NEUTRALIZING IGF-1 MONOCLONAL-ANTIBODY WITH CROSS-SPECIES REACTIVITY

We report the generation of a murine IGF-1 monoclonal antibody designa ted 35117, which exhibits unique cross-species reactivity. The antibod y recognizes recombinant human and rat IGF-1 in ELISA, Western blots, and in an I-125-recombinant human IGF-1 Scintillation Proximity Assay. In addition, 35117 blocks cell proliferation induced by recombinant h uman and rat IGF-1, and inhibits cell proliferation induced by sera fr om human, rat, calf, dog, goat, or mouse. The antibody inhibits rat IG F-1 binding to IGF-1 receptors, and prevents IGF-1-stimulated receptor and IRS-1 phosphorylation in LISN C4 cells, an IGF-1 receptor-transfe cted cell line. The cross-species and neutralizing properties of 35117 may be useful in in vitro and in vivo animal studies for elucidating the role of IGF-1 in cancer, rheumatoid arthritis, and other diseases.