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Nonproliferating bystander CD4+ T cells lacking activation markers support HIV replication during immune activation
1Division of Infectious Diseases and Center for AIDS Research, University of Pennsylvania, Philadelphia, PA 19104, USA.
Journal of Immunology (Baltimore, Md. : 1950)
|May 9, 2001
Summary
Human immunodeficiency virus (HIV) unexpectedly replicates in non-activated bystander CD4(+) T cells during antigen-driven activation. Activated T cells showed protection, impacting HIV reservoir eradication and therapy strategies.
Area of Science:
- Immunology
- Virology
- Cell Biology
Background:
- Immune activation is a key driver of human immunodeficiency virus (HIV) replication in lymphoid tissues.
- Understanding which cells harbor HIV during immune responses is crucial for therapeutic strategies.
Purpose of the Study:
- To identify the specific CD4(+) T cell populations responsible for HIV replication during antigen (Ag)-driven T cell activation.
- To investigate the role of T cell activation status and chemokine receptor expression in HIV infection.
Main Methods:
- Utilized a novel in vitro model involving dendritic cell presentation of superantigen to CD4(+) T cells.
- Analyzed HIV replication in proliferating versus nonproliferating CD4(+) T cells.
- Assessed expression of activation markers and chemokine receptors (CCR5, CXCR4) on infected cells.
Main Results:
- HIV replication predominantly occurred in nonproliferating bystander CD4(+) T cells lacking activation markers.
- Activated, Ag-specific T cells were relatively protected from HIV infection.
- This protection correlated with down-regulation of CCR5 and CXCR4 chemokine receptors.
Conclusions:
- HIV replication is not limited to highly activated, Ag-specific CD4(+) T cells.
- Non-activated bystander cells are significant sites of HIV replication during immune activation.
- Findings have implications for HIV therapy, viral reservoir eradication, and understanding immune defects.