TABLE 1.

TNF-α secretion by dTHP-1 cells and MdM in response to different stimuli and measured by ELISA

Inducera	Concn of TNF-α (pg/ml)b ± SD
	dTHP-1	MdMc
U sup	27.3 ± 6.7	0.3 ± 0.6
E sup	89.7 ± 13.6*	160.5 ± 52.6*
L2 sup	79.8 ± 11.2*	52.3 ± 20.6*
RPMI	35.3 ± 5	-
E. coli LPS (200 ng/ml)	11,167 ± 3,617*	1,012 ± 187*
rhIL-6+rhIL-8	33.9	3.1
rhIL-6+rhIL-8+rhIL-11	37.0	10.2

^aU sup, E sup, and L2 sup represent basal supernatants from HeLa cells either uninfected or infected with C. trachomatis E and L2, respectively, and collected at 48 hpi. No TNF-α was detected in these basal supernatants. The rhIL-6, rhIL-8, and rhIL-11 concentrations in the mixture used to stimulate dTHP-1 and MdM were 45 pg/ml, 150 pg/ml, and 1 ng/ml, respectively.

^bThe TNF-α concentration released from dTHP-1 cells or MdM was determined after 24 h of incubation in the presence of the inducing agent(s). The data shown in this table represent the average values from two or three independent experiments, and the standard deviation was calculated only for the experiments run three times. TNF-α concentrations significantly different (P < 0.05) from the negative control RPMI are indicated by an asterisk. -, Not detected.

^cBecause the number of MdM per well after 10 to 13 days of culture was quite variable, each experiment included replicate wells to ensure that the differences in the TNF-α amounts detected after stimulation were a true reflection of a specific response rather than related to a difference only in the number of cells.