Truncated chicken interleukin-1beta with increased biologic activity.
Chicken interleukin-1beta (ChIL-1beta) is synthesized as a precursor molecule that unlike its mammalian counterpart, lacks a typical caspase-1 cleavage site. Therefore, it was unclear if proteolytic cleavage of ChIL-1beta can occur and if cleavage might modulate the biologic activity of this cytokine. Using an avian indicator cell line that carries an NF-kappaB-regulated luciferase reporter gene, we established a sensitive and highly specific bioassay for ChIL-1beta. Experiments with a rabbit antiserum indicated that the NF-kappaB-stimulating activity in supernatants of lipopolysaccharide (LPS)-treated chicken HD-11 macrophages is largely due to IL-1beta and that proteolytic processing of natural and recombinant ChIL-1beta is not very efficient. Functional analyses further revealed that cDNAs for either full-length or N-terminally truncated chicken ChIL-1beta yielded active cytokine. A truncated molecule that closely resembled putative mature ChIL-1beta exhibited more than 100-fold enhanced biologic activity after expression in mammalian cells, indicating that precursor cleavage is indeed of critical importance for maximal activity.
Gyorfy
Zsuzsa
Z
Department of Virology, University of Freiburg, Germany.
Ohnemus
Annette
A
Kaspers
Bernd
B
Duda
Erno
E
Staeheli
Peter
P
D000818:Animals; D001665:Binding Sites; D001681:Biological Assay; D002460:Cell Line; D002645:Chickens / Q000235:genetics / Q000276:immunology*; D018076:DNA, Complementary / Q000235:genetics; D017930:Genes, Reporter; D006801:Humans; D007375:Interleukin-1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008156:Luciferases / Q000235:genetics; D016328:NF-kappa B / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D011784:Quail; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D018076:DNA, Complementary; D007375:Interleukin-1; D016328:NF-kappa B; D011994:Recombinant Proteins; D008156:Luciferases