(a) LCMV-specific CD8+ T cells in the blood (day 8) of MOPC-tumour-bearing or control mice, which where infected with LCMV (n=3). (b) Expression of PD-1, IL-2Rβ and IL-7Rα on tumour-specific CD8+ T cells (OT1, day 8) of B16-OVA-tumour-bearing C57BL/6 mice (day −10) transferred with 5 × 106 OT1 splenocytes (day −1) and additionally treated with (n=5) or without (n=3) LCMV (i.t. 2 × 104 PFU). (c) Total numbers of tumour-specific (OVA), antigen-exposed (CD44+) CD8+ T cells (day 2) in tumours of B16-OVA-tumour-bearing C57BL/6 mice (day −13), which were vaccinated with ovalbumin (200 μg, day −3, i.v.) with or without CpG (20 μg, day −3, i.v.) and additionally treated with or without LCMV (5 × 105 PFU, i.t., n=8). (d) Tumour diameter and survival of B16-OVA-tumour-bearing C57BL/6 mice (day −10) treated with (n=5 per group) or without (n=4 per group) 5 × 106 OT1 splenocytes (day −1) and additionally treated with or without LCMV (i.t. 2 × 104 PFU). (e) Tumour diameter and survival of EL4-OVA-lymphoma-bearing C57BL/6 mice (day −6) treated with (n=7 per group) or without (n=4–5 per group) 5 × 106 OT1 splenocytes (day −1) and additionally treated with or without LCMV (i.t. 2 × 106 PFU, day 0). Data are shown as mean±s.e.m. and analysed by unpaired Student's t-test. NS, nonsignificant; *P<0.05, **P<0.01 and ***P<0.001.