Mycobacterium -induced TNFα, Bcl-2, Bad and Bak gene expression. THP-1 cells were infected with M. leprae and BCG as described previously and total cellular RNA was extracted, reverse transcribed and PCR was carried out for β-actin, TNFα, Bcl-2, Bad and Bak genes. Gene expression was quantified using scanning densitometry. Panels illustrate gene expression in unstimulated cells 'sp', M. leprae 'ML10', 'ML20', and BCG 'BCG10' and 'BCG20' infected cells at 18 h post-stimulation in a representative experiment. Graphs illustrate expression of TNFα, Bcl-2, Bad and Bak mRNA relative to β-actin in each case.