title: P2X7 receptor expression levels determine lethal effects of a purine based danger signal in T lymphocytes.
abstract: Contact of T lymphocytes with nicotinamide adenine dinucleotide (NAD) or ATP causes cell death that requires expression of purinergic receptor P2X(7) (P2X(7)R). T cell subsets differ in their responses to NAD and ATP, which awaits a mechanistic explanation. Here, we show that sensitivity to ATP correlates with P2X(7)R expression levels in CD4 cells, CD8 cells and CD4(+)CD25(+) cells from both C57BL/6 and BALB/c mice. But P2X(7)R ligands do not only induce cell death but also shedding of CD62L. It is shown here that in CD62L(high) T cells, CD62L shedding correlates with low expression of P2X(7)Rs and lower cell death, whereas in CD62L(low) cells P2X(7)R expression and death are higher. The possibility is therefore investigated that P2X(7)Rs induce T cell activation. Experiments show that spontaneous T cell proliferation is somewhat higher in cells expressing P2X(7)Rs, but this effect we suggest is caused by P2X(7)R expression on accessory cells.
authors.affiliation: Department of Molecular Microbiology, USC/Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA.
authors.forename: Fred
authors.initials: F
authors.lastname: Aswad
authors.forename: Gunther
authors.initials: G
authors.lastname: Dennert
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects; D016923:Cell Death; D049109:Cell Proliferation; D004305:Dose-Response Relationship, Drug; D005260:Female; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D019041:L-Selectin / Q000378:metabolism; D008024:Ligands; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D011687:Purines / Q000737:chemistry*; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058486:Receptors, Purinergic P2X7; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*
chemical_list: D053645:Interleukin-2 Receptor alpha Subunit; D008024:Ligands; C546469:P2rx7 protein, mouse; D011687:Purines; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; D019041:L-Selectin; D000255:Adenosine Triphosphate; C030985:purine