Biomedical subjects

Ake Lernmark

Publications and source records attributed to Ake Lernmark.

At least 37 records · Page 2Linked to original sources

PubMed2004

Involvement of eotaxin, eosinophils, and pancreatic predisposition in development of type 1 diabetes mellitus in the BioBreeding rat.

Allergy and autoimmunity are both examples of deregulated immunity characterized by inflammation and injury of targeted tissues that have until recently been considered disparate disease processes. However, recent findings have implicated mast cells, in coordination with granulocytes and other immune effector cells, in the pathology of these two disorders. The BioBreeding (BB) DRlyp/lyp rat develops an autoimmune insulin-dependent diabetes similar to human type 1 diabetes mellitus (T1DM), whereas the BBDR+/+ rat does not. To better understand immune processes during development of T1DM, gene expression profiling at day (d) 40 (before insulitis) and d65 (before disease onset) was conducted on pancreatic lymph nodes of DRlyp/lyp, DR+/+, and Wistar-Furth (WF) rats. The eosinophil-recruiting chemokine, eotaxin, and the high-affinity IgE receptor (FcepsilonRI) were up-regulated >5-fold in d65 DRlyp/lyp vs d65 DR+/+ pancreatic lymph nodes by microarray (p < 0.05) and quantitative RT-PCR studies (p < 0.05). DR+/+, WF, and d40 DRlyp/lyp animals possessed normal pancreatic histology; however, d65 DRlyp/lyp animals possessed eosinophilic insulitis. Therefore, immunohistochemistry for pancreatic eotaxin expression was conducted, revealing positive staining of d65 DRlyp/lyp islets. Islets of d65 DR+/+ rats also stained positively, consistent with underlying diabetic predisposition in the BB lineage, whereas WF islets did not. Other differentially expressed transcripts included those associated with eosinophils, mast cells, and lymphocytes. These data support an important role for these inflammatory mediators in BB rat T1DM and suggest that the lymphopenia due to the Ian5/(lyp) mutation may result in a deregulation of cells involved in insulitis and beta cell destruction.

Animals↗

PubMed2004

A high prevalence of organ-specific autoimmunity in patients with bipolar disorder.

BACKGROUND: In a previous study, we reported an increased prevalence of thyroperoxidase antibodies (TPOA) in patients with bipolar disorder. Here we report the prevalence of other organ-specific autoantibodies: H/K adenosine triphosphatase (ATPA), glutamic acid decarboxylase-65 (GAD65A), and GAD-67 (GAD67A). METHODS: ATPA, GAD65A, and GAD67A were determined (via a commercially available enzyme linked immunosorbent assay for ATPA, and a standardized radio immunoassays for GAD65A and GAD67A)in the sera of 239 patients with DSM-IV bipolar disorder, in 74 patients with DSM-IV schizophrenia, and in 220 healthy control subjects. RESULTS: The positivity prevalences for ATPA and GAD65A (but not GAD67A) were elevated in bipolar patients compared with those in healthy control subjects (11.7 vs. 6.1% and 11.3 vs. 2.6% respectively; p <.05). Schizophrenia patients did not show such statistically higher prevalence. The elevated prevalence of ATPA and GAD65A in bipolar disorder was associated with neither rapid cycling nor the use of lithium. Interestingly, the presence of GAD65A (and not that of TPOA and ATPA) tended to be associated with the activity of bipolar disorder. The level of TPOA was negatively correlated with the serum level of sIL-2R, a measure of T cell activation. CONCLUSION: Bipolar disorder is associated with organ-specific autoimmunity to the antigens TPO, H/K ATPase, and GAD65.

Autoantibodies↗

PubMed2004

Transgenic rescue demonstrates involvement of the Ian5 gene in T cell development in the rat.

A single point mutation in a novel immune-associated nucleotide gene 5 (Ian5) coincides with severe T cell lymphopenia in BB rats. We used a transgenic rescue approach in lymphopenic BB-derived congenic F344.lyp/lyp rats to determine whether this mutation is responsible for lymphopenia and to establish the functional importance of this novel gene. A 150-kb P1 artificial chromosome (PAC) transgene harboring a wild-type allele of the rat Ian5 gene restored Ian5 transcript and protein levels, completely rescuing the T cell lymphopenia in the F344.lyp/lyp rats. This successful complementation provides direct functional evidence that the Ian5 gene product is essential for maintaining normal T cell levels. It also demonstrates that transgenic rescue in the rat is a practical and definitive method for revealing the function of a novel gene.

Animals↗

PubMed2004

Development of glutamic acid decarboxylase 65 (GAD65) autoantibody assay using biotin-GAD65 fusion protein.

We evaluated a biotin-glutamic acid decarboxylase 65 (GAD65)-based enzyme-linked immunosorbent assay (B-ELISA) to detect GAD65 autoantibodies (GAD65Ab) in 78 sera from individuals with newly diagnosed type 1 diabetes. The GAD65Ab index of patients with type 1 diabetes (mean value of GAD65Ab index of 1.891) was significantly higher than those in 50 sera from healthy control group (mean value of 0.068). The intra- and inter-assay coefficients of variation (CV) were calculated to be 1.042 and 10.703%, respectively. The specificity of the B-GAD65 ELISA was comparable to the standard radioimmunoassay (RIA) which is routinely used in the laboratory. We describe the optimal conditions of the binding kinetics from each assay-step for the detection of GAD65Ab using the WHO standard serum 97/550 as a model autoantibody serum. We concluded that incubation times of 15, 90, and 90 min for step 1 (pre-incubation of Biotin14-GAD65 with serum), step 2 (binding the Ab/Ag complex to NeutrAvidin plate), and step 3 (incubation with HRPO-anti-human IgG), respectively, along with human serum dilutions of 1:50, would provide an optimal assay signal within a relatively short timeframe.

Autoantigens↗

PubMed2004

Systematic screening of potential beta-cell imaging agents.

The beta-cell loss seen in diabetes mellitus could be monitored clinically by positron emission tomography (PET) if imaging agents were sufficiently specific for beta-cells to overcome the high ratio of non-beta-cell to beta-cell tissue in pancreas. In this report, we present a screening assay for identifying beta-cell-specific compounds that is based on the relative accumulation and retention by islet, INS-1, and exocrine (PANC-1) cells of candidate molecules. Molecules thought to have a high affinity for beta-cells were tested and included glibenclamide, tolbutamide, serotonin, L-DOPA, dopamine, nicotinamide, fluorodeoxyglucose, and fluorodithizone. Glibenclamide and fluorodithizone were the most specific, but the specificity ratios fell well below those needed to attain robust signal to background ratio as a PET imaging agent for quantifying beta-cell mass. In vivo tests of the biodistribution of glibenclamide and fluorodithizone in rats indicated that the compounds were not specifically associated with pancreas, bearing out the predictions of the in vitro screen.

Animals↗

PubMed2004

Non-invasive imaging of beta cell mass: a quantitative analysis.

BACKGROUND: Currently there are major efforts to develop strategies for the in vivo imaging of pancreatic beta cell mass as a clinical and investigational tool for detecting and tracking the loss of beta cells that underlies the progression of Type I diabetes. However, beta cells constitute only about 1% of pancreatic mass and are distributed throughout the pancreas within tiny islets of Langerhans that are each less than the spatial resolution of non-invasive imaging technologies. METHODS: To estimate the requisite binding characteristics of a candidate beta cell imaging agent, calculations of the beta cell contribution to a positron emission tomography signal were made using simple equations. These were based on the relative population of beta cells and non-beta cells within the pancreas and surrounding tissue and an equation describing equilibrium ligand binding. RESULTS: The calculations show that two criteria must be met: (1) The low-volume fraction of beta cells within the exocrine pancreas (about 1:100) requires that beta cells retain labeled imaging agents at least 1,000-fold more strongly than exocrine cells. (2) Agents that label cell surface receptors, even if beta cell-specific, must do so at a high enough level so that the imaging signal arising from unbound label retained in extracellular spaces must not overwhelm signals from labeled beta cells. CONCLUSIONS: The limits developed here can serve as criteria for identifying candidate imaging agents for the in vivo imaging of beta cell mass, thereby avoiding expensive preclinical development using compounds that have no chance of success.

Diabetes Mellitus, Type 1↗

PubMed2004

Epitope-restricted 65-kilodalton glutamic acid decarboxylase autoantibodies among new-onset Sardinian type 2 diabetes patients define phenotypes of autoimmune diabetes.

The 65-kDa glutamic acid decarboxylase (GAD65) autoantibodies (GAD65Abs), commonly found in type 1 diabetes mellitus (T1DM) patients, are also found at lower frequencies in type 2 diabetes mellitus (T2DM) patients. GAD65Abs in T1DM patients are epitope specific, in contrast to those found in other GAD65Ab-positive individuals, including T2DM patients. Our aim was to assess whether epitope-specific GAD65Abs, or the additional presence of islet antigen 2 (IA-2) autoantibodies, better define T1DM phenotypes among T2DM patients. GAD65 and IA-2 autoantibodies were analyzed in 1436 Sardinian subjects classified with T2DM and in 384 nondiabetic patient controls. Autoantibody binding specificity to the N-terminal, middle (M), and C-terminal (C) portions of the GAD65 molecule was evaluated. Among the T2DM patients, 5.1% had GAD65 (P < 0.001) and 2.4% had IA-2 autoantibodies, compared with 1.3 and 1.6%, respectively, among the controls. GAD65Ab-positive T2DM patients with M+C (epitope-specific) reactivity were found to have the lowest body mass index (P < 0.001), followed by GAD65Ab/IA-2Ab-positive patients (P < 0.01), and non-M+C-reactive (non-epitope-specific) patients (P < 0.02). In GAD65Ab-positive T2DM patients, c-peptide levels were lower in M+C-reactive compared with non-M+C-reactive patients. Sardinian T2DM patients with M+C-predominant GAD65Ab reactivity have clinical features more similar to those of T1DM patients. Thus, GAD65Ab epitope analysis may help to define T1DM phenotypes among newly diagnosed GAD65Ab-positive patients classified with T2DM.

Adult↗

PubMed2003

GAD2 on chromosome 10p12 is a candidate gene for human obesity.

The gene GAD2 encoding the glutamic acid decarboxylase enzyme (GAD65) is a positional candidate gene for obesity on Chromosome 10p11-12, a susceptibility locus for morbid obesity in four independent ethnic populations. GAD65 catalyzes the formation of gamma-aminobutyric acid (GABA), which interacts with neuropeptide Y in the paraventricular nucleus to contribute to stimulate food intake. A case-control study (575 morbidly obese and 646 control subjects) analyzing GAD2 variants identified both a protective haplotype, including the most frequent alleles of single nucleotide polymorphisms (SNPs) +61450 C>A and +83897 T>A (OR = 0.81, 95% CI [0.681-0.972], p = 0.0049) and an at-risk SNP (-243 A>G) for morbid obesity (OR = 1.3, 95% CI [1.053-1.585], p = 0.014). Furthermore, familial-based analyses confirmed the association with the obesity of SNP +61450 C>A and +83897 T>A haplotype (chi(2) = 7.637, p = 0.02). In the murine insulinoma cell line betaTC3, the G at-risk allele of SNP -243 A>G increased six times GAD2 promoter activity (p < 0.0001) and induced a 6-fold higher affinity for nuclear extracts. The -243 A>G SNP was associated with higher hunger scores (p = 0.007) and disinhibition scores (p = 0.028), as assessed by the Stunkard Three-Factor Eating Questionnaire. As GAD2 is highly expressed in pancreatic beta cells, we analyzed GAD65 antibody level as a marker of beta-cell activity and of insulin secretion. In the control group, -243 A>G, +61450 C>A, and +83897 T>A SNPs were associated with lower GAD65 autoantibody levels (p values of 0.003, 0.047, and 0.006, respectively). SNP +83897 T>A was associated with lower fasting insulin and insulin secretion, as assessed by the HOMA-B% homeostasis model of beta-cell function (p = 0.009 and 0.01, respectively). These data support the hypothesis of the orexigenic effect of GABA in humans and of a contribution of genes involved in GABA metabolism in the modulation of food intake and in the development of morbid obesity.

Adult↗

PubMed2003

Molecular engineering of biotin-glutamic acid decarboxylase 65 fusion protein (Biotin-GAD65) for non-radioactive GAD65 antibody assay.

We constructed biotinylated fusion proteins that linked to three detection tags to GAD65 at the N-terminus, and expressed them in an E. coli expression system. The Biotin14-GAD65 protein exhibited the strongest binding to both the GAD65 antibody and the streptavidin among the three constructs. We describe the optimal conditions using a Biotin14-GAD65-based immunoassay for the detection of GAD65 antibody.

Antibodies↗

PubMed2003

Impaired glucagon response to sympathetic nerve stimulation in the BB diabetic rat: effect of early sympathetic islet neuropathy.

We investigated the functional impact of a recently described islet-specific loss of sympathetic nerves that occurs soon after the autoimmune destruction of beta-cells in the BB diabetic rat (35). We found that the portal venous (PV) glucagon response to sympathetic nerve stimulation (SNS) was markedly impaired in newly diabetic BB rats (BB D). We next found a normal glucagon response to intravenous epinephrine in BB D, eliminating the possibility of a generalized secretory defect of the BB D alpha-cell as the mediator of the impaired glucagon response to SNS. We then sought to determine whether the glucagon impairment to SNS in BB D was due solely to their loss of islet sympathetic nerve terminals or whether other effects of autoimmune diabetes contributed. We therefore reproduced, in nondiabetic Wistar rats, an islet nerve terminal loss similar to that in BB D with systemic administration of the sympathetic neurotoxin 6-hydroxydopamine. The impairment of the glucagon response to SNS in these chemically denervated, nondiabetic rats was similar to that in the spontaneously denervated BB D. We conclude that the early sympathetic islet neuropathy of BB D causes a functional defect of the sympathetic pathway to the alpha-cell that can, by itself, account for the impaired glucagon response to postganglionic SNS.

Animals↗

PubMed2003

Association between the transmembrane region polymorphism of MHC class I chain related gene-A and type 1 diabetes mellitus in Sweden.

Major histocompatibility complex (MHC) class I chain related gene-A (MIC-A) is associated with type 1 diabetes mellitus (T1DM) in other populations. We tested the association of MIC-A gene polymorphism with T1DM in Swedish Caucasians; if it has an age-dependent association; and if the association has an effect on gender. We studied 635 T1DM patients and 503 matched controls in the age group of 0-35 years old. MIC-A5 was significantly increased in T1DM compared with controls (odds ratio [OR] =1.81, p(c) < 0.0005). Logistic regression analysis revealed MIC-A5 association was independent of HLA. MIC-A5 with DR4-DQ8 or MIC-A5 with DR3-DQ2 gave higher OR than the OR obtained with either of them alone (OR = 1.81, 7.1, and 3.6, respectively). MIC-A5 was positively (OR = 2.48, p(c) < 0.0005) and MIC-A6 negatively associated (OR = 0.61, p(c) = 0.035) with the disease in < or = 20 years of age. The negative association of MIC-A6 in young onset was confirmed by logistic regression analysis. MIC-A5 was associated with the disease in males (OR = 2.05, p(c) = 0.0005). MIC-A6 conferred protection (OR = 0.098, p(c) = 0.032) in females heterozygous for DR3/DR4. In conclusion, MIC-A5 is associated with T1DM; the association was higher in individuals < or = 20 years old; and negative association of MIC-A6 was stronger in younger onset patients than in older onset patients.

Adolescent↗

PubMed2003

Genetic dissection of lymphopenia from autoimmunity by introgression of mutated Ian5 gene onto the F344 rat.

Peripheral T cell lymphopenia (lyp) in the BioBreeding (BB) rat is linked to a frameshift mutation in Ian5, a member of the Immune Associated Nucleotide (Ian) gene family on rat chromosome 4. This lymphopenia leads to type 1 (insulin-dependent) diabetes mellitus (T1DM) at rates up to 100% when combined with the BB rat MHC RT1 u/u genotype. In order, to better study the lymphopenia phenotype without possible confounding effects of diabetes or other autoimmune disease, we generated congenic F344.lyp rats by introgression of lyp on diabetes-resistant MHC RT1 lv1/lv1 F344 rats. Analysis of thymic CD4 and CD8 T lymphocytes revealed no difference in the percentage of CD4(-)CD8(+)and CD4(+)CD8(-)subsets in lyp/lyp compared to +/+ F344 rats. The same subsets was however dramatically reduced in blood (P=0.005), spleen (P=0.019) and mesenteric lymph nodes (MLN) (P<0.0001). Compared to F344 +/+ rats double positive CD4(+)CD8(+)T cells were increased only in lyp/lyp spleen (P=0.034) while double negative CD4(-)CD8(-)were increased in thymus (P=0.033), spleen (P=0.012), MLN (P<0.0001), and peripheral blood (P<0.0001). There were no signs of inflammatory lesions in organs and tissues in F344.lyp/lyp rats examined at 120 days of age or older. We thus conclude that the lymphopenia phenotype was reconstituted by introgression of lyp on to F344 rats without subsequent development of organ-specific autoimmunity. The congenic F344.lyp rat should prove useful to dissect the mechanisms by which the Ian5 frameshift mutation affects T cell selection, differentiation and maturation without organ-specific autoimmunity.

Animals↗

PubMed2003

Bead injection ELISA for the determination of antibodies implicated in type 1 diabetes mellitus.

This work introduces a novel analytical method for the detection and study of GAD65 autoantibodies, which have been implicated in the onset of type 1 diabetes. There is a clinical need for a rapid and automated assay for GAD65 autoantibodies. Therefore, this method was designed to exploit the advantages of bead injection (BI) analysis for enzyme-linked immunosorbent assays (ELISA). BI ELISA is a microscale technique that uses enzyme labeled secondary antibodies to detect the capture of target antibodies on immobilized antigen in the flow cell of the lab-on-valve (LOV) manifold. A detection limit of 20 ng mL(-1) of GAD65 monoclonal antibody 144 compares favorably with the sensitivity and precision of a standard ELISA currently employed to detect GAD65 autoantibodies. Compared to the standard ELISA protocol, BI ELISA offers a significantly reduced assay time and complete automation of solution handling and detection.

Autoanalysis↗

PubMed2003

Islet cell autoantibodies in cord blood from children with blood group incompatibility or hyperbilirubinemia.

Blood group incompatibility is a risk factor for type 1 diabetes. Our aim was to test the hypothesis that islet cell autoantibodies, as markers for beta cell autoimmunity, are increased in cord blood from newborns with a diagnosis of blood group incompatibility. Using the diagnosis register of the Malmö University Hospital we obtained cord blood from 151 children with ABO immunization, 311 children with hyperbilirubinemia and a control group of 320 other children born during the same time period. The cord blood samples were analyzed for islet cell antibodies (ICA) by indirect immunofluorescence and autoantibodies against the Islet Cell Antigen-2 (IA-2Ab) and the 65 kDa isoform of glutamic acid decarboxylase (GAD65Ab) by standard radioligand binding assays. The prevalence of ICA was increased compared to controls (0.6%) not only in children with ABO immunization (4.0%, p = 0.02), but also in newborn children with hyperbilirubinemia (4.2%, p = 0.003). The prevalence of IA2Ab, but not of GAD65Ab, was increased in children with ABO immunization (3.3%) compared to the hyperbilirubinemia group without incompatibility (0.6%, p = 0.04), or the controls (0.3%, p = 0.02). Our findings that hyperbilirubinemia is associated with an increased prevalence of ICA, and blood group incompatibility with both ICA and IA-2, suggests that intra-uterine factors may be associated with islet cell autoimmunity.

ABO Blood-Group System↗

PubMed2003

Islet autoantibodies in cord blood from patients who developed type 1 diabetes mellitus at 15-30 years of age.

Islet cell autoantibodies are early markers for type 1 diabetes. The aim of this study was to determine whether islet autoantibodies were present at birth in young adults who developed type 1 diabetes at 15-30 years of age. Cord blood sera from 30 patients who developed type 1 diabetes between 15 and 25 years of age and sera from 320 randomly selected control children were tested for islet cell antibodies (ICA) by indirect immunofluorescence and autoantibodies against the 65 kD isoform of glutamic acid decarboxylase (GADA), islet cell antigen-2 (IA-2A) and insulin (IAA) by radiobinding assays. The young adults who developed type 1 diabetes did not differ from controls in the cord blood prevalence of any of the four islet autoantibodies. This is in contrast to our previous findings that children who developed type 1 diabetes below 15 years of age had an increased prevalence of cord blood islet autoantibodies. Our present data suggest that, in contrast to children, pre- and perinatal risk factors are less likely to be involved in the development of type 1 diabetes in young adults.

Adolescent↗

PubMed2003

Tissue transglutaminase immunoglobulin isotypes in children with untreated and treated celiac disease.

OBJECTIVES: Tissue transglutaminase (tTG) autoantibodies are serologic markers for celiac disease (CD). The aim was to determine the diagnostic sensitivity and specificity of different immunoglobulin isotypes against tTG. METHODS: Immunoglobulin A (IgA)-tTG, IgG-tTG, and IgG1-tTG were measured in radioligand binding assays in 67 children with untreated and 89 children with treated CD and compared with 48 biopsy controls. IgM-tTG was measured in children with untreated CD and in biopsy controls. IgA endomysial autoantibodies (EMA) were analyzed in all children using an immunofluorescence method. RESULTS: The sensitivity of IgA-tTG and IgG-tTG was 85.1% (57 of 67) and 83.6% (56 of 67), respectively, which both increased to 93.8% (45 of 48) in children diagnosed at age 2 years or older. Both had a specificity of 93.8% (45 of 48). IgA-EMA had a sensitivity of 80.6% (54 of 67) and a specificity of 91.7% (44 of 48). In treated CD, IgA-tTG and IgG-tTG were detected in 21.3% (19 of 89) and in 14.6% (13 of 89), respectively, despite negative EMA titers. IgG1-tTG was correlated to age (r = -0.47, P = 0.0005) and detected in 50.7% (34 of 67) with untreated CD compared with 11.2% (10 of 89) with treated CD and with 4.2% (2 of 48) of biopsy controls ( P < 0.0001, respectively). IgM-tTG was detected in 1.5% (1 of 67) with untreated CD and in none of biopsy controls. CONCLUSION: IgA-tTG and IgG-tTG analyzed in radioligand binding assays are equivalent to IgA-EMA as screening tests for CD during childhood, but an intestinal biopsy is still the method of choice to establish the diagnosis. Although IgG1-tTG was more common at young age of diagnosis, both IgG1-tTG and IgM-tTG had low specificity and sensitivity and may not be useful as screening tests for CD.

Adolescent↗

PubMed2003

Type 1 diabetes in Swedish bank voles (Clethrionomys glareolus): signs of disease in both colonized and wild cyclic populations at peak density.

Colonized bank voles (Clethrionomys glareolus) originating from Sweden developed type 1 diabetes. Animals became polydipsic, glucosuric, and hyperglycemic and gradually developed a lethal ketoacidosis. Pancreas in animals with end-stage disease showed total destruction of islet cells. Interestingly, also a high proportion of wild bank voles in cyclic populations that were trapped at (or close to) the cyclic population density peak frequently showed high blood glucose levels and pathological glucose tolerance test. Extensive islet destruction was not seen in wild bank voles at the time of capture, but did develop in some of the animals over a time period of two months. Diabetes in both colonized and wild bank voles was associated with Ljungan virus (LV). LV could be isolated from the pancreas of diabetic bank voles and antigen detected at the site of tissue damage by immunohistochemistry. In addition, picornavirus-like particles were visualized in the islets of diabetic voles using thin-section transmission electron microscopy.

Animals↗

PubMed2003

Unique epitopes of glutamic acid decarboxylase autoantibodies in slowly progressive type 1 diabetes.

Disease-specific epitope profiles of glutamic acid decarboxylase (GAD)65 autoantibodies (GAD65Ab) were studied in slowly progressive type 1 (insulin-dependent) diabetes mellitus (SPIDDM) and acute onset type 1 (insulin-dependent) diabetes mellitus (AIDDM) using seven kinds of GAD65/67 chimeric molecules. Sera obtained from Japanese SPIDDM (n = 17) and AIDDM (n = 46) patients followed prospectively were analyzed by immunoprecipitation, ELISA, and Western blotting. GAD65Ab in all SPIDDM samples reacted specifically with an N-terminal linear epitope located on the membrane anchoring domain between amino acids 17-51 and C-terminal conformational epitope between amino acids 443-585 of GAD65. The binding of GAD65Ab with N-terminal 83 residues in SPIDDM inversely correlated with the period in which insulin was not required. GAD65Ab in AIDDM did not react with N-terminal epitope located between amino acids 1-83, irrespective of the titer of GAD65Ab. A novel epitope of GAD65Ab in AIDDM residing between amino acids 244-360 was identified in 17% (8 of 46) of patients whose age of onset was younger than other AIDDM patients. In conclusion, GADAb in SPIDDM has unique N-terminal linear epitopes that are located on the anchoring domain of GAD65 molecules. Association is suggested between GAD65Ab targeted to this region and slowly progressive beta-cell failure in SPIDDM.

Autoantibodies↗