Anergy and apoptosis in CD8+ T cells from HIV-infected persons
| Autor: | D E Lewis, D S Tang, A Adu-Oppong, W Schober, J R Rodgers |
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| Rok vydání: | 1994 |
| Předmět: | |
| Zdroj: | The Journal of Immunology. 153:412-420 |
| ISSN: | 1550-6606 0022-1767 |
| DOI: | 10.4049/jimmunol.153.1.412 |
| Popis: | CD8+T cells from HIV-infected persons increase early in infection, display increased levels of activation Ags, and abnormal MHC-restricted, HIV-specific and nonspecific cytotoxicity abilities. Paradoxically, these cells are also unresponsive to T cell signaling in vitro and have decreased in vitro cloning potential. HIV-specific CTL precursors also are lost late in infection. A quantitative Southern blotting technique showed that CD8+ T cells from asymptomatic, HIV-infected persons have increased DNA fragmentation after overnight incubation. DNA fragmentation was reduced by an endonuclease inhibitor but not by cycloheximide, suggesting that a pre-apoptotic state exists in vivo. Partial inhibition of DNA fragmentation also could be induced by IL-2 addition. No consistent difference in fragmentation was observed among CD8+ subpopulations from HIV-infected individuals, although only CD8+ T cells that did not express activation Ags (DR-, CD28+, CD57- phenotype) showed reduced fragmentation when incubated in IL-2. A dramatic increase in CD8+, CD28- cells was observed in asymptomatic HIV-infected people. A subset of CD8+, CD28- cells in both controls and HIV-infected people do not proliferate to T cell signals, and these cells from controls demonstrate increased DNA fragmentation in vitro after 3 days of incubation, regardless of stimulation conditions. This suggests that the cells are end-stage cells. Taken together, the data suggest an increase in anergic or apoptotic CD8+ T cells in HIV-infected persons. Eventual depletion of HIV-specific CD8+ T cells may occur through a process of proliferation, anergy induction, and apoptosis. |
| Databáze: | OpenAIRE |
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