Title : Detection of novel carbohydrate binding activity of interleukin-1
Abstract :
Tamm-Horsfall glycoprotein ( THGP ) and the oligosaccharide fraction liberated from THGP by hydrazinolysis inhibited tetanus toxoid-induced T cell proliferation
Intact THGP showed approximately 100-fold more inhibitory activity than the free oligosaccharides
After fractionating the oligosaccharides by anion-exchange column chromatography, the inhibitory activity could be detected in a sialidase-resistant acidic oligosaccharide fraction (fraction AR)
The inhibitory activity of fraction AR was not observed when the fraction was added to the T cell culture medium 24 h after the addition of tetanus toxoid
Increased concentration of interleukin (IL) 1beta and decreased concentration of IL-2 were observed in the T cell culture medium after the addition of fraction AR
The oligosaccharides in fraction AR also inhibited the growth of an IL-1-dependent cell line, D10-G4
These results strongly suggested that the oligosaccharides in fraction AR bind to IL-1beta and suppress its cytokine activity
IL-1beta actually bound to the fraction AR immobilized on an amino-bonded thin layer plate
Fractionation of the oligosaccharides indicated that only oligosaccharides containing an N-acetylgalactosamine residue and a sulfate residue bound specifically to IL-1beta
Removal of either the sulfate residue or the N-acetylgalactosamine residue from the oligosaccharides abolished both the proliferation-inhibition and IL-1beta binding activities
Since IL-1beta did not bind to thyroid-stimulating hormone , which has the sulfate group at C-4 of the N-acetylgalactosamine residue in its N-linked sugar chains, residue in its N-linked sugar chains, the binding of IL-1beta toward oligosaccharides in fraction AR was considered to be highly specific