Neoantigen landscape dynamics during human melanoma-T cell interactions

Area of Science:

• Immunology
• Oncology
• Genetics

Background:

• Neoantigens, arising from DNA damage, are crucial targets for cancer immunotherapies like T-cell checkpoint blockade and adoptive T-cell therapy.
• Tumor antigenicity can be altered by T-cell pressure, potentially leading to the loss of recognized mutant antigens in preclinical models.
• The stability of neoantigen-specific T-cell responses and their targets in human cancers over time remains largely uncharacterized.

Purpose of the Study:

• To investigate the stability of neoantigen-specific T-cell responses and the antigens they recognize in patients with advanced melanoma undergoing adoptive T-cell transfer.
• To understand the dynamic interplay between tumor cells and T cells in the context of neoantigen recognition and potential immune escape mechanisms.

Main Methods:

• Analysis of neoantigen-specific T-cell responses and their recognized antigens in two patients with stage IV melanoma.
• Assessment of changes in tumor cell populations, including gene expression and mutant allele loss, related to T-cell-recognized neoantigens.
• Evaluation of T-cell reactivity within tumor-infiltrating lymphocytes in response to neoantigen loss.

Main Results:

• T-cell-recognized neoantigens were selectively lost from the tumor cell population in the studied patients.
• Neoantigen loss occurred through reduced gene expression or loss of mutant alleles.
• The loss of neoantigens was associated with the development of neoantigen-specific T-cell reactivity within tumor-infiltrating lymphocytes.

Conclusions:

• T cells mediate a form of neoantigen immunoediting, dynamically interacting with cancer cells.
• Tumor cells can evade T-cell recognition by losing target neoantigens.
• Therapeutic strategies should aim to induce broad neoantigen-specific T-cell responses to overcome tumor resistance and prevent immune escape.