Infectious particle identity determines dissemination and disease outcome for the inhaled human fungal pathogen Cryptococcus
Fig 5
Spore phagocytosis and lymph node dissemination are dependent on intrinsic spore properties.
(A) Phagocytosis of formaldehyde-fixed spores by RAW 264.7 macrophages at various points in germination (germination progression indicated by increasingly darker shading). Data are representative of multiple, independent (3) biological replicates. (B) Phagocytosis of spores and/or yeast expressing GFP or mCherry (incubated individually or together) by RAW 264.7 macrophages in vitro. Results are illustrated as stacked bar graphs showing the mean±SEM percent of macrophages containing mCherry-positive fungal cells (red), GFP-positive fungal cells (green) or both (black) (n = 3) after 4 hours of co-incubation. Compositions of the populations incubated with macrophages are represented below the plots (G = GFP, m = mCherry). (C) Fungal burden quantity and composition in the lungs 3 days post-infection in mice infected with 5x106 mCherry-spores, 5x106 GFP-yeast, mCherry-yeast and GFP-yeast (5x106 of each), or mCherry-spores and GFP-yeast (5x106 of each). The results are expressed in jitter plots of pie-charts with the position of each pie chart indicating the fungal burden identified in a single mouse (y-axis). The contents of each pie-graph indicate the composition of the fungal burden in that same mouse (in 50 randomly-selected isolates per mouse). A horizontal line identifies the mean fungal burden of each group, and the mean composition of the fungi of all mice per group is represented by pie-graphs along the x-axis (n = 5–8). Compositions of the initial inocula are represented below the plot (G = GFP, m = mCherry). (D) Fungal burden quantity and composition in the lymph nodes (L.N.) 3 days post-infection in mice infected with mCherry-spores, GFP-yeast, mCherry-yeast and GFP-yeast, or mCherry-spores and GFP-yeast. Data are from lymph nodes from the same mice shown in (C) and are represented in the same manner. Empty pie charts represent mice in which no fungal colonies were recovered from the lymph nodes. For the difference in the ratios of mCherry+:GFP+ colonies in lung vs. lymph node p = 1.73x10-8 (by a Student's t-test).