FIG. 4.

Mouse infection with H. capsulatum. (A) Mice infected with 10⁶ yeast cells of strain G217B died within 40 days after infection, whereas all mice infected with strain HcD3 survived. (B) About 10⁷ G217B yeast cells killed all mice after 23 days, whereas all mice infected with 10⁷ HcD3 yeast cells survived up to 30 days after infection. (C) All mice infected with 5 × 10⁷ G217B yeast cells died within 6 days, while 7 out of 10 mice infected with the same inoculum of HcD3 survived up to 45 days after infection. (D) Surviving mice were challenged with a lethal dose (5 × 10⁷ yeast cells) of the virulent strain G217B. After 20 days (60 days from the initial infection with attenuated HcD3 strain) six mice still survived.