MKI67 and infection: Ablation of WSX-1 signalling did not significantly affect the level of intrahepatic CD4+ T cell proliferation or apoptosis; intrahepatic CD4+ T cell expression of Ki67 and BrdU uptake was similar in WSX-1−/− and WT mice and there were no differences in expression of Annexin V or 7-AAD on either day 7 or day 14 of infection (Fig. 1D–G).