CD8+ TCR Bias and Immunodominance in HIV-1 Infection

Area of Science:

• Immunology
• Virology
• Genetics

Background:

• Immunodominance dictates that the immune system targets only a subset of pathogen-derived antigens.
• CD8(+) T cell responses, governed by HLA class I, exhibit constrained epitope targeting linked to disease progression.
• Factors controlling in vivo immunodominance remain largely unknown.

Purpose of the Study:

• To analyze CD8(+) T cell responses restricted by HLA-B*42:01 in HIV-1 infection.
• To identify mechanisms governing epitope-targeting frequency and antiviral efficacy.
• To investigate the role of T cell receptor (TCR) usage in immunodominance.

Main Methods:

• Extensive analysis of CD8(+) T cell responses against 20 epitopes restricted by HLA-B*42:01.
• Assessment of the association between Gag-specific responses, targeting breadth, and viral load set-points.
• Evaluation of peptide-HLA binding affinity and stability in relation to targeting frequencies.
• Correlation analysis between immunodominance and the usage of public TCRs (shared TRB sequences).

Main Results:

• A distinct immunodominance hierarchy was observed for HLA-B*42:01-restricted epitopes.
• Gag-specific responses and broader targeting correlated with lower viral loads.
• Peptide-HLA binding affinity and stability did not significantly predict targeting frequencies.
• Immunodominance strongly correlated with the use of public TCRs.

Conclusions:

• Shared TCR recruitment via public TCRs may be a key driver of immunodominance.
• This finding offers insights into the link between TCR usage, immunodominance, and antiviral efficacy in HIV-1.
• Understanding immunodominance mechanisms is crucial for developing effective T cell-based immunotherapies.