How to analyze ex vivo T-cell responses in cancer patients

Tumor-associated antigens are present in several malignancies and represent promising targets for immunotherapeutic approaches. Antigen-specific CD8+ T-cells are an important component of immunosurveillance in malignant diseases as they recognize, target, and kill tumor cells. The induction of T-cells reactive against epitopes of tumor-associated antigens is the major immunological aim of several cancer vaccination trials. In recent years, significant progress has been made in developing methods to detect and characterize these antigen-specific T-cells. Here, we review and compare the most important techniques for specific T-cell analyses including cytokine-based functional assays, HLA class I/epitope tetrameric complexes, and PCR-based methods. We emphasize single cell methods and underline the importance of ex vivo methods without prior culturing.