TNF and infection: TNF is a major proinflammatory cytokine induced by BCG infection and can be observed intracellularly (iTNF), on the cell surface as transmembrane (tmTNF) and in a soluble TNF form (sTNF) [22, 29–32]. In vivo, BCG infection has shown that tmTNF may interact with soluble TNF receptors (sTNFR1 or sTNFR2) which may play a critical role in the infection outcome [32].