Comprehensive Evaluation of the Expressed CD8+ T Cell Epitope Space Using High-Throughput Epitope Mapping

Area of Science:

• Immunology
• Virology
• Molecular Biology

Background:

• Traditional T cell immunity assays rely on functional recall or peptide-specific T cell receptor binding.
• Incorrect antigen or peptide selection can lead to underestimated T cell responses or false negatives in immune monitoring.

Purpose of the Study:

• To highlight the critical importance of selecting the correct antigens and peptides for accurate T cell immune monitoring against human cytomegalovirus (HCMV).
• To demonstrate the inadequacy of commonly used epitopes for detecting CD8+ T cell immunity against HCMV.

Main Methods:

• Systematic assessment of T cell reactivity against individual nonamer peptides derived from the HCMV pp65 protein.
• High-throughput ELISPOT-based "brute force" epitope mapping for genome-wide peptide testing.

Main Results:

• Individual HCMV antigens and previously reported epitopes often failed to detect CD8+ T cell immunity in subjects.
• Systematic testing against all potential epitopes encoded by an antigen's genome is necessary for reliable CD8+ T cell immunity detection.

Conclusions:

• Reliable detection of T cell immunity necessitates comprehensive epitope screening.
• High-throughput methods enable large-scale, systematic peptide mapping for robust immune monitoring against complex viral systems like HCMV.