Autoantibodies to recombinant canine proinsulin in canine diabetic patients.
OBJECTIVE
To determine whether dogs with spontaneously-occurring diabetes mellitus demonstrate serological reactivity to proinsulin.


METHODS
Serum samples were collected from 15 newly-diagnosed diabetic, 15 insulin-treated diabetic and 15 non-diabetic control dogs.


METHODS
Canine proinsulin was cloned into a prokaryotic expression vector to generate recombinant poly-histidine-tagged protein in Escherichia coli. A Western blotting assay was developed for detection of proinsulin autoantibodies in canine sera.


RESULTS
Reactivity to canine proinsulin was detected in 3 of 15 control dogs, 8 of 15 newly-diagnosed diabetic dogs and 6 of 15 insulin-treated diabetic patients. Of these reactors, only 1 control dog, 1 newly-diagnosed diabetic dog and 3 insulin-treated diabetic dogs recognised porcine insulin by ELISA, suggesting that the remaining proinsulin reactors might have been recognising proinsulin-specific epitopes.


CONCLUSIONS
This study suggests that proinsulin autoantibodies are present in a proportion of diabetic dogs. Further work is required to refine the assay and clarify the significance of these autoantibodies.
Davison
Lucy J
LJ
Dept. of Pathology and Infectious Diseases, Royal Veterinary College, London, UK; Dept. Veterinary Medicine, Queen's Veterinary School Hospital, University of Cambridge, UK. Electronic address: lucy.davison@cimr.cam.ac.uk.
Herrtage
Michael E
ME
Dept. Veterinary Medicine, Queen's Veterinary School Hospital, University of Cambridge, UK.
Catchpole
Brian
B
Dept. of Pathology and Infectious Diseases, Royal Veterinary College, London, UK.
D000818:Animals; D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000096:biosynthesis / Q000276:immunology*; D015153:Blotting, Western / Q000662:veterinary; D003001:Cloning, Molecular; D003920:Diabetes Mellitus / Q000097:blood / Q000276:immunology / Q000662:veterinary*; D004283:Dog Diseases / Q000097:blood / Q000276:immunology*; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D007328:Insulin / Q000276:immunology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011384:Proinsulin / Q000096:biosynthesis / Q000276:immunology*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology*
D001323:Autoantibodies; D001324:Autoantigens; D007328:Insulin; D011994:Recombinant Proteins; D011384:Proinsulin