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Surface-bound Tat inhibits antigen-specific CD8+ T-cell activation in an integrin-dependent manner.
Aids 28, 2189-2200 (2014)
OBJECTIVE:: The identification of still unrevealed mechanisms affecting the anti-HIV CD8 T-cell response in HIV-1 infection. DESIGN:: Starting from the observation that anti-Tat immunization is associated with improved CD8 T-cell immunity, we developed both in-vitro and ex-vivo assays to characterize the effects of extra-cellular Tat on the adaptive CD8 T-cell response. METHODS:: The effects of Tat on CD8 T-cell activation were assayed using CD8 T-cell clones specific for either cellular (MART-1) or viral (HIV-1 Nef) antigens, and HIV-1 Gag-specific CD8 T cells from HIV-1 patients. RESULTS:: The interaction between CD8 T lymphocytes and immobilized Tat, but not its soluble form, inhibits peptide-specific CD8 T-lymphocyte activation. The inhibition does not depend on Tat trans-activation activity, but on the interaction of the Tat RGD domain with α5β1 and αvβ3 integrins. Impaired CD8 T-cell activation was also observed in cocultures of CD8 T cells with HIV-1-infected cells. Anti-Tat Abs abrogate the inhibitory effect, consistently with the evidence that extracellular Tat accumulates on the cell membrane of virus-producing cells. The Tat-induced inhibition of cell activation associates with increased apoptosis of CD8 T cells. Finally, the inhibition of cell activation also takes place in Gag-specific CD8 T lymphocytes from HIV-1-infected patients. CONCLUSION:: Our results support the idea that CD8 T-cell apoptosis induced by surface-bound extracellular Tat can contribute to the dysregulation of the CD8 T-cell adaptive response against HIV as well as other pathogens present in AIDS patients.
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Publication type
Article: Journal article
Document type
Scientific Article
Keywords
Apoptosis ; Cd8(+) T Cells ; Interferon-gamma ; Integrins ; Tat; Immunodeficiency-virus Type-1; Fibroblast-growth-factor; Heparan-sulfate Proteoglycans; Hiv-1 Tat; Immune-response; Kaposis-sarcoma; Dendritic Cells; Protein; Infection; Aids
Language
english
Publication Year
2014
HGF-reported in Year
2014
ISSN (print) / ISBN
0269-9370
e-ISSN
1473-5571
Journal
AIDS
Quellenangaben
Volume: 28,
Issue: 15,
Pages: 2189-2200
Publisher
Lippincott Williams & Wilkins
Publishing Place
Philadelphia
Reviewing status
Peer reviewed
Institute(s)
Institute of Molecular Immunology (IMI)
POF-Topic(s)
30504 - Mechanisms of Genetic and Environmental Influences on Health and Disease
Research field(s)
Immune Response and Infection
PSP Element(s)
G-501790-002
PubMed ID
25313583
WOS ID
WOS:000342231900002
Scopus ID
84927734771
Erfassungsdatum
2014-10-16