No abstract

SUMMARY Decreased human immunodeficiency virus (HIV)-specific CD8+ T cell proliferation is a hallmark of chronic infection, but the mechanisms of decline are unclear. We analyzed gene expression profiles from antigen-stimulated HIV-specific CD8+ T cells from patients with controlled and uncontrolled infection and identified caspase-8 as a correlate of dysfunctional CD8+ T cell proliferation. Caspase-8 activity was upregulated in HIV-specific CD8+ T cells from progressors and correlated positively with disease progression and programmed cell death-1 (PD-1) expression, but negatively with proliferation. In addition, progressor cells displayed a decreased ability to upregulate membrane-associated caspase-8 activity and increased necrotic cell death following antigenic stimulation, implicating the programmed cell death pathway necroptosis. In vitro necroptosis blockade rescued HIV-specific CD8+ T cell proliferation in progressors, as did silencing of necroptosis mediator RIPK3. Thus, chronic stimulation leading to upregulated caspase-8 activity contributes to dysfunctional HIV-specific CD8+ T cell proliferation through activation of necroptosis and increased cell death.

The goal of the is project was to further define our understanding of the critical antiviral effector molecules and cell signaling pathways involved in CD8 T cell mediated control of HIV infection.