Monoclonal Antibodies against Heparin-Binding Growth Facto 1: Neutralization of Biological Activity and Recognition of Specific Amino Acid Sequence

Abstract

A panel of three monoclonal antibodies against heparin-binding growth factor-1 (HBGF-1) was obtained. These antibodies, Ab-47α, Ab-15, Ab-29, were able to recognize HBGF-1 but not HBGF-2. One of the antibodies, Ab-47α, was identified as a HBGF-1 neutralizing antibody on the basis of its ability to inhibit the binding of [125I]HBGF-1 to receptors on HepG-2 cells and the proliferation of fetal bovine heart endothelial cells induced by HBGF-1. Ab-15 reacted with truncated HBGF-1(Mr= 16,000), intact HBGF-1( Mr= 18,000) and mutant HBGF-1U which lacks a putative nuclear translocation sequence (amino acid residues 21 to 27 of HBGF-1). Ab-29 reacted with only truncated HBGF-1 and was thought to recognize the putative nuclear translocation sequence of HBGF-1. The three monoclonal antibodies did not inhibit the binding of [125I]HBGF-1 to heparin. These data indicate that each monoclonal antibody recognizes a distinct epitope of HBGF-1 and identifies them as useful reagents for evaluating functional domains and biological roles of HBGF-1.