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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1989-7-31
pubmed:abstractText
Two murine, keyhole limpet hemocyanin-specific, Th cell clones were studied for their ability to respond to antibody-mediated stimulation of the TCR complex or to Ag-pulsed accessory cells by hydrolyzing inositol phospholipids. Both clones were positive for the determinant expressed on the epsilon chain of CD3 that is recognized by the mAb, 145-2C11 (2C11 mAb); one clone also expressed the V beta 8 epitope of the alpha/beta chains of the TCR recognized by the F23.1 mAb. Treatment of these cells with 2C11 or F23.1 mAb adsorbed onto polystyrene beads induced a time-dependent accumulation of inositol phosphates (IP). Keyhole limpet hemocyanin-pulsed accessory cells which expressed the appropriate MHC phenotype also induced IP accumulation, whereas no response was induced by medium-treated or MHC congenic accessory cells. The hydrolysis of inositol phospholipids induced by TCR perturbation depended upon the presence of exogenous Ca2+; Mg2+ did not substitute for Ca2+. Treatment of cells with ionomycin at concentrations up to 30 microM was unable to induce hydrolysis of inositol phospholipids, indicating that entrance of Ca2+ was itself insufficient to generate IP. Stimulated IP generation was rapidly blocked upon addition of EGTA to the incubation medium. Reducing the level of exogenous Ca2+ decreased the production of inositol mono-, bis-, and trisphosphate isomers similarly, suggesting that extracellular Ca2+ was required for the initiation of the hydrolysis rather than affecting phospholipase C affinity for its substrates. We concluded that activation of inositol phospholipid hydrolysis by perturbation of the TCR complex in the Th cell clones under investigation displays a Ca2+-dependent component which is likely to be proximal to IP generation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
143
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
587-95
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Hydrolysis of inositol phospholipids induced by stimulation of the T cell antigen receptor complex in antigen-specific, murine helper T cell clones. Requirement for exogenous calcium.
pubmed:affiliation
Laboratory of Cell Biology, US Food and Drug Administration, Bethesda, MD 20892.
pubmed:publicationType
Journal Article