ESAT-6 downregulated LPS-induced ERK kinase activity. (A) and (B) represent the autoradiogram of the ERK kinase assay using Myelin basic protein (MBP) as a substrate in cytoplasm and nucleus respectively. Lane.1. Unstimulated cells, Lane.2. Cells stimulated with 5 μg/ml ESAT-6, Lane.3. Cells stimulated with 0.1 μg/ml of LPS, Lane.4. Cells stimulated with LPS and ESAT-6, Lane.5. Cells stimulated with 1 mM Na3VO4 and 5 μg/ml ESAT-6, Lane.6. Cells stimulated with 1 mM Na3VO4. (C) and (D) represents the graph showing fold change of the densitometric values obtained from the densitometric studies of the autoradiogram of (A) and (B) respectively. Unstimulated cells were given a value 1.00. The data represented as mean +/- S.D. of three independent experiments.