Figure 1. The Δsld8 strain does not show a growth defect at acidic or neutral pH, but is completely avirulent.

The mutant and wildtype strains were examined for their growth profile in DMEM at A) pH=4.0 and B) pH=7.4 at 37 °C in the presence of 5% CO₂. Growth was assayed by drawing 100 μL aliquots, serial dilution, and plating on YPD agar to enumerate CFU (three independent experiments were performed for each growth condition). C) Four weeks old immunocompetent CBA/J mice were infected with wild-type, Δsld8, and Δsld8+SLD8 mutant strains and monitored for survival (10 were used per strain). Mice infected with the wild-type and reconstituted strain succumbed to the infection in an average of 25.5 and 31.5 days, respectively. Mice infected with the Δsld8 strain remained alive for the duration of the experiment (90 days post infection, p value=0.0001). Fungal burden was quantified in D) the lungs and E) the brain of five mice per condition. The fungal burden values were statistically significantly different compared to the wild-type (shown by *) or the reconstituted strain (shown by $). A p-value of 0.05 was used for all analysis.