Table 6. Suppression of T-cell proliferation by CSCs but not by their paired FBS tumor cells.

Patient	Mitogen	Tumor cells	% Divided cells*	Division index†	Proliferation index‡
080125	No	No	14	0.2	1
	PHA/ConA	No	44	1	2
	PHA/ConA	CSCs	27	0.3	1
	PHA/ConA	FBS tumor cells	46	1	2
	OKT3	No	57	1.5	3
080418	No	No	12	0.1	1
	PHA/ConA	No	54	1	2
	PHA/ConA	CSCs	30	0.4	1
	PHA/ConA	FBS tumor cells	46	1	2
	OKT3	No	57	1.5	3

NOTE: PBMCs (1 × 10⁷) of healthy donor were stained with 1 mmol/L CSFE and stimulated with PHA/concanavalin A in the presence or not of 5-d cultured CSCs or FBS tumor cell lines isolated from 080125 or 080418 GBM patients. After 5 d of incubation, cells were harvested and the CFSE profile was assessed by flow cytometry. The experiment was repeated twice for each time point (72 and 120 h) and data were consistent throughout the experiments with an SD of ≥ 1.4 ≤ 2.3 for each value. Statistical analysis of differences between means of the % divided cells, of the division index, or of the proliferation index was done by two-tailed t test. Data are referred to CD3⁺-gated cells.

Abbreviation: ConA, concanavalin A.

^*% Divided cells, the percentage of cells of the original sample that divided.

^†Division index, the average number of divisions that a cell has undergone.

^‡Proliferation index, the average number of divisions that the divided cells underwent.