TABLE 2.

Mean channel fluorescence of CD26 before and after stimulation^a

Cells	Mean channel fluorescence value (SD)
	Day 0 (control)	Day 6
		Control	IL-1α	TNF-α	IFN-γ	PMA	LPS
HGF	5.66 (0.42)	9.29 (0.47)	26.36 (5.35)	15.77 (0.8)	14.67 (0.92)	17.70 (1.71)	12.94 (1.91)
PDL fibroblasts	5.30	5.58	6.33	NDb	9.35	ND	4.07

^aInduction of CD26 on the cell surfaces of HGF and PDL fibroblasts in response to various stimulants is shown. Confluent HGF (donor, YS-G) and PDL fibroblasts (donor, AK) were stimulated with IL-1α (10 ng/ml), TNF-α (40 ng/ml), IFN-γ (200 U/ml), PMA (100 ng/ml), or E. coli LPS (10 μg/ml) for 6 days in α-MEM supplemented with 10% FCS. After being harvested by trypsinization, cells were stained with anti-CD26 MAb and analyzed by fluorescence-activated cell sorting. The results are representative of four different experiments with four different donors (YS-G, NIK, AK-G, and KEK) for HGF and three different experiments with three different donors (AK, TT, and YS) for PDL fibroblasts. Triplicate (HGF) and single (PDL fibroblasts) assays were carried out. 

^bND, not done.