PDCD1LG2 and tuberculosis: In animal TB models, severe TB infection induces up-regulation of genes involved in Th1 and Th17 responses, and tissue overexpression of IL-22, MIP-1α, CCL27, IP-10, CCR4, CCR5, CXCR3, PD-1, PDL-2, IL-3, IFN-β, TIM-1, and TLR-2 associated with low TB-specific cellular responses (18).