We have demonstrated that although WSX-1 signalling modulates the expression of multiple stimulatory and inhibitory receptors on Th1 cells during infection, including PD-1 and BTLA, individual neutralisation of IL-12p40 from day 7 of infection was sufficient to prevent aberrant T–bet expression, abrogate the development of terminally differentiated KLRG-1+ Th1 cells and attenuate T-cell dependent immunopathology in malaria infected WSX-1−/− mice. Here, BTLA is linked to malaria.