Apoptotic death concurrent with CD3 stimulation in primary human CD8+ T lymphocytes: a role for endogenous granzyme B
| Autor: | Anna Senik, Sylvie Carmona, Nicolas Bidère, Aurore Devocelle, Bernard Charpentier, Mireille Laforge |
|---|---|
| Přispěvatelé: | INSERM U542, Hôpital Paul Brousse |
| Rok vydání: | 2006 |
| Předmět: |
CD4-Positive T-Lymphocytes
Cell Extracts Pore Forming Cytotoxic Proteins CD3 Complex CD3 [SDV]Life Sciences [q-bio] Immunology Down-Regulation Apoptosis CD8-Positive T-Lymphocytes Antibodies Granzymes 03 medical and health sciences 0302 clinical medicine Cytosol Immunology and Allergy Humans RNA Small Interfering ComputingMilieux_MISCELLANEOUS Cells Cultured Serpins 030304 developmental biology 0303 health sciences Membrane Glycoproteins Microscopy Confocal biology Caspase 3 Perforin T-cell receptor Serine Endopeptidases Molecular biology Cathepsins Cell biology Mitochondria Granzyme B Protein Transport Granzyme Caspases biology.protein Apoptotic signaling pathway hormones hormone substitutes and hormone antagonists CD8 030215 immunology BH3 Interacting Domain Death Agonist Protein Protein Binding |
| Zdroj: | Journal of Immunology Journal of Immunology, Publisher : Baltimore : Williams & Wilkins, c1950-. Latest Publisher : Bethesda, MD : American Association of Immunologists, 2006, 176 (7), pp.3966-3977. ⟨10.4049/jimmunol.176.7.3966⟩ |
| ISSN: | 0022-1767 1550-6606 |
| DOI: | 10.4049/jimmunol.176.7.3966⟩ |
| Popis: | We exposed primary CD8+ T cells to soluble CD3 mAb plus IL-2 and limited numbers of monocytes (3%). These cells were activated but concurrently subjected to ongoing apoptosis (∼25% were apoptotic from day 2 of culture). However, their costimulated CD4+ counterparts were much less prone to apoptosis. The apoptotic signaling pathway bypassed Fas and TNFRs, and required the activity of cathepsin C, a protease which performs the proteolytic maturation of granzyme (Gr) A and GrB proenzymes within the cytolytic granules. Silencing the GrB gene by RNA interference in activated CD8+ T cells prevented the activation of procaspase-3 and Bid, and indicated that GrB was the upstream death mediator. A GrB-specific mAb immunoprecipitated a ∼70-kDa molecular complex from cytolytic extracts of activated CD8+ (but not resting) T cells, that was specifically recognized by a nucleocytoplasmic protease inhibitor 9 (PI-9) specific mAb. This complex was also detected after reciprocal immunoprecipitation of PI-9. It coexisted in the cytosol with the 32-kDa form of GrB. As neither were detected in the cytosol of CD4+ bystander T cells (which poorly synthesized GrB), and as silencing the perforin (Pf) gene had no effect in our system, endogenous GrB was likely implicated. Immunoprecipitation experiments failed to reveal Pf in the cytosol of CD8+ T cells, and only a tiny efflux of granular GrA was detected by ELISA. We propose that some GrB is released from cytolytic granules to the cytosol of CD8+ T lymphocytes upon CD3/TCR stimulation and escapes PI-9, thereby mediating apoptotic cell death. |
| Databáze: | OpenAIRE |
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