Changing patterns of cell surface mono (ADP-ribosyl) transferase antigen ART2.2 on resting versus cytopathically-activated T cells in NOD/Lt mice.
OBJECTIVE
ART2.2 is a mouse T-cell surface ectoenzyme [mono (ADP-ribosyl) transferase] shed upon strong activation. We analysed temporal changes in ART2.2 expression in unmanipulated and cyclophosphamide-treated NOD/Lt mice compared with diabetes-resistant control strains. We used NAD, the ART2.2 substrate, to test whether ART-mediated ADP-ribosylation could retard diabetogenic activation of islet-reactive T cells in vitro.


METHODS
ART2.2 and CD38, another NAD-utilizing enzyme, were measured by flow cytometry. ADP-ribosylation from ethano-NAD was followed by flow cytometry using a reagent specific for etheno-ADP ribose.


RESULTS
Although mature NOD CD4 + and C D8 + T cells expressed ART2.2, this expression was delayed in young NOD mice when compared with control strains. This ontological delay at 3 weeks of age correlated with an early burst of CD25 expression unique to NOD splenic T cells. This pattern was reproduced in cyclophosphamide-accelerated diabetes in young NOD/Lt males, wherein a retarded repopulation of ART2.2 T cells in spleen and islets correlated with development of heavy insulitis and diabetes. NAD inhibited anti-CD3 induced activation of splenic T cells in vitro and also retarded killing of beta-cell targets by NOD islet-reactive CD8 effectors in vitro at concentrations equal to or greater than 1 micromol/l. Evidence suggested that CD38 on B lymphocytes competes with ART2.2 for substrate needed by B lymphocytes for ADP ribosylation.


CONCLUSIONS
ART2.2 on T cells may not simply mark the resting state, but could also contribute to it via ADP-ribosylation.
Ablamunits
V
V
The Jackson Laboratory, Bar Harbor, Maine 04609, USA.
Bridgett
M
M
Duffy
T
T
Haag
F
F
Nissen
M
M
Koch-Nolte
F
F
Leiter
H
H
D036002:ADP Ribose Transferases / Q000378:metabolism*; D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D000375:Aging / Q000276:immunology / Q000502:physiology; D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology; D003520:Cyclophosphamide / Q000494:pharmacology; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology* / Q000517:prevention & control; D005434:Flow Cytometry; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D015329:Gene Rearrangement, T-Lymphocyte; D007515:Islets of Langerhans / Q000201:enzymology; D008213:Lymphocyte Activation; D008297:Male; D008562:Membrane Glycoproteins; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D016688:Mice, Inbred NOD; D008815:Mice, Inbred Strains; D008822:Mice, Transgenic; D009244:NAD+ Nucleosidase / Q000378:metabolism; D013154:Spleen / Q000201:enzymology; D013601:T-Lymphocytes / Q000201:enzymology* / Q000276:immunology
D015703:Antigens, CD; D000943:Antigens, Differentiation; D008562:Membrane Glycoproteins; D003520:Cyclophosphamide; D036002:ADP Ribose Transferases; D036541:ADP-ribosyl Cyclase; C498155:Cd38 protein, mouse; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1