Autoimmunity to tetraspanin-7 in type 1 diabetes

Type 1 diabetes is an autoimmune disease whereby components of insulin-secreting pancreatic beta cells are targeted by the adaptive immune system leading to the destruction of these cells and insulin deficiency. There is much interest in the development of antigen-specific immune intervention as an approach to prevent disease development in individuals identified as being at risk of disease. It is now recognised that there are multiple targets of the autoimmune response in type 1 diabetes, the most recently identified being a member of the tetraspanin family, tetraspanin-7. The heterogeneity of autoimmune responses to different target antigens complicates the assessment of diabetes risk by the detection of autoantibodies, as well as creating challenges for the design of strategies to intervene in the immune response to these autoantigens. This review describes the discovery of tetraspanin-7 as a target of autoantibodies in type 1 diabetes and how the detection of autoantibodies to the protein provides a valuable marker for future loss of pancreatic beta-cell function

Site occupancy and electric-field induced strain response of Er-doped (Bi0.4Na0.4Sr0.2)TiO3 ceramics

© 2018 Elsevier B.V. Er-doped (Bi0.4Na0.4Sr0.2)TiO3 powders were prepared by solid state reactions according to A-site donor (Bi0.4-x/3Na0.4-x/3Sr0.2-x/3Erx)TiO3 (x = 0.0.015 and 0.02) and B-site acceptor (Bi0.4Na0.4Sr0.2)Ti1-yEryO3 (y = 0, 0.015 and 0.02) substitutional doping mechanisms. In both cases, room-temperature X-ray diffraction analyses revealed a decrease of the unit cell volume with increasing Er contents, suggesting A-site occupancy to be thermodynamically more favourable. Over the 25–175 °C temperature range, A-site doped ceramics, in particular x = 0.015, showed enhanced thermal stability of the maximum achievable electric-field induced strain. Importantly, this minor doping level also reduced dielectric loss at high temperature and led to a transition from non-ergodic to ergodic relaxor behaviour. These results may further motivate the study of the impact of other minor dopants in this family of Pb-free piezoceramics

Autoantibodies against cytochrome P450 side-chain cleavage enzyme in dogs (Canis lupus familiaris) affected with hypoadrenocorticism (Addison’s Disease)

Canine hypoadrenocorticism likely arises from immune-mediated destruction of adrenocortical tissue, leading to glucocorticoid and mineralocorticoid deficiency. In humans with autoimmune Addison's disease (AAD) or autoimmune polyendocrine syndrome (APS), circulating autoantibodies have been demonstrated against enzymes associated with adrenal steroid synthesis. The current study investigates autoantibodies against steroid synthesis enzymes in dogs with spontaneous hypoadrenocorticism. Coding regions of canine CYP21A2 (21-hydroxylase; 21-OH), CYP17A1 (17-hydroxylase; 17-OH), CYP11A1 (P450 side-chain cleavage enzyme; P450scc) and HSD3B2 (3β hydroxysteroid dehydrogenase; 3βHSD) were amplified, cloned and expressed as 35S-methionine radiolabelled recombinant protein. In a pilot study, serum samples from 20 dogs with hypoadrenocorticism and four unaffected control dogs were screened by radio-immunoprecipitation assay. There was no evidence of reactivity against 21-OH, 17-OH or 3βHSD, but five dogs with hypoadrenocorticism showed immunoreactivity to P450scc compared with controls. Serum samples were subsequently obtained from 213 dogs diagnosed with hypoadrenocorticism and 110 dogs from a hospital control population. Thirty control dogs were randomly selected to establish a threshold for antibody positivity (mean + 3 × standard deviation). Dogs with hypoadrenocorticism were more likely to be P450scc autoantibody positive than hospital controls (24% vs. 1.2%, respectively; p = 0.0016). Sex was significantly associated with the presence of P450scc autoantibodies in the case population, with 30% of females testing positive compared with 17% of males (p = 0.037). Significant associations with breed (p = 0.015) and DLA-type (DQA1*006:01 allele; p = 0.017) were also found. This cross-sectional study indicates that P450scc autoantibodies are present in a proportion of dogs affected with hypoadrenocorticism

Using a conceptual framework during learning attenuates the loss of expert-type knowledge structure

BACKGROUND: During evolution from novice to expert, knowledge structure develops into an abridged network organized around pathophysiological concepts. The objectives of this study were to examine the change in knowledge structure in medical students in one year and to investigate the association between the use of a conceptual framework (diagnostic scheme) and long-term knowledge structure. METHODS: Medical students' knowledge structure of metabolic alkalosis was studied after instruction and one year later using concept-sorting. Knowledge structure was labeled 'expert-type' if students shared ≥ 2 concepts with experts and 'novice-type' if they shared < 2 concepts. Conditional logistic regression was used to study the association between short-term knowledge structure, the use of a diagnostic scheme and long-term knowledge structure. RESULTS: Thirty-four medical students completed the concept-sorting task on both occasions. Twenty-four used a diagnostic scheme for metabolic alkalosis. Short-term knowledge structure was not a correlate of long-term knowledge structure, whereas use of a diagnostic scheme was associated with increased odds of expert-type long-term knowledge structure (odds ratio 12.6 [1.4, 116.0], p = 0.02). There was an interaction between short-term knowledge structure and the use of a diagnostic scheme. In the group who did not use a diagnostic scheme the number of students changing from expert-type to novice-type was greater than vice versa (p = 0.046). There was no significant change in the group that used the diagnostic scheme (p = 0.6). CONCLUSION: The use of a diagnostic scheme by students may attenuate the loss of expert-type knowledge structure

A sweeter way of teaching health and safety

The underpinning educational theory for practical work is that of experimental learning or 'learning by and through doing'. Hands-on practical work promotes learning as it provides students with an opportunity to put theory into practice. There are many hazards with practical work, each with an associated risk that students will encounter while they are working in the laboratory and, therefore, adequate instruction should be given before students carry out any practical work. Getting students to engage with this in the past has been difficult due to the dryness of the material. Here we show how every students sweet tooth can be used to teach them risk assessment, experimental design and embedding health and safety as part of their scientific culture

Isolation of human monoclonal autoantibodies derived from pancreatic lymph node and peripheral blood B cells of islet autoantibody-positive patients

Aims/hypothesis Autoantibodies against pancreatic islets and infections by enteroviruses are associated with type 1 diabetes, but the specificity of immune responses within the type 1 diabetic pancreas is poorly characterised. We investigated whether pancreatic lymph nodes could provide a source of antigen-specific B cells for analysis of immune responses within the (pre)diabetic pancreas. Methods Human IgG antibodies were cloned from single B lymphocytes sorted from pancreatic lymph node cells of three organ donors positive for islet autoantibodies, and from the peripheral blood of a patient with type 1 diabetes. Antibodies to insulinoma-associated antigen 2 (IA-2), GAD65, zinc trans- porter 8 (ZnT8) and Coxsackie B virus proteins were assayed by immunoprecipitation and by immunofluorescence on pan- creatic sections. Results Human IgG antibodies (863) were successfully cloned and produced from 4,092 single B cells from lymph nodes and peripheral blood. Reactivity to the protein tyrosine phosphatase domain of the IA-2 autoantigen was detected in two cloned antibodies: one derived from a pancreatic lymph node and one from peripheral blood. Epitopes for these two antibodies were similar to each other and to those for circulat- ing antibodies in type 1 diabetes. The remaining 861 antibod- ies were negative for reactivity to IA-2, GAD65 or ZnT8 by both assays tested. Reactivity to a Coxsackie viral protein 2 was detected in one antibody derived from a peripheral blood B cell, but not from lymph nodes. Conclusions/interpretation We show evidence for the infre- quent presence of autoantigen-specific IgG+ B lymphocytes in the pancreatic-draining lymph nodes of islet autoantibody- positive individuals

Adcyap1r1 Genotype, Posttraumatic Stress Disorder, And Depression Among Women Exposed To Childhood Maltreatment

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97169/1/da22037.pd

Hsp70 enhances presentation of FMDV antigen to bovine CD4+ T cells in vitro

Foot-and-mouth disease virus (FMDV) is the causative agent of a highly contagious acute vesicular disease affecting cloven-hoofed animals, including cattle, sheep and pigs. The current vaccine induces a rapid humoral response, but the duration of the protective antibody response is variable, possibly associated with a variable specific CD4+ T cell response. We investigated the use of heat shock protein 70 (Hsp70) as a molecular chaperone to target viral antigen to the Major Histocompatibility Complex (MHC) class II pathway of antigen presenting cells and generate enhanced MHC II-restricted CD4+ T cell responses in cattle. Monocytes and CD4+ T cells from FMDV vaccinated cattle were stimulated in vitro with complexes of Hsp70 and FMDV peptide, or peptide alone. Hsp70 was found to consistently improve the presentation of a 25-mer FMDV peptide to CD4+ T cells, as measured by T cell proliferation. Complex formation was required for the enhanced effects and Hsp70 alone did not stimulate proliferation. This study provides further evidence that Hsp70:peptide complexes can enhance antigen-specific CD4+ T cell responses in vitro for an important pathogen of livestock

Influence of HLA-DR and -DQ alleles on autoantibody recognition of distinct epitopes within the juxtamembrane domain of the IA-2 autoantigen in type 1 diabetes

Aims/hypothesis: Insulinoma-associated protein 2 (IA-2) is a major target of autoimmunity in type 1 diabetes. When first detected, IA-2-autoantibodies commonly bind epitopes in the juxtamembrane (JM) domain of IA-2 and antibody responses subsequently spread to the tyrosine phosphatase domain. Definition of structures of epitopes in the JM domain, and genetic requirements for autoimmunity to these epitopes, is important for our understanding of initiation and progression of autoimmunity. The aims of this study were to investigate the contribution of individual amino acids in the IA-2 JM domain to antibody binding to these epitopes and the role of HLA genotypes in determining epitope specificity. Methods: Regions of the JM domain recognised by autoantibodies were identified by peptide competition and inhibitory effects of alanine substitutions of residues within the JM region. Antibody binding was determined by radioligand binding assays using sera from patients genotyped for HLA-DRB1 and -DQB1 alleles. Results: Patients were categorised into two distinct groups of JM antibody reactivity according to peptide inhibition. Inhibition by substitutions of individual amino acids within the JM domain differed between patients, indicating heterogeneity in epitope recognition. Cluster analysis defined six groups of residues having similar inhibitory effects on antibody binding, with three clusters showing differences in patients affected or unaffected by peptide. One cluster demonstrated significant differences in antibody binding between HLA-DRB1*04 and HLA-DRB1*07 patients and within DRB1*04 individuals; antibody recognition of a second cluster depended on expression of HLA-DQB1*0302. Conclusions/interpretation: The results identify amino acids contributing to distinct epitopes on IA-2, with both HLA-DR and HLA-DQ alleles influencing epitope specificity