Table III.

Failure of CD34-depleted Monocytes to Exert Accessory Function during Stimulation of T Lymphocytes by LPS

Cell population		DNA synthesis after stimulation with
		None		LPS		PPD
				cpm/culture
Purified T lymphocytes		190 ± 70		210 ± 140		250 ± 180
T plus 10% monocytes		220 ± 20		3,600 ± 320		9,370 ± 1,380
T plus 10% CD34-depleted cells		210 ± 20		350 ± 50		12,300 ± 3,350
T plus 10% CD34-enriched cells		600 ± 290		8,520 ± 90		8,600 ± 380

Purified T lymphocytes (10⁶/ml) or T lymphocytes plus 10% of the accessory cell preparations described above were stimulated with LPS (S. friedenau, 1 μg/ml), or PPD (1 μg/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. The results of one of three experiments are given. Data are expressed as mean ± SD of three independent cultures.