title: Differential protection in two transgenic lines of NOD/Lt mice hyperexpressing the autoantigen GAD65 in pancreatic beta-cells.
abstract: Although expressed at very low levels in islets of NOD mice, GAD65 is a candidate islet autoantigen. Two transgenic lines of NOD/Lt mice expressing high levels of human GAD65 from a rat insulin promoter were generated. Transgenes were integrated on proximal chromosome 15 of the A line and on the Y chromosome of the Y line. Transgenic A-line mice were obligate hemizygotes, since homozygous expression resulted in developmental lethality. A twofold higher level of hGAD65 transcripts in A-line islets from young donors was associated with higher GAD protein and enzyme activity levels. Y-line males developed diabetes at a similar rate and incidence as standard NOD/Lt males. In contrast, A-line mice of both sexes exhibited a markedly lowered incidence of diabetes. Insulitis, present in both transgenic lines, developed more slowly in A-line mice and correlated with a reduction in the ratio of gamma-interferon to interleukin-10 transcripts. Splenic leukocytes from young A-line donors transferred diabetes into NOD-scid recipients at a retarded rate compared with those from nontransgenic donors. Further, nontransgenic NOD T-cells transferred diabetes more slowly in NOD-scid recipients that were congenic for A-line transgenes as compared with standard NOD-scid recipients. Primed T-cell responses and spontaneous humoral reactivity to GAD65 failed to distinguish transgenic from nontransgenic mice. Quantitative differences in expression level or insertional mutagenesis are possible mechanisms of protection in the A line.
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine 04609, USA.
authors.forename: M
authors.initials: M
authors.lastname: Bridgett
authors.forename: M
authors.initials: M
authors.lastname: Cetkovic-Cvrlje
authors.forename: R
authors.initials: R
authors.lastname: O'Rourke
authors.forename: Y
authors.initials: Y
authors.lastname: Shi
authors.forename: S
authors.initials: S
authors.lastname: Narayanswami
authors.forename: J
authors.initials: J
authors.lastname: Lambert
authors.forename: V
authors.initials: V
authors.lastname: Ramiya
authors.forename: S
authors.initials: S
authors.lastname: Baekkeskov
authors.forename: E H
authors.initials: EH
authors.lastname: Leiter
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D001323:Autoantibodies / Q000097:blood; D001324:Autoantigens / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics; D016207:Cytokines / Q000235:genetics; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology / Q000235:genetics / Q000276:immunology; D005260:Female; D018628:Gene Dosage; D015870:Gene Expression; D005796:Genes / Q000235:genetics; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015994:Incidence; D007330:Insulin Antibodies / Q000097:blood; D007515:Islets of Langerhans / Q000276:immunology / Q000378:metabolism*; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D008822:Mice, Transgenic; D010182:Pancreatic Diseases / Q000235:genetics / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019076:Transgenes / Q000235:genetics; D014886:Weaning
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D016207:Cytokines; D007330:Insulin Antibodies; D005968:Glutamate Decarboxylase