TABLE 4.
Shigella antigen-specific serum IgA immune responses
| Shigella serotype | LPS multiplier | Antigen-specific serum IgA responses a | |||
|---|---|---|---|---|---|
| LPS b | InvaplexNAT | IpaB | IpaC | ||
| S. flexneri 2a | 1× | 57 ± 55 17% |
641 ± 394*** 100% |
1,018 ± 909*** 100% |
720 ± 492**** 100% |
| 2× | 90 ± 125 33% |
286 ± 519* 66% |
360 ± 487* 83% |
404 ± 483*** 100% |
|
| 4× | 160 ± 157*
c
50% |
509 ± 1,021*** 83% |
321 ± 522* 66% |
1,283 ± 1,060**** 100% |
|
| 8× | 80 ± 123 17% |
571 ± 1,008*** 100% |
360 ± 279* 83% |
1,814 ± 1,845**** 100% |
|
| Placebo | 45 ± 0 0% |
51 ± 18 0% |
51 ± 18 0% |
57 ± 55 17% |
|
| S. flexneri 3a | 1× | 71 ± 23 0% |
227 ± 231*** 83% |
641 ± 982**** 100% |
1,283 ± 789**** 100% |
| 2× | 71 ± 23 0% |
160 ± 133** 67% |
404 ± 625*** 83% |
1,143 ± 864*** 100% |
|
| 4× | 127 ± 148* 50% |
286 ± 216*** 83% |
286 ± 216** 83% |
1,440 ± 984**** 100% |
|
| 8× | 101 ± 55 33% |
202 ± 110** 83% |
90 ± 44 17% |
1,283 ± 1,060**** 100% |
|
| Placebo | 45 ± 0 0% |
45 ± 0 0% |
51 ± 18 0% |
160 ± 246 50% |
|
| S. flexneri 6 | 1× | 74 ± 64 29% |
121 ± 511 43% |
1,590 ± 1,785**** 100% |
878 ± 8,491**** 100% |
| 2× | 61 ± 24 0% |
199 ± 230* 71% |
1,304 ± 733**** 100% |
360 ± 226*** 100% |
|
| 4× | 67 ± 24 0% |
219 ± 505* 71% |
591 ± 514**** 100% |
439 ± 428*** 100% |
|
| 8× | 199 ± 102**** 86% |
163 ± 236 57% |
360 ± 1,032*** 71% |
720 ± 451**** 100% |
|
| Placebo | 45 ± 0 0% |
45 ± 0 0% |
50 ± 17 0% |
50 ± 17 0% |
|
| S. sonnei | 1× | 127 ± 109* 33% |
360 ± 478**** 100% |
321 ± 197**** 100% |
1,616 ± 4,247**** 100% |
| 2× | 143 ± 141* 50% |
509 ± 452**** 100% |
321 ± 265**** 100% |
1,440 ± 2,007**** 100% |
|
| 4× | 127 ± 49* 50% |
255 ± 226*** 83% |
101 ± 68 50% |
720 ± 957** 100% |
|
| 8× | 113 ± 120 50% |
286 ± 210*** 100% |
64 ± 54 17% |
1,018 ± 872*** 100% |
|
| Placebo | 45 ± 0 0% |
45 ± 0 0% |
45 ± 0 0% |
113 ± 46 33% |
|
a
Responses are shown as geometric mean endpoint titers ± standard deviation with percent responders (defined as a ≥4-fold-increase over baseline).
b
LPS responses are directed to the homologous serotype used for vaccination.
c
Significance determined by one-way ANOVA with Bonferroni post hoc test compared to placebo group *P < 0.05, **P ≤ 0.01, ***P ≤ 0.001, ****P ≤ 0.0001.