Table II.

CD34⁺ Blood Stem Cells Restore Activation of T Lymphocytes from LPS Nonresponders by LPS

Cell population		DNA synthesis after stimulation with
		None		LPS		Recall antigen
				cpm/culture
Experiment 1
PBMCs		680 ± 260		520 ± 90		12,080 ± 1,580
CD34-depleted PBMCs		70 ± 10		80 ± 10		20,370 ± 2,680
CD34-depleted PBMCs plus CD34-enriched cells		590 ± 130		8,380 ± 110		14,500 ± 90
Experiment 2
PBMCs		550 ± 290		420 ± 10		32,170 ± 5,880
CD34-depleted PBMCs		160 ± 100		600 ± 170		32,640 ± 3,950
CD34-depleted PBMCs plus CD34-enriched cells		160 ± 40		2,230 ± 540		31,700 ± 2,640
Experiment 3
PBMCs		140 ± 50		250 ± 80		2,110 ± 910
CD34-depleted PBMCs		350 ± 40		390 ± 60		2,490 ± 120
CD34-depleted PBMCs plus CD34-enriched cells		770 ± 240		12,010 ± 1,200		3,370 ± 1,030

Cells (10⁶/ml) plus 10% accessory cells were stimulated with LPS (S. friedenau, 1 μg/ml), TT (donor 1, 1 Lf/ml), PPD (donor 2, 1 μg/ml), or BCG (donor 3, 4,000 CFU/ml) and cultured for 7 d in RPMI 1640 plus 10% HS in a final volume of 200 μl/culture. For the last 8 h of culture, cells were pulsed with [³H]TdR (0.2 μCi/culture), then harvested on glass filter mats, and the radioactivity was measured in a β-counter. Data are expressed as mean ± SD of three independent cultures.