TABLE 3.
Correlation between results of in vitro assays of sera from mice challenged with Y. pestis strain C12a
Vaccine | Challenge dose | Correlation variable (assay)c | Correlation (P)b
|
||||
---|---|---|---|---|---|---|---|
% Livec
|
Caspase | Anti-F1 titer | Anti-V titer | ||||
FACS | Micro | ||||||
F1+V | All | Anti-V titer | 0.005 | NS | 0.007 | 0.010 | - |
Anti-F1 titer | NS | NS | NS | - | 0.010 | ||
Caspase | 0.0004 | <0.0001 | - | NS | 0.007 | ||
% Live (FACS) | - | <0.0001 | <0.0001 | NS | 0.005 | ||
% Live (Micro) | <0.0001 | - | <0.0001 | NS | NS | ||
F1-V | All | Anti-V titer | NS | 0.048 | 0.043 | NS | - |
Anti-F1 titer | 0.015 | 0.028 | NS | - | NS | ||
Caspase | 0.0002 | <0.0001 | - | NS | 0.043 | ||
% Live (FACS) | - | <0.0001 | 0.0002 | 0.015 | NS | ||
% Live (Micro) | <0.0001 | - | <0.0001 | 0.028 | 0.048 | ||
V | All | Anti-V titer | NS | NS | NS | NS | - |
Anti-F1 titer | NS | NS | NS | - | NS | ||
Caspase | <0.0001 | <0.0001 | - | NS | NS | ||
% Live (FACS) | - | <0.0001 | <0.0001 | NS | NS | ||
% Live (Micro) | <0.0001 | - | <0.0001 | NS | NS | ||
All (combined) | 107 | Anti-V titer | NS | NS | NS | 0.004 | - |
Anti-F1 titer | NS | NS | NS | - | 0.004 | ||
Caspase | 0.0002 | 0.0002 | - | NS | NS | ||
% Live (FACS) | - | <0.0001 | 0.0002 | NS | NS | ||
% Live (Micro) | <0.0001 | - | 0.0002 | NS | NS | ||
All | 108 | Anti-V titer | 0.0137 | NS | NS | NS | - |
Anti-F1 titer | NS | NS | NS | - | NS | ||
Caspase | <0.0001 | <0.0001 | - | NS | NS | ||
% Live (FACS) | - | <0.0001 | <0.0001 | NS | 0.014 | ||
% Live (Micro) | <0.0001 | - | <0.0001 | NS | NS | ||
All | 109 | Anti-V titer | 0.001 | 0.0031 | 0.0040 | 0.001 | - |
Anti-F1 titer | 0.002 | NS | 0.0050 | - | 0.001 | ||
Caspase | 0.001 | <0.0001 | - | 0.005 | 0.004 | ||
% Live (FACS) | - | <0.0001 | 0.001 | 0.002 | 0.001 | ||
% Live (Micro) | <0.0001 | - | <0.0001 | NS | 0.003 | ||
All | All (combined) | Anti-V titer | 0.0002 | 0.006 | 0.0004 | 0.0012 | - |
Anti-F1 titer | 0.003 | 0.012 | NS | - | 0.001 | ||
Caspase | <0.0001 | <0.0001 | - | NS | 0.0004 | ||
% Live (FACS) | - | <0.0001 | <0.0001 | 0.003 | 0.0002 | ||
% Live (Micro) | <0.0001 | - | <0.0001 | 0.012 | 0.006 |
Sera tested were collected prechallenge from a total of 124 mice vaccinated twice with one of three vaccines (V alone, F1-V fusion, or F1+V). The mice were challenged s.c. with Y. pestis C12 (107, 108, or 109 LD50s).
Correlations were determined to be significant (P < 0.05) or not significant (NS; P > 0.05) by Pearson product-modified correlation analysis. -, the correlation was not determined or was not applicable.
Micro, microscopy. FACS-based and microscopy staining assays were used to determine L/D viability, and the percentages of live cells observed were used for correlation analyses.