Molecular basis for species and ligand specificity of a monoclonal antibody raised against human IGF-I.
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.
Van Wyk
J J
JJ
Department of Pediatrics, University of North Carolina School of Medicine, Chapel Hill 27599, USA.
Bruton
E T
ET
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis / Q000737:chemistry / Q000276:immunology*; D000918:Antibody Specificity; D001667:Binding, Competitive; D003429:Cross Reactions; D000939:Epitopes / Q000276:immunology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000737:chemistry / Q000276:immunology*; D007335:Insulin-Like Growth Factor II / Q000032:analysis / Q000737:chemistry / Q000276:immunology; D008024:Ligands; D051379:Mice; D008969:Molecular Sequence Data; D051381:Rats; D012756:Sheep; D013045:Species Specificity
D000911:Antibodies, Monoclonal; D000939:Epitopes; D008024:Ligands; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II