Linked Life Data

9780158

Source:http://linkedlifedata.com/resource/pubmed/id/9780158

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1998-11-4
pubmed:abstractText
CD28 and CTLA-4 are related receptors that differentially regulate T cell activation. Despite the fact that they bind the same ligands, CD28 is a classical costimulator enhancing proliferation whereas CTLA-4 appears to perform negative regulatory functions. In this study, we have utilized the natural ligand for CD28 and CTLA-4 (CD80) to determine under what circumstances positive and negative effects are operative. We show here that the stimulation of purified human T cells with phorbol ester and ionomycin is inhibited in the presence of Chinese hamster ovary (CHO) cells expressing CD80. This inhibition is reversed by blocking with both anti-CD80 or Fab fragments of anti-CTLA-4 but also requires CD28 engagement. Furthermore, we show that the inhibitory function of CD80 requires elevated intracellular calcium since inhibition was observed only in the presence of ionomycin. In the absence of intracellular calcium elevation, CTLA-4 was not expressed at the cell surface, and CD80 acted positively as a costimulator of T cells, via CD28. These results demonstrate that the natural ligand CD80 can either costimulate or inhibit T cell responses depending on the conditions of T cell stimulation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
161
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3919-24
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Positive and negative regulation of human T cell activation mediated by the CTLA-4/CD28 ligand CD80.
pubmed:affiliation
Department of Pharmacology, University of Bath and Bath Institute for Rheumatic Diseases, United Kingdom.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't