IL1B and neoplasm: To understand whether CTLs induce IL-1β production during antigen-specific antitumour immunity, we established an in vivo model in which mice were injected subcutaneously (s.c.)with the tumour cell line EL4 (a T-cell-derived tumour cell line) or OVA containing EL4 (EG7) for tumour formation, and then injected intravenously (i.v.)with activated OT1 CTLs to kill EG7 target cells (as depicted in Supplementary Fig. 5a).