TABLE 2.
The effect of directed Spa47 mutations on Shigella hemolysis and invasion
| S. flexneri strain | Complementation | Relative invasion (% ± S.D.)a | Relative hemolysis (% ± S.D.)b |
|---|---|---|---|
| 2457T (WT) | None | 100 | 100 |
| spa47 null | None | 0.8 ± 1.1 | 0.9 ± 2.0 |
| spa47 null | spa47/pWPsf4 | 81.7 ± 10.8 | 81.4 ± 11.6 |
| spa47 null | spa47 K165A/pWPsf4 | 0.5 ± 0.2 | 1.1 ± 1.9 |
| spa47 null | spa47 E188A/pWPsf4 | 0.2 ± 0.2 | 0.9 ± 2.0 |
| spa47 null | spa47 R350A/pWPsf4 | 0.1 ± 0.2 | 1.2 ± 2.5 |
| spa47 null | spa47Δ1–79/pWPsf4 | 0.2 ± 0.1 | 0.9 ± 2.2 |
a The ability of the Shigella mutants to invade cultured host cells was measured by a standard gentamicin protection assay (see “Experimental Procedures”). Invasion results are presented as the percentage of invasion by the wild-type S. flexneri strain 2457T.
b The ability of each Spa47 Shigella mutant to lyse red blood cells was tested using a hemolysis assay that quantifies released hemoglobin following incubation of erythrocytes with the described Shigella mutants. Hemolysis results are presented as the percentages of hemoglobin released by the wild-type S. flexneri strain (2457T). The experiments were all repeated in triplicate, and results represent the means ± standard deviation.