Immunological monitoring of cancer vaccine therapy

Immunological treatment of malignant diseases in humans aiming at the induction and proliferation of antigen-specific T cells has made rapid progress in recent years. A growing number of tumour-associated antigens, potentially synergistic combinations with adjuvants, and various routes of application provide new opportunities for cancer vaccination. Therefore, a highly accurate assessment of vaccine-induced T cell responses is required. Three T cell assays (tetramers, intracellular cytokine flow cytometry and ELISPOT assay) have emerged as first-line methods for monitoring T cell induction during vaccination. These assays are relatively easy to perform, reliable, sensitive and allow an ex vivo T cell analysis at the single cell level. Although at this stage assays are not a defined surrogate marker for clinical efficacy, they already provide information concerning the immunological potency of a given vaccine. In particular, comparing immune responses under various treatment conditions will help to develop more clinically efficient tumour vaccination. Novel assays, such as CD107 staining, human leukocyte antigen/green fluorescent protein-antigen-presenting cells or microarrays, and assays determining functions, such as proliferation assays, are beginning to complement first-line monitoring assays.