As anti-IL-12p40 mAbs inhibit T-bet expression and Th1 cell differentiation in the spleen of malaria-infected WSX-1−/− mice [14], where the hepatotropic cells likely originate (16), we hypothesised that suppressing Th1 responses in WSX-1−/− mice by administering anti-IL-12p40 mAbs would significantly attenuate CD4+ T cell accumulation in the livers of WSX-1−/− mice during malaria infection. Here, CD4 is linked to malaria.