Linked Life Data

2583226

Source:http://linkedlifedata.com/resource/pubmed/id/2583226

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1989-12-22
pubmed:abstractText
As determined by native polyacrylamide gel electrophoresis (PAGE) and gel chromatography the molecular mass of native tumor necrosis factor (TNF)-alpha was approximately 35 kDa. When incubated at low concentrations (less than 1 nM) 125I-labeled TNF-alpha and unlabeled TNF-alpha rapidly multimerized or dissociated into monomers and bioactivity decreased. Sodium dodecyl sulfate (SDS)-PAGE analysis of cross-linked 125I-labeled TNF-alpha demonstrated bands of multi- and trimeric TNF-alpha in addition to dominating bands of dimers and monomers. Tri-, di- and monomeric TNF-alpha were recovered from SDS-PAGE gels and allowed to renature. Of the original receptor-binding activity, 10%-15% was obtained with cross-linked TNF-alpha dimers, whereas none was recovered from preparations of trimeric TNF-alpha. Multimeric and monomeric TNF-alpha exhibited little or no binding activity, and cell-bound, cross-linked TNF-alpha which was dissociated from cellular binding sites was mainly dimeric. 125I-labeled TNF-alpha bound to lymphokine-activated killer (LAK) cells and binding kinetics were much similar (Kd approximately 100 pM) to those reported in other normal cell types. The number of receptors per LAK cell was approximately 4 x 10(3). Cross-linking of TNF-alpha to binding sites in U-937 and LAK cells yielded a receptor-ligand complex of about 80/90 kDa. At 37 degrees C, 125I-labeled TNF-alpha was rapidly internalized and degraded in L-929, U-937 and LAK cells. Degradation of ligand and recycling of receptors were blocked in the presence of methylamine. Methylamine significantly inhibited TNF-alpha-mediated cytolysis of L-929 cells and caused a quantitatively corresponding reduction in cellular TNF-alpha uptake, indicating that L-929 lysis was mediated by receptors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0014-2980
pubmed:author
pubmed:issnType
Print
pubmed:volume
19
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1887-94
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Bioactive human recombinant tumor necrosis factor-alpha: an unstable dimer?
pubmed:affiliation
Department of Clinical Immunology, Skejby Sygehus, Aarhus N, Denmark.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't