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Monoclonal antibody Alz‐50 reacts with bovine and human serum albumin
Author(s) -
Davis P. K.,
Johnson G. V. W.
Publication year - 1994
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490390510
Subject(s) - bovine serum albumin , epitope , monoclonal antibody , antibody , microbiology and biotechnology , serum albumin , biochemistry , chemistry , gene isoform , human brain , biology , immunology , gene , neuroscience
Abstract Alz‐50, a monoclonal antibody originally prepared using Alzheimer brain homogenates, reacts with PHF‐tau and normal tau on immunoblots, and stains specific neuronal populations in sections from Alzheimer's disease brain. Although the Alz‐50 epitope has been mapped to amino acids 2–10 present in all human tau isoforms, minimal Alz‐50 immunoreactivity is present in tissue from control brain, suggesting Alz‐50 binding may be dependent on tau conformational differences. The absence of conclusive results concerning Alz‐50 binding presents the possibility of Alz‐50 immunoreactivity with proteins other than tau. The present study demonstrates Alz‐50 crossreactivity with denatured bovine serum albumin (BSA) and human serum albumin (HSA). Using LA‐N‐5 neuroblastoma cells, BSA from serum‐containing media was present in cell homogenates and was found to be Alz‐50‐reactive on immunoblots. In fact, Alz‐50 (0.1 μg/ml) recognized as little as 78 ng of BSA and 312 ng of HSA. Since Alz‐50 does not recognize native BSA, blocking of immunoblots with 3% BSA did not alter Alz‐50 reactivity with tau from LA‐N‐5 cells. On SDS‐polyacrylamide gels, HSA (∼ 69 kDa) migrates very closely to the pattern of A68 (PHF‐tau) from Alzheimer brain homogenates. Hence, the presence of BSA or other albumins in cell or brain homogenates may be an important concern when using the Alz‐50 antibody. © 1994 Wiley‐Liss, Inc.