Cancer vaccination at older age

Cancer vaccination is less effective at old than at young age, due to T cell unresponsiveness. This is caused by various age-related changes of the immune system, such as lack of naïve T cells, defects in activation pathways of T cells and antigen-presenting cells, and age-related changes in the tumor microenvironment. Natural killer, natural killer T cells, and γδT cells of the innate immune system also change with age but these responses may be more susceptible for improvement than adaptive immune responses at older age. This chapter compares various studies involving adaptive and innate immune responses in elderly and cancer patients, as well as cancer vaccination at young and old age. Finally, potential new directions in cancer vaccination at older age are discussed.