2.5. THP-1 Macrophage Infection and Treatment

Differentiated macrophages were infected with processed M. tb at a multiplicity of infection or MOI (multiplicity of infection) of 0.1:1 (bacteria to macrophage ratio). Infected macrophages were incubated for 1 h and then washed three times with warm 1 × PBS to remove the unphagocytosed bacteria. Infected macrophages were then either sham-treated or received L-GSH (40 μM) administered at three equal intervals (1 h, 4 d, and 8 d post-infection) throughout the trial. The infected cells were maintained at 37 °C, 5% CO₂ until they were terminated at 1 h and 12 d post-infection to determine the intracellular survival of M. tb.