CD160 and PD-1 co-expression on HIV-specific CD8 T cells defines a subset with advanced dysfunction

Area of Science:

• Immunology
• Virology
• Cellular Biology

Background:

• Chronic viral infections, like HIV, cause persistent CD8 T cell activation and exhaustion.
• Programmed cell death-1 (PD-1) is linked to CD8 T cell dysfunction in HIV.
• CD160, a negative regulator of T cell activation, is also upregulated during chronic HIV infection.

Purpose of the Study:

• To investigate the role of CD160 in HIV-specific CD8 T cell exhaustion.
• To characterize CD8 T cell subsets expressing CD160 and PD-1.
• To evaluate the therapeutic potential of targeting the CD160-HVEM interaction.

Main Methods:

• Flow cytometry to identify CD8 T cell subsets expressing CD160 and PD-1.
• Functional assays measuring T cell proliferation and cytokine production.
• Transcriptional profiling of CD8 T cell subsets.
• Blocking assays targeting the CD160-HVEM interaction.

Main Results:

• Co-expression of CD160 and PD-1 on CD8 T cells identifies a functionally exhausted subset.
• CD160(-)PD-1(+) cells retain an activated phenotype, while CD160(+)PD-1(+) cells exhibit exhaustion markers.
• Blocking CD160-HVEM interaction restores HIV-specific CD8 T cell proliferation and cytokine production.
• Transcriptional analysis reveals downregulation of NFκB and upregulation of T cell inhibitors in CD160(+)PD-1(+) cells.

Conclusions:

• CD160 and PD-1 expression effectively distinguishes between activated and exhausted CD8 T cells in chronic HIV infection.
• Targeting the CD160 pathway, alongside PD-1, may be crucial for restoring CD8 T cell function.
• Multifaceted therapeutic approaches are necessary to overcome T cell exhaustion in chronic viral infections.