Programmed death 1 expression on HIV-specific CD4+ T cells is driven by viral replication and associated with T cell
Michelle D'Souza1, Andrew P Fontenot, Doug G Mack
1Department of Medicine, University of Colorado at Denver and Health Sciences Center, Denver, CO 80262, USA.
Journal of Immunology (Baltimore, Md. : 1950)
|July 21, 2007
Summary
Programmed death 1 (PD-1) is elevated on HIV-specific CD4(+) T cells during chronic infection, correlating with viral load. Blocking PD-1 may restore T cell function, offering a therapeutic target for HIV.
Area of Science:
- Immunology
- Virology
- T cell biology
Background:
- Chronic HIV infection leads to functional impairment of HIV-specific CD4(+) T cells, often attributed to T cell exhaustion.
- The programmed death 1 (PD-1) pathway is implicated in T cell dysfunction during chronic viral infections.
- PD-1 pathway blockade has shown promise in restoring HIV-specific T cell function.
Purpose of the Study:
- To investigate the role of PD-1 expression in the dysfunction of HIV-specific CD4(+) T cells during chronic HIV infection.
- To examine PD-1 expression levels on virus-specific CD4(+) T cells in relation to HIV replication and treatment status.
Main Methods:
- Measurement of PD-1 expression on T cells from blood and lymph nodes of HIV-infected individuals.
- Comparison of PD-1 expression on HIV-specific CD4(+) T cells versus total or CMV-specific CD4(+) T cells.
- Correlation analysis of PD-1 expression with plasma viral load and location (blood vs. lymph node).
Main Results:
- PD-1 expression was significantly higher on IFN-gamma-producing HIV-specific CD4(+) T cells compared to total or CMV-specific CD4(+) T cells in untreated subjects.
- PD-1 expression on HIV-specific CD4(+) T cells was significantly reduced in subjects receiving antiretroviral therapy.
- A direct correlation was observed between PD-1 expression on HIV-specific CD4(+) T cells and plasma viral load.
- PD-1 expression was higher on HIV-specific T cells in lymph nodes compared to blood.
Conclusions:
- PD-1 expression on HIV-specific CD4(+) T cells is driven by persistent HIV replication.
- Elevated PD-1 on these cells indicates a potential mechanism for T cell exhaustion in chronic HIV.
- Targeting the PD-1 pathway presents a potential strategy to enhance the functional capacity of HIV-specific CD4(+) T cells.
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