Localization of the epitope of a monoclonal antibody against human insulin-like growth factor binding protein-1, functionally interfering with insulin-like growth factor binding.
In order to identify regions in insulin-like growth factor binding protein-1 involved in the binding of IGFs, we tested three monoclonal antibodies, designated MAb A, B, and C on their interference with IGF-binding. Monoclonal A interfered with the binding of IGF to IGFBP-1 as determined by immunoprecipitation whereas monoclonal B and C did not. Furthermore MAb A was found to abolish IGFBP-1 inhibition of IGF stimulation in an in vitro proliferation assay. The epitopes of all three monoclonal antibodies were found to be located within the C-terminal part of IGFBP-1. The regions surrounding residue 188-196 and 222-227 are especially important for antibody recognition. These results indicate that MAb A functionally interferes with the binding of IGF to IGFBP-1. Furthermore, we suggest that part of the epitope of MAb A is located at or sterically near the IGF binding domain of IGFBP-1.
Schuller
A G
AG
Department of Pediatrics, Erasmus University/Sophia Childrens Hospital, Rotterdam, The Netherlands.
Lindenbergh-Kortleve
D J
DJ
de Boer
W I
WI
Zwarthoff
E C
EC
Drop
S L
SL
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D000939:Epitopes / Q000032:analysis* / Q000276:immunology; D006801:Humans; D006825:Hybridomas; D018970:Insulin-Like Growth Factor Binding Protein 1; D051379:Mice; D008969:Molecular Sequence Data; D017354:Point Mutation; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013002:Somatomedins / Q000037:antagonists & inhibitors* / Q000378:metabolism
D000911:Antibodies, Monoclonal; D002352:Carrier Proteins; D000939:Epitopes; D018970:Insulin-Like Growth Factor Binding Protein 1; D011993:Recombinant Fusion Proteins; D013002:Somatomedins