While complement activation likely promotes the uptake of mycobacteria into macrophages [8, 17], deficiency of C5 resulted in enhanced susceptibility to TB and its associated trehalose 6,6′-dimycolate glycolipid; this was evident by a reduced IL-12 production by macrophages and reduced IFN-γ synthesis and production [6, 9]. Here, IFNG is linked to tuberculosis.