IFNG and tuberculosis: The notion that complex mechanisms beyond Th1 immunity are at play in TB immunity is supported by (1) the unsatisfactory results of vaccine strategies aimed at boosting Th1 immunity in TB patients (31); (2) the inflammatory damage associated with increasing IFN-γ production by T-cells in the lungs of Mtb-infected mice (33); and (3) the host-detrimental effect of targeting the Th1-inhibiting PD1/PD-L1 interaction in mice (34, 35).