To avoid any difference in cell wall composition that may exist between divergent Mtb mutant strains that are missing the RD1 locus, which encodes the ESX1 system, we instead chose to take an infection stock of mCherry Mtb prepared in the absence of Tween 80, split it in half, and heat killed one aliquot at 85°C for 10 min. The gene discussed is ESX1; the disease is infection.