Linked Life Data

2148521

Source:http://linkedlifedata.com/resource/pubmed/id/2148521

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
1991-2-20
pubmed:abstractText
In this work we studied the role of the classical pathway complement component C4b in the activation of the alternative pathway. It was found that nascent C3b attaches with high efficiency to C4b and that C3b in C4bC3b complexes is protected from inactivation by factors H and I. Activation of C3 by factors B and D in the presence of Mg2+ ions and excess C4b led to 35% incorporation of nascent C3b into C4bC3b complexes in the fluid phase. In comparison, when human IgG was tested as an acceptor under similar conditions, only 12% of generated C3b was incorporated into IgGC3b complexes. The half-life time of dissociation of C3b from purified C4bC3b complexes was approximately 2.3 h at 37 degrees C. C4b in these complexes protected C3b from inactivation as effectively as any known alternative pathway activator. Thus, C3b bound to C4b was tenfold more stable than free C3b or C3b bound to a nonactivating surface. In comparison, the protection provided by attachment to human IgG was only 67% of that of C4b. The results provide an explanation for observations of alternative pathway recruitment following classical pathway activation and for the stability of the classical pathway C5 convertase on surfaces which do not provide protection for C3b from factors H and I.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0014-2980
pubmed:author
pubmed:issnType
Print
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2555-61
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
A mechanism of activation of the alternative complement pathway by the classical pathway: protection of C3b from inactivation by covalent attachment to C4b.
pubmed:affiliation
Department of Biochemistry, University of Texas Health Center, Tyler 75710.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't