TABLE 2.
Statistical comparison of median survival timesa
| Type 4 challenge immunization |
P value for comparison with the following type 2 challenge immunization
|
|||||||
|---|---|---|---|---|---|---|---|---|
| Alum | PdB | PsaA | PspA | PdB-PsaA | PdB-PspA | PsaA-PspA | PdB-PsaA-PspA | |
| Alum | NSb | NS | NS | <0.05 | =0.001 | <0.025 | <0.001 | |
| PdB | <<0.001 | NS | NS | NS | =0.01 | NS | <0.01 | |
| PsaA | <<0.01 | <0.05 | NS | NS | <0.025 | NS | <0.01 | |
| PspA | NS | <<0.001 | <<0.001 | NS | <0.01 | NS | <0.01 | |
| PdB-PsaA | NS | <<0.001 | <0.025 | <0.025 | <0.01 | NS | <0.01 | |
| PdB-PspA | <<0.001 | <0.01 | <0.001 | <<0.001 | <<0.001 | NS | NS | |
| PsaA-PspA | NS | <<0.001 | <0.001 | NS | NS | <<0.001 | <0.05 | |
| PdB-PsaA-PspA | <<0.001 | NS | <<0.01 | <<0.001 | <<0.001 | NS | <<0.001 | |
a
Groups of immunized mice were challenged either by a capsular type 2 strain (D39) or by a capsular type 4 strain (WCH43). Differences were analyzed using the Mann-Whitney U test (one tailed).
b
NS, not significant (P ≥ 0.05).