Figure 1Comparison of the results of lethal challenge and in vivo toxin neutralization assays for diphtheria toxoid. (A) When the potency of diphtheria toxoid was calculated through lethal challenge assay, all 15 vaccine lots had appropriate potencies satisfying the limits for adult vaccines of 2 IU/0.5 mL. (B) The results of in vivo toxin neutralization assay showed potencies exceeding 1 unit/mL for all vaccine lots.
Figure 2Comparison of the results of lethal challenge and in vivo toxin neutralization assays for tetanus toxoid. (A) When the potency of tetanus toxoid was calculated through lethal challenge assay, all 15 vaccine lots had appropriate potencies satisfying the limits for adult vaccines of 20 IU/0.5 mL. (B) The results of in vivo toxin neutralization assay showed potencies exceeding 8 units/mL for all vaccine lots.
Table 1Results of potency estimation of diphtheria and tetanus toxoid by lethal challenge and in vivo toxin neutralization assays.
Vaccine number |
Potency |
Diphtheria toxoid |
Tetanus toxoid |
Lethal challenge assay (IU/0.5 mL) |
In vivo toxin neutralization assay (units/mL) |
Lethal challenge assay (IU/0.5 mL) |
In vivo toxin neutralization assay (units/mL) |
MC11 |
15.4 |
> 2 |
63.4 |
> 16 |
MC12 |
14.6 |
> 2 |
64.4 |
> 16 |
MC13 |
14.8 |
> 2 |
68.1 |
> 16 |
MC14 |
13.1 |
> 2 |
44.7 |
> 16 |
MC15 |
15.7 |
> 2 |
46.2 |
> 16 |
MC16 |
13.8 |
> 2 |
44.7 |
> 16 |
MC21 |
8.3 |
1 |
44.3 |
8 |
MC22 |
10.2 |
1 |
66.9 |
8 |
MC23 |
9.2 |
> 2 |
55.9 |
8 |
MC24 |
7.6 |
1 |
51.3 |
8 |
MS21 |
8.0 |
1 |
57.5 |
8 |
MS22 |
9.7 |
> 2 |
62.7 |
8 |
MS23 |
10.8 |
> 2 |
59.6 |
8 |
MP21 |
6.3 |
1 |
61.8 |
8 |
MP22 |
11.4 |
1 |
79.1 |
8 |