With this chemical fixation strategy in hand, we checked the ability of M. tuberculosis strains to induce a change in EGSH of U937 monocytes by infecting these cells harboring cytosolic Grx1-roGFP2 at a multiplicity of infection of 10 (10 bacteria/macrophage) and measuring EGSH at 48 h post-infection. The gene discussed is GLRX; the disease is infection.