Table 4.
Serum bactericidal activities of sera collected on day 63
| Serum bactericidal titera for strain: | |||
|---|---|---|---|
| Immunization group | |||
| FA19 | MS11 | FA1090 | |
| NB-Ctb (IN/IP) | 200 (74% ± 9.2) | 400 (79% ± 1.4) | >25b |
| NB-L2-Ctb (IN/IP) | 200 (62% ± 0.7) | 400 (66% ± 21.2) | 50 (60% ± 10.6) |
| NB-L2-Ctb (s.c./IP) | 200 (80% ± 8.5) | 400 (58% ± 9.9) | 100 (70% ± 3.5) |
a
Titers were calculated as the reciprocal of the dilution that gave >50% killing compared to the sham-immunized control sera. The average percent killing determined from duplicate assays ± standard deviation is shown in parentheses.
b
Less than 50% killing was achieved at a dilution of 1/25. Lower dilution factors were not tested.