TBX21 and infection: Lung γδT cell (Fig 6F) and IFN-γ producing γδT cell (Fig 6G) number was not significantly different in PBS challenged Tbet-/- vs. w/t mice, but again failed to increase following infection in Tbet-/- mice, such that total and IFN-γ+ γδT cell number was higher in RV infected w/t vs. RV infected Tbet-/- mice.