Evaluation of Humoral Immunity to Mycobacterium tuberculosis-Specific Antigens for Correlation with Clinical Status and Effective Vaccine Development

Table 2

Serum IgG responses to seven mycobacterial antigens.

Group	Optical density at 450 nm (mean ± SD) and positive rate (%)
	ESAT-6	CFP-10	MDP1	Ag85A	Acr	HBHA	HrpA
Cut-off values	0.067	0.077	0.118	0.037	0.129	0.140	0.072
Negative control	0.068 ± 0.155; 36.4%	0.084 ± 0.160; 41.9%	0.103 ± 0.108; 36.5%	0.037 ± 0.074; 44.6%	0.143 ± 0.213; 32.4%	0.091 ± 0.157; 23.0%	0.050 ± 0.210; 16.2%
Active disease	0.248 ± 0.590^a; 55.7%	0.252 ± 0.508^a; 58.0%	0.157 ± 0.240; 48.9%	0.068 ± 0.246; 51.1%	0.487 ± 0.714^b; 76.1%	0.351 ± 0.502^b; 59.3%	0.256 ± 0.276^b; 77.3%
Past disease	0.068 ± 0.129^c; 39.3%	0.230 ± 0.345; 64.3%	0.207 ± 0.259^d; 54.8%	0.080 ± 0.136; 56.0%	0.277 ± 0.381^c; 66.7%	0.300 ± 0.436^d; 58.3%	0.290 ± 0.264^e; 79.8%
Latent TB infection	0.079 ± 0.100; 41.2%	0.195 ± 0.190; 76.5%	0.257 ± 0.320; 52.9%	0.040 ± 0.115; 41.2%	0.210 ± 0.292; 64.7%	0.277 ± 0.334; 64.7%	0.325 ± 0.368^f; 82.4%
AUROC	0.63	0.59	0.52	0.51	0.74	0.74	0.82

(active versus control), ^b (active versus control), ^c (active versus past), ^d (past versus control), ^e (past versus control), ^f (latent versus control).
Optimal cut-off values were chosen when the Youden’s index (sensitivity and specificity − 1) was maximal.
AUROC: areas under the receiver operating characteristic curve.