High-throughput monitoring of human tumor-specific T-cell responses with large peptide pools

Abstract

In immune intervention trials, the comprehensive investigation of immunogenicity or T-cell epitope-mapping is challenging especially when a large set of epitopes needs to be screened and limited sample material is available. To this end, T-cell responses are often monitored using peptide pools. Here, we assessed the magnitude and sensitivity of detection of antigen-specific CD8 C and CD4 C T cells using a single peptide alone or mixed into large pools. Interestingly the magnitude of ex vivo anti-viral and anti-tumor T-cell responses was identical irrespective of the presence and number of irrelevant peptides, in different functional assays with PBMCs from healthy donors and cancer patients. Moreover, the presence of up to 300 irrelevant peptides did not affect the threshold of responsiveness of antigen-specific CD8 C T cells to single cognate peptides. These data demonstrate the relevance of using very large peptide pools for the sensitive and specific immune-monitoring of epitope-specific T cells in natural or immunemodulated context.

CD4 T cells target colorectal cancer antigens upregulated by oxaliplatin

“…Among immune responders, 18% and 21% of oxaliplatin‐treated patients respond solely to COA‐1 and mesothelin peptides, respectively. These results encourage the development of immunotherapy targeting both COA‐1, mesothelin and TERT peptides and the use of a large peptide pool for high‐throughput monitoring …”

Rapid selection and identification of functional CD8+ T cell epitopes from large peptide-coding libraries

“…These configurations all have in common the requirement to load target cell populations with individual candidate antigens and test each of them for T-cell recognition “one-by-one” in separate reactions. Pooling strategies can increase the search space, but would, subsequently, need to be laboriously deconvoluted 11–13 . Thus, functional cellular assays have yet to be scaled in a manner that could conceivably enable exhaustive screening of large sets of potential epitopes, such as those spanning an entire proteome.…”

PRAME peptide‐specific CD8+ T cells represent the predominant response against leukemia‐associated antigens in healthy individuals

“…Even though the consensus length for peptides binding pMHC class I molecules is notably shorter spanning 8‐11 amino acids, a full CD8 response can be induced by mechanisms accommodating longer peptides in the binding site by bulging or protrusion . The presence of irrelevant peptides in a peptide pool does not affect the magnitude of a response by CTLs to their cognate epitopes .…”