Characterisation of an epitope specific to the neuron-specific isoform of human enolase recognised by a monoclonal antibody raised against a synthetic peptide corresponding to the C-terminus of beta/A4-protein.
Antibodies to synthetic peptides corresponding to different regions of beta/A4-protein recognize deposits of amyloid in the brains of patients with Alzheimer's disease. Down's syndrome cases and in the normal ageing brain. We have prepared a monoclonal antibody, mAb 22.212, raised against a synthetic C-terminal peptide of beta/A4 protein (residues 28-40) which labelled senile plaques in Alzheimer's disease after proteolytic treatment of tissue sections. In addition to recognising synthetic beta/A4-peptides that include the C-terminal residues 28-42, the mAb 22.212 was found to cross-react with a soluble, 47 kDa protein found in brain homogenates. This protein was shown, by amino acid sequence analysis and immunoassay, to be neuron-specific enolase (NSE). The mAb 22.212 did not recognize the non-neuronal enolase (NNE) or muscle-specific enolase (MSE) isoforms and its epitope was mapped to a short stretch of amino-acids unique to NSE, near the C-terminus. The cross-reactive NSE epitope is sited between residues 402-423 in NSE and shows no common sequence with beta/A4, perhaps suggesting that it is a conformational epitope. The significance and applications of these findings are discussed.
Harrington
C R
CR
Cambridge Brain Bank Laboratory, University of Cambridge Department of Psychiatry, UK.
Quinn
G B
GB
Hurt
J
J
Day
I N
IN
Wischik
C M
CM
D000544:Alzheimer Disease / Q000473:pathology; D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000737:chemistry / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D003429:Cross Reactions; D000939:Epitopes / Q000032:analysis* / Q000276:immunology; D006624:Hippocampus / Q000737:chemistry / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology; D010751:Phosphopyruvate Hydratase / Q000032:analysis* / Q000276:immunology
D016229:Amyloid beta-Peptides; D000911:Antibodies, Monoclonal; D000939:Epitopes; D010446:Peptide Fragments; D010751:Phosphopyruvate Hydratase