Quantifying Antigen-Specific T Cell Responses When Using Antigen-Agnostic Immunotherapies

Abstract

Immunotherapies are at the forefront of the fight against cancers, and researchers continue to develop and test novel immunotherapeutic modalities. Ideal cancer immunotherapies induce a patient’s immune system to kill their own cancer and develop long-lasting immunity. Research has demonstrated a critical requirement for CD8+ and CD4+ T cells in achieving durable responses. In the path to the clinic, researchers require robust tools to effectively evaluate the capacity for immunotherapies to generate adaptive anti-tumor responses. To study functional tumor-specific T cells, researchers have relied on targeting tumor-associated antigens (TAAs) or the inclusion of surrogate transgenes in pre-clinical models, which facilitate detection of T cells by using the targeted antigen(s) in peptide re-stimulation or tetramer-staining assays. Unfortunately, many pre-clinical models lack a defined TAA, and epitope mapping of TAAs is costly. Surrogate transgenes can alter tumor engraftment and influence the immunogenicity of tumors, making them less relevant to clinical tumors. Further, some researchers prefer to develop therapies that do not rely on pre-defined TAAs. Here, we describe a method to exploit major histocompatibility complex expression on murine cancer cell lines in a co-culture assay to detect T cells responding to bulk, undefined, tumor antigens. This is a tool to support the preclinical evaluation of novel, antigen-agnostic immunotherapies.

Tumour neoantigen mimicry by microbial species in cancer immunotherapy

“…Although surrogate tumour antigen models can provide unique opportunities to track antigen-specific immune responses (which is important for initial proof-of-concept studies), 123 , 124 they are largely artificial and can have limited predictive and translational value. 125 , 126 Conversely, tumour neoantigens from mutagen-induced (e.g. dimethylbenzathracene, azoxymethane, N -ethyl- N -nitrosourea, UV light 127 ) or genetically-engineered tumours (e.g.…”

Combining vanadyl sulfate with Newcastle disease virus potentiates rapid innate immune-mediated regression with curative potential in murine cancer models

“…Tumor-specific T cells in the blood are then detected by flow cytometry after co-culture, as described. 37 The second assay we employed identified CD8 + T cells specific for the melanoma-associated dopachrome tautomerase 180-188 peptide that is expressed by B16-F10 cells and is the dominant epitope for cytotoxic T cells in C57BL/6 mice. Regardless of the assay, none of the treatments significantly increased the number of B16-F10-specific CD8 + T cells in the blood (Figures 3D and 3E).…”

Mechanisms that allow vaccination against an oncolytic vesicular stomatitis virus-encoded transgene to enhance safety without abrogating oncolysis

“…These T cells were co-cultured with various ratios of B16-F10 melanoma cells that had been pre-treated for 24 h with recombinant interferon-gamma (BioLegend, cat. #575308) to upregulate the expression of major histocompatibility complex molecules to facilitate antigen presentation 58 . In parallel, a second set of co-cultured cells were tested in which the number of effector cells were reduced fourfold.…”