title: Extracellular nicotinamide adenine dinucleotide induces t cell apoptosis in vivo and in vitro.
abstract: Incubation of mouse T cells expressing the cell surface enzyme ADP ribosyltransferase with nicotinamide adenine dinucleotide (NAD) had been reported to cause ADP ribosylation of cell surface molecules, inhibition of transmembrane signaling, and suppression of immune responses. In this study, we analyze the reasons for these effects and report that contact of T cells with NAD causes cell death. Naive T cells when incubated with NAD and adoptively transferred into semiallogeneic mice fail to cause graft-vs-host disease, and when injected into syngeneic, T cell-deficient recipients do not reconstitute these mice. Rather, they accumulate in the liver, leading to an increase of apoptotic lymphocytes in this organ. Similar effects are induced by injection of NAD, shown to cause a dramatic increase of apoptotic CD3(+), CD4(+), and CD8(+) cells in the liver. Consistent with this, in vitro incubation of naive T cells with NAD is shown to induce apoptosis. In contrast, no cell death is demonstrable when T cells are activated before incubation with NAD. It is concluded that ecto-NAD, as substrate of ADP ribosyltransferase, acts on naive, but not on activated CD69(+) T cells.
authors.affiliation: Department of Molecular Microbiology and Immunology, University of Southern California/Norris Comprehensive Cancer Center, Keck School of Medicine at University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: Z X
authors.initials: ZX
authors.lastname: Liu
authors.forename: O
authors.initials: O
authors.lastname: Azhipa
authors.forename: S
authors.initials: S
authors.lastname: Okamoto
authors.forename: S
authors.initials: S
authors.lastname: Govindarajan
authors.forename: G
authors.initials: G
authors.lastname: Dennert
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D017209:Apoptosis / Q000187:drug effects*; D001402:B-Lymphocytes / Q000187:drug effects; D006086:Graft vs Host Disease / Q000517:prevention & control; D037181:Lectins, C-Type; D008099:Liver / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D009243:NAD / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000187:drug effects* / Q000502:physiology; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D037181:Lectins, C-Type; D009243:NAD; D000099192:CD69 Antigens