T. Motoike et K. Unsicker, Identification of a potent neurotrophic substance for ciliary ganglionic neurons in fetal calf serum as insulin-like growth factor II, J NEUROSC R, 56(4), 1999, pp. 386-396
When fetal calf serum (FCS) alone is used as a trophic support for cultured
chicken parasympathetic ciliary ganglionic (cCG) neurons, it does not show
any survival-promoting effects on these neurons, When FCS is applied to he
parin-affinity chromatography, however, potent survival-promoting activity
is obtained in the fraction eluted,vith 0.5 M NaCl, Using cCG neurons as a
bioassay system, this neurotrophic activity was purified by a combination o
f heparin-affinity chromatography, gel filtration chromatography, and Sep-P
ak C18 cartridge. The 40-50-kDa fractions from the gel filtration column,vi
th strong survival-promoting activity were shown to contain insulin-like gr
owth factor II (IGF-II) by immunoblot analysis. By acidification, the survi
val-promoting activity and IGF-II were translocated together from the 40-50
-kDa to the 7-10-kDa fractions, and the survival-promoting activity in the
7-10-kDa fractions was blocked by an anti-IGF-II neutralizing monoclonal an
tibody. These results indicate that the neurotrophic substance in 0.5 M NaC
l-eluate from heparin-affinity chromatography is IGF-II and that mechanisms
may exist in vivo for the activation of latent IGF-II, whose biological ef
fects may be blocked by its specific binding proteins. J, Neurosci, Res. 56
:386-396, 1999, (C) 1999 Wiley-Liss, Inc.