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In type 1 diabetes a subset of anti-coxsackievirus B4 antibodies recognize autoantigens and induce apoptosis of pancreatic beta cells.

Bason C, Lorini R, Lunardi C, Dolcino M, Giannattasio A, d'Annunzio G, Rigo A, Pedemonte N, Corrocher R, Puccetti A - PLoS ONE (2013)

Bottom Line: Coxsackievirus B infection has been linked to the onset of type 1 diabetes; however its precise role has not been elucidated yet.We identified an immunodominant peptide recognized by the majority of individual patients'sera, that shares homology with Coxsackievirus B4 VP1 protein and with beta-cell specific autoantigens such as phogrin, phosphofructokinase and voltage-gated L-type calcium channels known to regulate beta cell apoptosis.Our results provide evidence that in autoimmune diabetes a subset of anti-Coxsackievirus antibodies are able to induce apoptosis of pancreatic beta cells which is considered the most critical and final step in the development of autoimmune diabetes without which clinical manifestations do not occur.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Section of Internal Medicine, University of Verona, Verona, Italy.

ABSTRACT
Type 1 diabetes is characterized by autoimmune destruction of pancreatic beta cells. The role played by autoantibodies directed against beta cells antigens in the pathogenesis of the disease is still unclear. Coxsackievirus B infection has been linked to the onset of type 1 diabetes; however its precise role has not been elucidated yet. To clarify these issues, we screened a random peptide library with sera obtained from 58 patients with recent onset type 1 diabetes, before insulin therapy. We identified an immunodominant peptide recognized by the majority of individual patients'sera, that shares homology with Coxsackievirus B4 VP1 protein and with beta-cell specific autoantigens such as phogrin, phosphofructokinase and voltage-gated L-type calcium channels known to regulate beta cell apoptosis. Antibodies against the peptide affinity-purified from patients' sera, recognized the viral protein and autoantigens; moreover, such antibodies induced apoptosis of the beta cells upon binding the L-type calcium channels expressed on the beta cell surface, suggesting a calcium dependent mechanism. Our results provide evidence that in autoimmune diabetes a subset of anti-Coxsackievirus antibodies are able to induce apoptosis of pancreatic beta cells which is considered the most critical and final step in the development of autoimmune diabetes without which clinical manifestations do not occur.

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Related in: MedlinePlus

T1DM peptide shares sequence homology with genome poliprotein CXB4 and induces crossreactive antibodies.A, Sequence homology between T1DM peptide and the genome poliprotein CXB4, analyzed by the basic local alignment search tool using the National Center for Biotechnology Information (NCBI) network service. Vertical line = identical amino acids; asterisk = conservative substitutions B, Frequency of the binding of patients’ sera to COXSA peptide and to total viral extract evaluated by ELISA test. C, Direct binding of affinity-purified antibodies against T1DM (black rhombus), COXSA (black square) and irrelevant (black triangle) peptides, to COXSA synthetic peptide. Data represent absorbance at 405 nm (vertical axis) and antibody concentration µg/ml (horizontal axis). D, Binding of affinity-purified antibodies against COXSA peptide is inhibited by T1DM (black rhombus), COXSA (black square) peptides but not by an irrelevant (black triangle) peptide. Data represent inhibition percentage (vertical axis) and the inhibitor concentration µg/ml (horizontal axis). E, Immunoblot analysis of total viral extract revealed with a commercial positive control IgG (Lane 1) or with antibodies affinity purified against the T1DM peptide (Lane 3) or against the COXSA peptide (Lane 4) or against the irrelevant peptide (Lane 2). F, Immunoblot analysis of total viral extract revealed with a commercial positive control IgG (Line 1) or with IgG from a healthy donor’s serum (Lane 2), or with IgG from two different type I diabetes patients’ sera (Lanes 3 and 4). G, Immunoblot analysis of total viral extract revealed with a commercial positive control IgA (Lane 1) or with IgA from a healthy donor’s serum (Lane 2), or with IgA from two different type I diabetes patients’ sera (Lanes 3 and 4).
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pone-0057729-g001: T1DM peptide shares sequence homology with genome poliprotein CXB4 and induces crossreactive antibodies.A, Sequence homology between T1DM peptide and the genome poliprotein CXB4, analyzed by the basic local alignment search tool using the National Center for Biotechnology Information (NCBI) network service. Vertical line = identical amino acids; asterisk = conservative substitutions B, Frequency of the binding of patients’ sera to COXSA peptide and to total viral extract evaluated by ELISA test. C, Direct binding of affinity-purified antibodies against T1DM (black rhombus), COXSA (black square) and irrelevant (black triangle) peptides, to COXSA synthetic peptide. Data represent absorbance at 405 nm (vertical axis) and antibody concentration µg/ml (horizontal axis). D, Binding of affinity-purified antibodies against COXSA peptide is inhibited by T1DM (black rhombus), COXSA (black square) peptides but not by an irrelevant (black triangle) peptide. Data represent inhibition percentage (vertical axis) and the inhibitor concentration µg/ml (horizontal axis). E, Immunoblot analysis of total viral extract revealed with a commercial positive control IgG (Lane 1) or with antibodies affinity purified against the T1DM peptide (Lane 3) or against the COXSA peptide (Lane 4) or against the irrelevant peptide (Lane 2). F, Immunoblot analysis of total viral extract revealed with a commercial positive control IgG (Line 1) or with IgG from a healthy donor’s serum (Lane 2), or with IgG from two different type I diabetes patients’ sera (Lanes 3 and 4). G, Immunoblot analysis of total viral extract revealed with a commercial positive control IgA (Lane 1) or with IgA from a healthy donor’s serum (Lane 2), or with IgA from two different type I diabetes patients’ sera (Lanes 3 and 4).

Mentions: We enrolled fifty-eight patients (35 males, 23 females) aged 0.8–18.7 years (mean age 8.3 years) with recently diagnosed (1–29 days) type 1 diabetes attending the Department of Pediatrics, Giannina Gaslini Institute, Genova. Diagnosis was based on the American Diabetes Association criteria [24]. Patients were tested for anti-glutamic acid decarboxylase (GADA), anti-insulin (IAA) and anti-tyrosine phosphatase-like protein (IA2A) antibodies (Table S1) within 30 days from the diagnosis and before starting insulin therapy. Commercially available kits were used to detect autoantibodies (Radioimmuno-assay CIS Bio International-Schering SA). One hundred age and sex-matched healthy individuals served as controls. Eight subjects with evidence of Coxsackievirus infection and presence of serum antibodies directed against the Coxsackievirus B4 extract were tested for the presence of antibodies against the T1DM and COXSA peptides (Fig. 1B).


In type 1 diabetes a subset of anti-coxsackievirus B4 antibodies recognize autoantigens and induce apoptosis of pancreatic beta cells.

Bason C, Lorini R, Lunardi C, Dolcino M, Giannattasio A, d'Annunzio G, Rigo A, Pedemonte N, Corrocher R, Puccetti A - PLoS ONE (2013)

T1DM peptide shares sequence homology with genome poliprotein CXB4 and induces crossreactive antibodies.A, Sequence homology between T1DM peptide and the genome poliprotein CXB4, analyzed by the basic local alignment search tool using the National Center for Biotechnology Information (NCBI) network service. Vertical line = identical amino acids; asterisk = conservative substitutions B, Frequency of the binding of patients’ sera to COXSA peptide and to total viral extract evaluated by ELISA test. C, Direct binding of affinity-purified antibodies against T1DM (black rhombus), COXSA (black square) and irrelevant (black triangle) peptides, to COXSA synthetic peptide. Data represent absorbance at 405 nm (vertical axis) and antibody concentration µg/ml (horizontal axis). D, Binding of affinity-purified antibodies against COXSA peptide is inhibited by T1DM (black rhombus), COXSA (black square) peptides but not by an irrelevant (black triangle) peptide. Data represent inhibition percentage (vertical axis) and the inhibitor concentration µg/ml (horizontal axis). E, Immunoblot analysis of total viral extract revealed with a commercial positive control IgG (Lane 1) or with antibodies affinity purified against the T1DM peptide (Lane 3) or against the COXSA peptide (Lane 4) or against the irrelevant peptide (Lane 2). F, Immunoblot analysis of total viral extract revealed with a commercial positive control IgG (Line 1) or with IgG from a healthy donor’s serum (Lane 2), or with IgG from two different type I diabetes patients’ sera (Lanes 3 and 4). G, Immunoblot analysis of total viral extract revealed with a commercial positive control IgA (Lane 1) or with IgA from a healthy donor’s serum (Lane 2), or with IgA from two different type I diabetes patients’ sera (Lanes 3 and 4).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3585221&req=5

pone-0057729-g001: T1DM peptide shares sequence homology with genome poliprotein CXB4 and induces crossreactive antibodies.A, Sequence homology between T1DM peptide and the genome poliprotein CXB4, analyzed by the basic local alignment search tool using the National Center for Biotechnology Information (NCBI) network service. Vertical line = identical amino acids; asterisk = conservative substitutions B, Frequency of the binding of patients’ sera to COXSA peptide and to total viral extract evaluated by ELISA test. C, Direct binding of affinity-purified antibodies against T1DM (black rhombus), COXSA (black square) and irrelevant (black triangle) peptides, to COXSA synthetic peptide. Data represent absorbance at 405 nm (vertical axis) and antibody concentration µg/ml (horizontal axis). D, Binding of affinity-purified antibodies against COXSA peptide is inhibited by T1DM (black rhombus), COXSA (black square) peptides but not by an irrelevant (black triangle) peptide. Data represent inhibition percentage (vertical axis) and the inhibitor concentration µg/ml (horizontal axis). E, Immunoblot analysis of total viral extract revealed with a commercial positive control IgG (Lane 1) or with antibodies affinity purified against the T1DM peptide (Lane 3) or against the COXSA peptide (Lane 4) or against the irrelevant peptide (Lane 2). F, Immunoblot analysis of total viral extract revealed with a commercial positive control IgG (Line 1) or with IgG from a healthy donor’s serum (Lane 2), or with IgG from two different type I diabetes patients’ sera (Lanes 3 and 4). G, Immunoblot analysis of total viral extract revealed with a commercial positive control IgA (Lane 1) or with IgA from a healthy donor’s serum (Lane 2), or with IgA from two different type I diabetes patients’ sera (Lanes 3 and 4).
Mentions: We enrolled fifty-eight patients (35 males, 23 females) aged 0.8–18.7 years (mean age 8.3 years) with recently diagnosed (1–29 days) type 1 diabetes attending the Department of Pediatrics, Giannina Gaslini Institute, Genova. Diagnosis was based on the American Diabetes Association criteria [24]. Patients were tested for anti-glutamic acid decarboxylase (GADA), anti-insulin (IAA) and anti-tyrosine phosphatase-like protein (IA2A) antibodies (Table S1) within 30 days from the diagnosis and before starting insulin therapy. Commercially available kits were used to detect autoantibodies (Radioimmuno-assay CIS Bio International-Schering SA). One hundred age and sex-matched healthy individuals served as controls. Eight subjects with evidence of Coxsackievirus infection and presence of serum antibodies directed against the Coxsackievirus B4 extract were tested for the presence of antibodies against the T1DM and COXSA peptides (Fig. 1B).

Bottom Line: Coxsackievirus B infection has been linked to the onset of type 1 diabetes; however its precise role has not been elucidated yet.We identified an immunodominant peptide recognized by the majority of individual patients'sera, that shares homology with Coxsackievirus B4 VP1 protein and with beta-cell specific autoantigens such as phogrin, phosphofructokinase and voltage-gated L-type calcium channels known to regulate beta cell apoptosis.Our results provide evidence that in autoimmune diabetes a subset of anti-Coxsackievirus antibodies are able to induce apoptosis of pancreatic beta cells which is considered the most critical and final step in the development of autoimmune diabetes without which clinical manifestations do not occur.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Section of Internal Medicine, University of Verona, Verona, Italy.

ABSTRACT
Type 1 diabetes is characterized by autoimmune destruction of pancreatic beta cells. The role played by autoantibodies directed against beta cells antigens in the pathogenesis of the disease is still unclear. Coxsackievirus B infection has been linked to the onset of type 1 diabetes; however its precise role has not been elucidated yet. To clarify these issues, we screened a random peptide library with sera obtained from 58 patients with recent onset type 1 diabetes, before insulin therapy. We identified an immunodominant peptide recognized by the majority of individual patients'sera, that shares homology with Coxsackievirus B4 VP1 protein and with beta-cell specific autoantigens such as phogrin, phosphofructokinase and voltage-gated L-type calcium channels known to regulate beta cell apoptosis. Antibodies against the peptide affinity-purified from patients' sera, recognized the viral protein and autoantigens; moreover, such antibodies induced apoptosis of the beta cells upon binding the L-type calcium channels expressed on the beta cell surface, suggesting a calcium dependent mechanism. Our results provide evidence that in autoimmune diabetes a subset of anti-Coxsackievirus antibodies are able to induce apoptosis of pancreatic beta cells which is considered the most critical and final step in the development of autoimmune diabetes without which clinical manifestations do not occur.

Show MeSH
Related in: MedlinePlus