Immunosenescence and cancer vaccines

Experimental and clinical data demonstrate that ageing is associated with the gradual deterioration of the immune system, generally referred to as immunosenescence. Age-related immune dysfunction may have an impact not only on the incidence of cancer, but also on the preventive and therapeutic approaches, which are based on immune system activation. Over the last few years the use of immunological measures to prevent cancer in experimental mouse models involving preimmunization with new vaccines against even a poor or apparently non-immunogenic tumour has yielded worse outcomes in older age than in young adults. Different mechanisms, which may be due to age-related numerical or functional dysfunction of immune cells and/or to tumour microenvironmental changes, could be responsible for this defect. This review summarises the impact of immunosenescence on the effectiveness of cancer vaccines, knowledge of cancer immunisation in old age and the potential mechanisms implicated in the poorer effectiveness of anticancer immune-based approaches in advanced age. Several approaches to, and possibilities of correcting the low effectiveness of immunisation procedures in old age are described.