Reduced expression of major phagocytic and antimycobacterial proteins in Sphk-1 knockdown macrophages clearly indicated their poor innate immune defense against mycobacteria, which rendered these macrophages sensitive to infection, Reduced activation of the RelA subunit (pp65) of NF-κB in Sphk-1 knockdown and infected WT macrophages further suggested a possible regulation of Sphk-1 of both NF-κB itself and NF-κB mediated signaling (iNOs proteins, NO generation, TNF secretion and LAMP-2), which are important and involved in mycobacterial killing in macrophages [21]. Here, TNF is linked to infection.