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.