Early changes in peripheral blood T cells during primary infection of rhesus macaques with a pathogenic SIV |
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Authors: | Jé rô me Estaquier,Valé rie Monceaux,Marie-Christine Cumont,Anne-Marie Aubertin,Bruno Hurtrel,& Jean Claude Ameisen |
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Affiliation: | INSERM EMI 9922, Hôpital Bichat-Claude Bernard, UniversitéParis VII, 75877 Paris, France;;Institut Pasteur, 75724 Paris, France;;INSERM U74, UniversitéL. Pasteur, 67000 Strasbourg, France |
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Abstract: | Primary infection of rhesus macaques with pathogenic strains of simian immunodeficiency virus (SIV) leads to rapid and dynamic changes in both viral load and T cell counts in the peripheral blood. We have performed a sequential analysis of peripheral blood CD4 and CD8 T cells in five macaques during the 8 weeks following SIVmac251 infection. We observed a transient lymphopenia of both CD4 and CD8 T cells during the first 2 weeks, followed by a rebound. The primary phase of infection was associated with changes in the T cells expressing CD25, CD69, or HLA-DR and with a priming of the peripheral blood CD4 and CD8 T cells for a process of apoptosis in vitro that was enhanced by CD95 (Fas) ligation, and was detected in two macaques as early as 7 days after infection. Despite the small numbers of animals studied, the importance of the early transient CD4 and CD8 T lymphopenia was positively correlated with the viral load. No correlation was found, however, between the level of activation markers expressed or of priming for apoptosis in peripheral blood T cells and the viral load. Our findings suggest the possibility that the early activation and priming for apoptosis of CD4 and CD8 T cells may involve indirect, host-related, mechanisms, or alternatively, that the T cells that remain in the peripheral blood during primary infection do not adequately reflect the viral-mediated changes in T cell activation and death that may occur in the lymphoid organs throughout the body. |
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Keywords: | apoptosis caspase cytokine depletion Fas (CD95) |
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