CTL activation is induced by cross-linking of TCR/MHC-peptide-CD8/p56lck adducts in rafts.

Details

Serval ID
serval:BIB_2AFEBA590A51
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
CTL activation is induced by cross-linking of TCR/MHC-peptide-CD8/p56lck adducts in rafts.
Journal
European Journal of Immunology
Author(s)
Doucey M.A., Legler D.F., Boucheron N., Cerottini J.C., Bron C., Luescher I.F.
ISSN
0014-2980[print], 0014-2980[linking]
Publication state
Published
Issued date
2001
Volume
31
Number
5
Pages
1561-1570
Language
english
Abstract
To investigate the role of the coreceptor CD8 and lipid rafts in cytotoxic T lymphocyte (CTL) activation, we used soluble mono-and multimeric H-2Kd-peptide complexes and cloned S14 CTL specific for a photoreactive derivative of the Plasmodium berghei circumsporozoite (PbCS) peptide 252-260 [PbCS(ABA)]. We report that activation of CTL in suspension requires multimeric Kd-PbCS(ABA) complexes co-engaging TCR and CD8. Using TCR ligand photo-cross-linking, we find that monomeric Kd-PbCS(ABA) complexes promote association of TCR/CD3 with CD8/p56lck. Dimerization of these adducts results in activation of p56lck in lipid rafts, where phosphatases are excluded. Additional cross-linking further increases p56lck kinase activity, induces translocation of TCR/CD3 and other signaling molecules to lipid rafts and intracellular calcium mobilization. These events are prevented by blocking Src kinases or CD8 binding to TCR-associated Kd molecules, indicating that CTL activation is initiated by cross-linking of CD8-associated p56lck. They are also inhibited by methyl-beta-cyclodextrin, which disrupts rafts and by dipalmitoyl phosphatidylethanolamine, which interferes with TCR signaling. Because efficient association of CD8 and p56lck takes place in rafts, both reagents, though in different ways, impair coupling of p56lck to TCR, thereby inhibiting the initial and essential activation of p56lck induced by cross-linking of engaged TCR.
Keywords
Animals, Antigens, CD3/metabolism, Antigens, CD8/metabolism, Antigens, Protozoan/immunology, Calcium/metabolism, Cells, Cultured, Cross-Linking Reagents, Cyclodextrins/pharmacology, Detergents, Dimerization, Enzyme Activation, Flow Cytometry, Humans, Lymphocyte Activation/drug effects, Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/metabolism, Macromolecular Substances, Membrane Microdomains/enzymology, Membrane Microdomains/metabolism, Palmitic Acid/metabolism, Plasmodium berghei/immunology, Protein Transport, Receptors, Antigen, T-Cell/metabolism, Signal Transduction, Solubility, T-Lymphocytes, Cytotoxic/cytology, T-Lymphocytes, Cytotoxic/drug effects, beta-Cyclodextrins
Pubmed
Web of science
Create date
28/01/2008 11:20
Last modification date
20/08/2019 13:10
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