Response of Mtb to phagocytosis <i>Mtb</i> encounters a vastly changed environment, soon after it gets internalized by macrophages. The compartment it resides in, the phagosome, is acidified and devoid of important metal ions. It is flooded with reactive oxygen and nitrogen species. And steps will be soon taken by the macrophage to "mature" the phagosome with all kinds of lysosomal digestive enzymes. However, unlike most other bacteria species <i>Mtb.</i> has evolved solutions to each of these threats and, after making sure these are installed, it soon will enter a dormant state (de Chastellier, 2009; Flannagan et al, 2009). A combination of the host defense and the response of the infecting bacillus (active and passive) ensure suppression of bacterial metabolic activity and replication, resulting in a non-replicating state (Russell 2011, Russell et al. 2010). <br><br> Authored: Stephan, R, 2011-01-10 Edited: Jassal, B, 2011-02-28 GENE ONTOLOGYGO:0052572 Pubmed19261352 Pubmed19369951 Pubmed20466922 Pubmed21349098 Reactome Database ID Release 431222499 Reactome, http://www.reactome.org ReactomeREACT_121042 Reviewed: Warner, D, 2012-04-30 Tolerance by Mtb to nitric oxide produced by macrophages Tolerance of reactive oxygen produced by macrophages Cell redox homeostasis Mtb iron assimilation by chelation PathwayStep3796 PathwayStep3788 PathwayStep3813 PathwayStep3804