Measuring the Antitumor T-Cell Response in the Context of Photodynamic Therapy

The field of photodynamic therapy (PDT) of cancer, like oncology research in general, is showing increasing interest in tumor immunology and immune effects of tumor treatment. Tumor ablation by PDT can lead to strong shifts in the composition of the immune cell infiltrate of tumors, and systemic effects of local therapy have been described. T lymphocytes, also known as T cells, are a type of adaptive immune cells that are of particular interest as they are very efficient in target cell recognition and killing, both at the treatment site and systemically. Moreover, T cells can constitute immunological memory to provide long-term protection. Several studies have described in detail how T-cell immune responses are induced by PDT and can play an important role in the therapeutic effect. This chapter describes several approaches of the analysis of T-cell responses during or after PDT in a mouse tumor model.