FIG. 2.

sxi1αΔ strains are as virulent as wild-type strains in vivo. (A) Wild-type, sxi1αΔ, and control strains in the serotype A background were inoculated into A/Jcr mice intranasally. Mice were monitored for the development of symptoms consistent with cryptococcal meningitis, and moribund animals were sacrificed. The median survival time of mice infected with the wild-type strain was 21.5 days compared to 22.3 and 23.0 days for the independent sxi1αΔ test strains and 24.0 days for the ectopic control strain. P values from a Mann-Whitney test of statistical significance comparing each test strain with the wild-type control were >0.05, confirming that there were no significant differences among the strains tested. (B) Wild-type and sxi1αΔ strains in the serotype D background were inoculated into DBA mice by tail vein injection. Mice were monitored for the development of symptoms consistent with cryptococcal meningitis, and moribund animals were sacrificed. The median survival time of mice infected with the wild-type strain was 39.5 days compared to 32.4 and 28.0 days for the independent sxi1αΔ test strains. P values from a Mann-Whitney test of statistical significance comparing each test strain with the wild-type control were >0.05, indicating that there were no significant differences among the strains tested.