Abstract
The anti-hIGF-I monoclonal antibody, alpha-sm1.2, was found to have substantial crossreactivity with human and rat IGF-II, but recognized rat IGF-I only when this ligand was present at very high concentration. (E50 for hIGF-I approximately 3.5 ng/tube vs. approximately 12,000 ng/tube for rat IGF-I). In the context of previous studies to define the epitope(s) of alpha-sm1.2, these findings point to the critical importance of aspartic acid at residue 20 in the B domain in determining the species and ligand specificity of this antibody. Previous studies using this antibody in rodent tissues may require reinterpretation in the light of these findings.
MeSH terms
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Amino Acid Sequence
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Animals
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Antibodies, Monoclonal / analysis
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Antibodies, Monoclonal / chemistry
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Antibodies, Monoclonal / immunology*
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Antibody Specificity*
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Binding, Competitive
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Cross Reactions
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Epitopes / immunology
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Humans
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Insulin-Like Growth Factor I / analysis
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Insulin-Like Growth Factor I / chemistry
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Insulin-Like Growth Factor I / immunology*
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Insulin-Like Growth Factor II / analysis
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Insulin-Like Growth Factor II / chemistry
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Insulin-Like Growth Factor II / immunology
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Ligands
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Mice
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Molecular Sequence Data
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Rats
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Sheep
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Species Specificity
Substances
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Antibodies, Monoclonal
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Epitopes
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Ligands
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Insulin-Like Growth Factor I
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Insulin-Like Growth Factor II