CONSTRUCTION OF A SENSITIVE ENZYME-IMMUNOASSAY FOR HUMAN FIBROBLAST GROWTH-FACTOR-9

Hybridomas secreting monoclonal antibodies (MAbs) against human fibrob last growth factor 9 (FGF-9) were established using recombinant human (rh) FGF-9 N33 as the immunogen, Among these, MAb 150-59 demonstrated a potent neutralizing activity against FGF-9, It arrested the FGF-9-in duced growth of BALB/c 3T3 A31 cells at an equimolar dose of the facto r, It also abrogated the in vivo thrombopoietic activity of FGF-9. Mit ogenic activity of several other FGF family members such as FGF-1, FGF -2, and FGF-4 was not neutralized by this MAb, A sensitive sandwich en zyme immunoassay for FGF-9 was developed employing MAbs 150-59 and 13- 3, The detection limit of this system was 3 pg/well, In this assay sys tem, FGF-1 and FGF-2 were not cross-reactive up to 1 mu g/well. Using this system, the distribution of FGF-9 in rat organs was examined. FGF -9 could be detected only in the extract of rat cerebellum, Also, we d etected a high amount of FGF-9 in the culture supernatant of certain c ell lines originated from human tumor, These findings suggest that thi s enzyme immunoassay system may be used to clarify biological meaning of FGF-9.