Linked Life Data

557068

Source:http://linkedlifedata.com/resource/pubmed/id/557068

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1977-4-15
pubmed:abstractText
Aggregated IgG coupled covalently with bis-diazobenzidine (BDB-IgG) and labeled with 3H-diazobenzene (3H-BDB-IgG) has been used to study the binding of soluble IgG aggregates to human platelets in relationship to the release of the contents of intracellular granules (e.g., serotonin). In washed cell suspensions a minimum of 0.14 to 0.2 mug 3H-BDB-IgG per 5 X 10(8) platelets (40 to 70 aggregates per cell) was required for the triggering of the release reaction and cell aggregation. Binding was independent of divalent cations. The Arrhenius plot gave a straight line between 0 to 37 degrees C and a Q10 of 1.6. Neither inhibitors of the release reaction nor energy metabolism, nor formaldehyde fixation of the platelets affected binding. Bound 3H-BDB-IgG was not significantly eluted by IgG, bovine albumin (BSA), buffer, or plasma. Binding to washed platelets was more strongly inhibited by human IgG than by F(ab')2, bovine IgG, human albumin (HSA), or BSA. Plasma was an even more effective inhibitor of both binding and release. Plasma deficient in IgG or depleted of complement retained its inhibitory capacity. In the presence of plasma, at physiologic ratios of plasma and platelets, no release of serotonin was observed. Binding, although inhibited in rate, nevertheless occurred. It was enhanced by divalent cation chelation and had a Q10 of 2.5. The release reaction of washed platelets to which 3H-BDB-IgG had been bound in the presence of HSA or BSA was also inhibited by the subsequent addition of plasma or plasma proteins (human IgG being more effective than bovine IgG, F(ab')2, HSA, or BSA). 3H-BDB-IgG bound in the presence of either plasma or human IgG did not induce release when the platelets were subsequently suspended in media lacking these proteins. Thus, it appears that the platelet Fc receptor binds 3H-BDB-IgG by a process which is effectively inhibited by plasma, or by free IgG with an intact Fc, and to some extent by high concentrations of other proteins. The effects of bound IgG aggregates are dependent on the other proteins present both during binding and subsequently added. The mechanism of such receptor modulation and its implications in vivo are discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:volume
118
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
514-24
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1977
pubmed:articleTitle
Studies of the mechanism of the human platelet release reaction induced by immunologic stimuli. III. Relationship between the binding of soluble IgG aggregates to the Fc receptor and cell response in the presence and absence of plasma.
pubmed:publicationType
Journal Article