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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
1996-8-26
pubmed:abstractText
Treatment of T lymphocytes with phorbol ester and anti-CD28 monoclonal antibody (mAb) can induce proliferation and interleukin 2 production by triggering still undefined intracellular signaling pathways. We have developed a deglycosylation procedure that allows the precise identification of a distinct CD28 protein band, facilitating the analysis of activation-dependent changes in the phosphorylation state of CD28. Phorbol 12-myristate 13-acetate (PMA) treatment induced the in vitro phosphorylation of CD28 on threonine as detected in immune complex kinase assays. This effect of PMA was (i) rapid, preceding a PMA-induced increase in CD28 surface expression; (ii) occurred using kinase buffer containing either manganese or magnesium; and (iii) was found in human peripheral T cells, Jurkat T cells, and in a Jurkat subclone, J.Cam1, that is deficient in Lck tyrosine kinase activity. In contrast, anti-CD28 monoclonal antibody stimulation led to in vitro phosphorylation of CD28 on tyrosine that was manganese-dependent and required Lck tyrosine kinase activity, as it was undetectable in J.Cam1 cells. Importantly, CD28 was phosphorylated on tyrosine in vivo as detected with anti-phosphotyrosine antibodies after stimulation with anti-CD28 monoclonal antibody. The in vivo tyrosine phosphorylation of CD28 was inhibited by PMA treatment and was absent in J.Cam1 cells. Thus, the CD28 coreceptor can trigger different intracellular signaling pathways, depending upon the nature of the initial costimulatory signal.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
271
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13362-70
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Differential phosphorylation of the T lymphocyte costimulatory receptor CD28. Activation-dependent changes and regulation by protein kinase C.
pubmed:affiliation
Division of Pediatric Oncology, Dana-Farber Cancer Institute, Hematology-Oncology Division, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't