High-throughput Screening of Human Tumor Antigen-specific CD4 T Cells, Including Neoantigen-reactive T Cells

Area of Science:

• Immunology
• Oncology
• T-cell biology

Background:

• Characterizing CD4 T-cell responses to tumor antigens is crucial for cancer immunotherapy.
• Existing methods for detecting antigen-specific T cells can be limited by throughput and HLA dependency.

Purpose of the Study:

• To develop and validate a high-throughput, HLA-independent method for screening tumor antigen- and neoantigen-specific CD4 T cells.
• To estimate precursor frequencies and functionally characterize these T cells in healthy donors and cancer patients.

Main Methods:

• Utilized an in vitro amplified T-cell library screening procedure.
• Employed a high-throughput, human leukocyte antigen (HLA)-independent approach for frequency estimation.
• Isolated and functionally characterized tumor-reactive CD4 T-cell clones.

Main Results:

• Identified comparable frequencies of naive tumor-associated antigen (TAA)-specific CD4 T cells in healthy donors as those specific for infectious agents.
• Detected low but consistent numbers of memory CD4 T cells specific for TAAs in healthy donors.
• Observed increased TAA-specific CD4 T cells in melanoma patients after immunotherapy, detectable within tumors and exhibiting polyfunctionality.

Conclusions:

• The developed screening method is simple, noninvasive, and requires minimal biological material.
• This HLA class II-independent approach facilitates the screening of numerous tumor antigens, including neoantigens.
• The method will accelerate immunomonitoring and the development of CD4 T-cell-based cancer therapies.