FIG 3.

Macrophage infection indexes and cryptococcal viability. Primary human GM-CSF-derived macrophages (n = 6) (2 × 10⁵ cells/ml), pretreated or not with IFN-γ (50 U/ml), were infected with one of three cryptococcal species (1 × 10⁶ cells/ml). After 3 and 24 h, the lysates of cells diluted 100× in PBS were seeded onto Sabouraud dextrose medium and incubated for 48 to 72 h, and the numbers of CFU were determined. (A) Primary GM-CSF-derived macrophages (2 × 10⁵ cells/ml) were infected with cryptococcal species (1 × 10⁶ cells/ml) on coverslips under the conditions described above. After the incubation time, cells were stained, and the percentage of infected macrophages, number of intracellular cryptococci per macrophage, and infection index were determined. (B to D) C. neoformans sensu stricto (B), C. bacillisporus (C), and C. gattii sensu stricto (D) internalized by macrophages. (E) Total numbers of live cryptococcal cells recovered from macrophages after 3 and 24 h of incubation. N, macrophage nucleus; Y, yeast cell. *, P ≤ 0.05.