Table 3.

Metal sensitivity profile of L. major lines in the presence of BSO^a

Compound	Mean EC50 (μM) ± SD [EC50 decrease]b
	pXG	ABCI4	ABCI4K/M
Sb(III)	20.87 ± 1.80	53.74 ± 3.35	21.16 ± 3.60
Sb(III) + BSOc	9.28 ± 0.48 [2.2]*	15.30 ± 1.23 [3.6]*	11.48 ± 0.96 [1.9]*
Cd(II)	42.36 ± 4.12	82.55 ± 8.84	40.96 ± 2.30
Cd(II) + BSO	6.30 ± 0.23 [6.7]*	6.85 ± 0.45 [13.7]*	6.36 ± 0.37 [6.4]*

^aParasites were grown as described in Materials and Methods for 72 h at 28°C in the presence of increasing concentrations of drugs. Cell viability was determined by using an MTT-based assay. Data are means from three independent experiments. Significant differences were determined by the Student t test (*, P < 0.01).

^bThe EC₅₀ decrease, indicated between brackets, was calculated by dividing the EC₅₀s after metal treatment by that for metal plus BSO in each Leishmania line.

^c3 mM BSO (a γ-glutamylcysteine synthetase inhibitor) was added to the culture medium 48 h before the sensitivity experiment.