Table 2. Host triacylglycerol-derived fatty acids imported by Mtb are incorporated intact into Mtb triacylglycerol.

Oleic acid [9,10-3H, 1-14C] Double Isotope Labeling Experiment
	3H: 14C DPM Ratios	Radioactivity as Percent of Total Lipids
		3H	14C
THPM TAG	0.47±0.01	32±6	51±8
Mtb TAG	0.56±0.01	5±1	6±0

Double isotope labeled oleic acid [9,10-³H, 1-¹⁴C] was used for metabolically labeling THPM for 24 h under 1% O₂. After infection of THPM at an MOI of 5.0 for 3 days, Mtb were recovered and contaminating host TAG removed prior to lipid extraction. TAG was purified from the respective total lipid extracts by silica-TLC and the ratios of ³H and ¹⁴C radioactivities (dpm) were determined as described in Methods. The radioactivities in TAG are expressed as percentages of the radioactivities in the respective total lipid extracts. Data from a typical experiment are shown as average and standard deviation values calculated from triplicate samples.