentenyl 5'-UTP, a nucleotide conjugate of isopentenyl pyrophosphate that was found to be stimulatory for human gamma delta T cells (Tanaka, Y., Morita, C.T., Tanaka, Y., Nieves, E., Brenner, M. B. and Bloom, B. R., Nature 1995. 375: 155). Since it appears that both mycobacterial nucleotide antigens are molecules structurally related to peculiar precursors of nucleic acid synthesis, we propose that TUBag-reactive T cells might be specifically devoted to surveillance of proliferating cells.
Poquet
Y
Y
INSERM U395, CHU Purpan, Toulouse, France.
Constant
P
P
Halary
F
F
Peyrat
M A
MA
Gilleron
M
M
Davodeau
F
F
Bonneville
M
M
Fournié
J J
JJ
D000942:Antigens, Bacterial / Q000737:chemistry*; D006801:Humans; D008213:Lymphocyte Activation; D009682:Magnetic Resonance Spectroscopy; D009161:Mycobacterium / Q000276:immunology*; D009711:Nucleotides; D016692:Receptors, Antigen, T-Cell, gamma-delta; D013056:Spectrophotometry, Ultraviolet; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D014544:Uridine Triphosphate / Q000737:chemistry
D000942:Antigens, Bacterial; D009711:Nucleotides; D016692:Receptors, Antigen, T-Cell, gamma-delta; D014544:Uridine Triphosphate