IL15 and cancer: Furthermore, in the context of cancer immunotherapy, IL-15 has been shown to restore the anti-tumour cytotoxicity of anergic CD8+ T cells against injected erythroleukaemia cell lines in mice in vivo (198) and to restore interferon (IFN)-γ production by Wilms’ tumour antigen-specific T cells ex vivo in patients with Wilms’ tumour antigen-expressing prostate cancer (199).