Table I.
Comparison of biologic and toxic activity of mCTs
| Nasal Adjuvant | cAMP Inductiona (pmol/mg protein) | Y1-Cell Assayb (pg/ml) | Heal Loop Testc (W:L ratio) |
|---|---|---|---|
| nCT | 104.4 ± 2.3†† | 0.06 ± 0.01†† (1)d | 164.3 ± 4.0†† |
| E112K/KDEV | 5.3 ± 0.3** | 125.0 ± 20.8** (1/2083) | 47.7 ± 9.7** |
| E112K/KDGL | 6.5 ± 0.2** | 166.7 ± 9.7** (1/2778) | 41.7 ± 3.4** |
| E112K | 7.0 ± 1.0** | 234.1 ± 44.3* (1/3902) | 45.5 ± 0.4** |
| PBS | 7.4 ± 0.5** | 37.6 ± 4.4** |
CHO cells (1.5 × 104 cells/well) were cultured in F-10 medium containing 1 % FCS with 100 ng/ml of each toxin for 18 h, and the cAMP induction was assessed using an enzyme immunoassay. Values represent the mean ± SEM of nine culture wells in each group. **, p < 0.01, when compared with nCT. ††, p < 0.01, when compared with mCT E112K.
Y-1 cells were cultured with F-12 medium containing 15% horse serum and 2.5% FCS and serial dilution of each toxin for 24 h. The enterotoxin concentration required to initiate rounding was determined. Values represent the mean ± SEM of of 12 culture wells in each group. *, p < 0.05; **, p < 0.01, compared with nCT. ††, p < 0.01, when compared with mCT E112K.
The ratio of the weight in milligrams to length in centimeters (W:L ratio) after injection of dmCTs into the loop. Each loop was injected with 0.1 ml of 1 /xg of dmCTs or nCT. The weight and length of each loop were measured after 3 h values. Values represent the mean ± SEM of six loops in each group. **, p < 0.01, when compared with nCT. ††, p < 0.01, when compared with mCT E112K.
The values in parenthesis is the ratio of the toxicity of dmCTs to the toxicity of nCT.