Diabetic sera react with the glutamic acid decarboxylase molecule in a dimeric-oligomeric form

M. J. Rowley, Q. Y. Chen, K. L. Teoh, Paul Zimmet, T. Tuomi, W. J. Knowles, I. R. Mackay

Research output: Contribution to journalArticle

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Abstract

Glutamic acid decarboxylase (GAD) is a major autoantigen in insulin-dependent diabetes mellitus (IDDM). This was initially identified as a 64-65 kD molecule according to migration in gels after immunoprecipitation from pancreatic islets. We studied the antigenicity of two different radiolabelled preparations of GAD, derived either by affinity purification from porcine brain and known to contain GAD 65 and GAD 67, or by expression from a cDNA for human GAD 65 by rabbit reticulocyte lysate (RRL). Radiolabelled immunoprecipitated pellets from the reaction of potent antisera to GAD from patients with IDDM were examined by autoradiography after SDS-PAGE under reducing or non-reducing conditions. Also, preparations of porcine brain GAD were 'depleted' of GAD by exposure to antisera, and then similarly re-examined. Autoradiography of radiolabelled GAD either affinity purified from porcine brain, or expressed by RRL, showed that the immunoprecipitated protein migrated under non-reducing conditions according to a M(r) of ~ 110-130 kD, corresponding to dimeric forms of monomeric GAD of ~ 55-65 kD. Depletion by immunoprecipitation of this minor higher M(r) component from preparations of GAD left, in the supernatant, an abundance of GAD of M(r) 64-65 kD corresponding to monomer that was completely non-reactive with potent IDDM sera. We conclude that IDDM sera react with the GAD molecule in a dimeric (or oligomeric) form. Our findings have general connotations for self-tolerance and autoimmunity.

LanguageEnglish
Pages323-328
Number of pages6
JournalClinical and Experimental Immunology
Volume106
Issue number2
DOIs
Publication statusPublished - 1 Jan 1996

Keywords

  • IDDM
  • antigenicity
  • autoantibody
  • dimer
  • glutamic acid decarboxylase
  • oligomer

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

Cite this

Rowley, M. J., Chen, Q. Y., Teoh, K. L., Zimmet, P., Tuomi, T., Knowles, W. J., & Mackay, I. R. (1996). Diabetic sera react with the glutamic acid decarboxylase molecule in a dimeric-oligomeric form. Clinical and Experimental Immunology, 106(2), 323-328. https://doi.org/10.1046/j.1365-2249.1996.d01-827.x
Rowley, M. J. ; Chen, Q. Y. ; Teoh, K. L. ; Zimmet, Paul ; Tuomi, T. ; Knowles, W. J. ; Mackay, I. R. / Diabetic sera react with the glutamic acid decarboxylase molecule in a dimeric-oligomeric form. In: Clinical and Experimental Immunology. 1996 ; Vol. 106, No. 2. pp. 323-328.
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Rowley, MJ, Chen, QY, Teoh, KL, Zimmet, P, Tuomi, T, Knowles, WJ & Mackay, IR 1996, 'Diabetic sera react with the glutamic acid decarboxylase molecule in a dimeric-oligomeric form', Clinical and Experimental Immunology, vol. 106, no. 2, pp. 323-328. https://doi.org/10.1046/j.1365-2249.1996.d01-827.x

Diabetic sera react with the glutamic acid decarboxylase molecule in a dimeric-oligomeric form. / Rowley, M. J.; Chen, Q. Y.; Teoh, K. L.; Zimmet, Paul; Tuomi, T.; Knowles, W. J.; Mackay, I. R.

In: Clinical and Experimental Immunology, Vol. 106, No. 2, 01.01.1996, p. 323-328.

Research output: Contribution to journalArticle

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AU - Rowley, M. J.

AU - Chen, Q. Y.

AU - Teoh, K. L.

AU - Zimmet, Paul

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AU - Knowles, W. J.

AU - Mackay, I. R.

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