title: Preparation and testing of diabetes autoantibody controls.
abstract: Stocks of the WHO islet cell antibody, GAD(65) antibody, and IA-2 antibody standard (NIBSC 97/550) are now very limited. We have therefore made and tested a series of control preparations in which human monoclonal autoantibodies to IA-2 and to GAD(65) were diluted in antibody-negative human serum to different concentrations. Three different diabetes autoantibody controls (DAC 1-3) were made as was a negative control preparation. Aliquots containing 1 mL of autoantibodies in serum were freeze-dried. After reconstitution (with 1 mL of water) the controls were tested by (125)I-IA-2 immunoprecipitation assay (IPA), (125)I-GAD(65) IPA, GAD(65) Ab ELISA and IA-2 Ab ELISA (kits from RSR Ltd.) and for ICA by immunofluorescence test (IFT). DAC1 is particularly suitable as a control for the (125)I IA-2 IPA; DAC2 is suitable for the (125)I-GAD(65) IPA, GAD(65) Ab ELISA, and IA-2 Ab ELISA; and DAC3 is suitable for the ICA IFT. Freeze-dried preparations showed good stability at 37 degrees C. Reconstituted liquid preparations were stable when stored at 4 degrees C and at 37 degrees C. Availability of an essentially unlimited supply of these reagents should be useful in establishing reproducible and comparable measurements of diabetes autoantibodies in different laboratories using different assays.
authors.affiliation: FIRS Laboratories, RSR Ltd, Llanishen, Cardiff, Wales, UK.
authors.forename: H
authors.initials: H
authors.lastname: Brooking
authors.forename: M J
authors.initials: MJ
authors.lastname: Powell
authors.forename: M
authors.initials: M
authors.lastname: Amoroso
authors.forename: C
authors.initials: C
authors.lastname: Betterle
authors.forename: B
authors.initials: B
authors.lastname: Pedini
authors.forename: G
authors.initials: G
authors.lastname: Coco
authors.forename: J
authors.initials: J
authors.lastname: Furmaniak
authors.forename: B Rees
authors.initials: BR
authors.lastname: Smith
mesh_terms: D000911:Antibodies, Monoclonal / Q000032:analysis; D001323:Autoantibodies / Q000032:analysis* / Q000097:blood / Q000302:isolation & purification*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000592:standards; D005968:Glutamate Decarboxylase / Q000276:immunology; D006801:Humans; D007158:Immunologic Techniques / Q000592:standards*; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8 / Q000276:immunology; D012015:Reference Standards
chemical_list: D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2