Table 1

Experimental design of the antitoxin NAb assay DOE

Run orderAnalystDayBlockCell density (no. of cells/well)Toxin concnaPreincubation time (h)
11111,000High2
2111500High0.5
31111,000Low0.5
4111500Low2
5111750Medium1
6111750Medium1
7212500High2
8212500Low0.5
92121,000Low2
102121,000High0.5
11212750Medium1
12212750Medium1
13123750Low1
14123500Medium1
151231,000Medium1
16123750Medium1
17123750Medium1
18224750Medium0.5
19224750High1
20224750Medium2
21224750Medium1
22224750Medium1
  • a For the anti-TcdA NAb assay, low, medium, and high toxin concentrations were 3, 4, and 5 ng/ml, respectively. For the anti-TcdB NAb assay, low, medium, and high toxin concentrations were 20, 40, and 80 pg/ml, respectively.