Fig. 3— Malignant mesothelioma-infiltrating CD8+ T-cells are activated but lose cytotoxic lymphocyte (CTL) activity; tumours were also harvested from AE17-secreted ovalbumin (sOVA)-bearing mice given 5,6-carboxy-fluorescein-succinimidyl-ester (CFSE)-labelled, tumour antigen specific, OT-I T-cells (as per fig. 1b⇑ and c). a) The few OT-I cells that penetrated the tumour expressed low levels of CFSE similar to proliferating cells seen in mice given OVA in incomplete Freunds adjuvant draining lymph node (dLN), indicative of proliferation. However, the few CFSEhigh (OVA257–264 peptide SINFEKL) and CFSElow target cells harvested from the tumours of d) AE17-sOVA-bearing mice (as per fig. 1f⇑ and g) showed no in vivo CTL activity relative to c) the CTL activity in dLN of the same mouse. In separate experiments, tumours and dLN harvested from AE17-bearing mice were double stained for e) CD8 and CD69, f and g) interferon (IFN)-γ, h) CD25 and i) CD44. Fluorescence-activated cell sorter analysis was performed by gating on CD8+ cells. Representative histograms are shown with dLN and tumour overlaid for e) CD69, f) IFN-γ analysis in the dLN and g) tumour. e) ––––: tumour; ······: dLN. f and g) –––––: IFN-γ; ········: rat immunoglobulin G1 isotype control. These experiments were repeated twice (6 mice·group−1). Pooled data from two experiments (6 mice·group−1) is shown for h) CD25 and i) CD44 as mean±sem percentage of CD8 cells. ▪: normal LN; ▓: AE17; □: AE17-sOVA. **: p<0.01, comparing dLN with normal LN.