Location of an epitope shared by Alzheimer's amyloid peptide and brain creatine kinase using a newly developed monoclonal antibody.
Amyloid plaques, composed mainly by a peptide termed A4-amyloid, derived by proteolytic processing from the amyloid precursor protein (APP), are a hallmark in the brain of Alzheimer's disease patients. We have prepared a collection of monoclonal antibodies as tools to study APP expression and proteolysis in different systems. One of these, 5AH10, raised against residues 9-22 of A4-peptide, was selected for its ability to recognize only A4 subpeptides having the intact APP-secretase target sequence, as well as whole recombinant APP. By using synthetic subpeptides, we have located 5AH10 epitope between amino acids 15 and 22 of A4. In addition, 5AH10 showed a strong immunoreactivity to a 47 kDa protein present in rat brain extracts, that was identified as the B (brain specific) subunit of creatine kinase by immunochemical data and direct N-terminal sequencing. The cross-reaction observed is most probably due to a high degree of sequence identity between amino acids 15 to 22 of A4 peptide and amino acids 9 to 16 of rat B creatine kinase. 5AH10 did not recognize the muscle specific isoform (M subunit) of rat creatine kinase, nor the B subunit of human and rabbit creatine kinase, suggesting that glutamine at first position of the epitope is essential for antigen recognition by 5AH10.
Cazorla
P
P
Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Spain.
Aldudo
J
J
Haas
C
C
Vázquez
J
J
Valdivieso
F
F
Bullido
M J
MJ
D000544:Alzheimer Disease / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000235:genetics / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal; D001921:Brain / Q000201:enzymology / Q000276:immunology; D003402:Creatine Kinase / Q000235:genetics / Q000276:immunology*; D003429:Cross Reactions; D000939:Epitopes / Q000235:genetics; D006801:Humans; D007120:Immunochemistry; D051379:Mice; D008969:Molecular Sequence Data; D011817:Rabbits; D051381:Rats; D017386:Sequence Homology, Amino Acid
D016229:Amyloid beta-Peptides; D000911:Antibodies, Monoclonal; D000939:Epitopes; D003402:Creatine Kinase