Isolation and Expansion of Tumor-Specific CD4+T-Cells by Means of Cytokine Secretion

A major objective of immune analysis in the setting of cancer, cancer vaccination, and therapy is to accurately characterize and isolate functional T-cells elicited by a tumor. Secretion of cytokines is an important function of activated effector and memory T-cells. The cytokine secretion assay (CSA) directly assesses T-cells secreting cytokines after a short restimulation in vitro. Cells can be stained for surface markers enabling characterization of subsets. Viable cytokine-secreting T-cells can be isolated for expansion and further functional testing or adoptive transfer. Since the method is not restricted to any antigen or major histocompatibility complex (MHC) haplotype, it enables us to detect CD8⁺ as well as CD4⁺ T-cells reacting against a wide vary of tumor-associated antigens, ranging from particular known tumor antigens to whole tumor cells and crude tumor lysates. Thus, the method provides a valuable tool to analyze and isolate functional tumor-responsive T-cells according to one of their effector functions.