Quantification and functional assessment of antigen(-) tumor cell variants

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• T-cell redirecting therapies, including CAR T cells and bispecific antibodies, are advanced cancer immunotherapies.
• These therapies exert selective pressure, potentially enriching for antigen-negative (Ag^low/-) tumor cell variants resistant to treatment.
• Antigen escape, driven by pre-existing Ag^low/- cells, is a major cause of clinical relapse and a significant challenge in cancer treatment.

Purpose of the Study:

• To describe a novel approach for quantifying and functionally assessing antigen-negative (Ag^-) tumor cells.
• To enable high-throughput screening of single-cell samples (biopsy or PBMCs) for Ag^- cell populations.
• To provide a straightforward in vitro assay for evaluating the targeting propensity of Ag^- cells.

Main Methods:

• Development of a method to quantify antigen-negative tumor cells.
• Application of the method to single-cell biopsy or peripheral blood mononuclear cell (PBMC) samples.
• In vitro assay design for assessing the susceptibility of Ag^- cells to immune targeting.

Main Results:

• The described approach allows for the quantification and functional assessment of antigen-negative tumor cells.
• The method facilitates high-throughput screening of various sample types.
• The assay provides a straightforward assessment of Ag^- cell targeting propensity.

Conclusions:

• The developed method offers a valuable tool for studying antigen escape mechanisms in cancer immunotherapy.
• This approach can be adapted for samples from different anatomical sites and integrated with extensive flow cytometry phenotyping.
• Quantifying and assessing Ag^- cells is crucial for overcoming treatment resistance and improving patient outcomes in cancer immunotherapy.