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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
1990-9-27
pubmed:abstractText
Culture medium conditioned by phorbol 12-myristate 13-acetate-differentiated THP-1 cells contained interleukin 1 (IL-1) antagonist activity as measured by inhibition of both IL-1 beta binding to receptors on YT cells and inhibition of IL-1/phytohemagglutinin-stimulated IL-2 synthesis by LBRM-33-1A5 T cells. Based on their ability to compete for 125I-IL-1 beta binding to receptors on YT cells, four distinct antagonist proteins were purified from THP-1 cell conditioned medium using a combination of ion-exchange, hydrophobic interaction, and size exclusion chromatographies. The four proteins had different isoelectric points with molecular masses in the range 22-26 kDa and had similar specific activities for inhibition of IL-1 beta binding to cell surface receptors (Ki values 0.33-0.64 nM) and for inhibition of IL-1/phytohemagglutinin-stimulated IL-2 synthesis by 1A5 cells (IC50 values 25-100 pM). Amino-terminal sequence analysis of the two major forms (25 kDa/pI 5.1 and 22 kDa/pI 5.8) revealed complete identity for the first 27 residues in both forms. Based on the results of peptide mapping, amino acid compositional analysis and immune blotting, all of the forms were deduced to be variants of a common protein. Deglycosylation of the antagonist proteins with N-glycanase converted them to a common form (22 kDa/pI 5.8), indicating that the four isoforms represent glycosylation variants of a common protein and that asparagine-linked oligosaccharides are responsible for the observed size and charge heterogeneity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
265
pubmed:owner
NLM
pubmed:authorsComplete
N
pubmed:pagination
14505-11
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Purification and characterization of interleukin 1 receptor level antagonist proteins from THP-1 cells.
pubmed:affiliation
Department of Cell Biology, Upjohn Company, Kalamazoo, Michigan 49007.
pubmed:publicationType
Journal Article