TABLE 3.
ELISA OD values obtained with anti-CT and anti-STa antisera to verify the expression of each STa-toxoid-dmLT fusion protein
| Fusion proteina | Mean OD ± SD |
|---|---|
| Anti-CTb | |
| STa | 1.05 ± 0.03 |
| 3F | 1.4 ± 0.02 |
| 8Q | 1.32 ± 0.0 |
| 9A | 1.5 ± 0.03 |
| 12I | 1.5 ± 0.07 |
| 12S | 1.4 ± 0.03 |
| 12T | 1.36 ± 0.03 |
| 13A | 1.41 ± 0.01 |
| 13F | 1.49 ± 0.07 |
| 14H | 1.34 ± 0.03 |
| 14Q | 1.28 ± 0.02 |
| 14T | 1.32 ± 0.04 |
| 14V | 1.45 ± 0.07 |
| 16K | 1.36 ± 0.06 |
| 16M | 1.29 ± 0.02 |
| (–) | 0.11 ± 0.05 |
| Anti-STac | |
| STa | 1.95 ± 0.07 |
| 3F | 1.94 ± 0.02 |
| 8Q | 1.69 ± 0.0 |
| 9A | 1.97 ± 0.03 |
| 12I | 1.84 ± 0.05 |
| 12S | 1.95 ± 0.04 |
| 12T | 1.71 ± 0.0 |
| 13A | 1.86 ± 0.05 |
| 13F | 1.71 ± 0.06 |
| 14H | 1.93 ± 0.07 |
| 14Q | 1.89 ± 0.03 |
| 14T | 1.91 ± 0.05 |
| 14V | 1.89 ± 0.02 |
| 16K | 2.1 ± 0.01 |
| 16M | 2.04 ± 0.01 |
| (–) | 0.34 ± 0.11 |
Fusion proteins: STa, fusion 3×STa-dmLT; 3F, 3×STaS3F-dmLT; 8Q, 3×STaE8Q-dmLT; 9A, 3×STaL9A-dmLT; 12I, 3×STaN12I-dmLT; 12S, 3×STaN12S-dmLT; 12T, 3×STaN12T-dmLT; 13A, 3×STaP13A-dmLT; 13F, 3×STaP13F-dmLT; 14H, 3×STaA14H-dmLT; 14Q, 3×STaA14Q-dmLT; 14T, 3×STaA14T-dmLT; 14V, 3×STaA14V-dmLT; 16K, 3×STaT16K-dmLT; 16M, 3×STaT16 M-dmLT. Each purified fusion protein (100 ng per well) was used to coat ELISA 2HB plate (in triplicate). PBS was used as the negative control (–).
Rabbit anti-CT (1:3,000; Sigma) and HRP-conjugated goat-anti-rabbit IgG (1:3,000; Sigma) were used as the primary and secondary antibodies to detect the LT peptide of each fusion.
Protein A-purified rabbit anti-STa serum (1:3,000; Robertson laboratory) and HRP-conjugated goat anti-rabbit IgG (1:3,000) were used to detect the STa toxoid of each fusion protein.