Figure 1.

Biofilm-like cryptococcomas (brain lesions) in hippocampal tissue sections 14 days after intratracheal inoculation of C. neoformans strain H99 in a C57BL/6J mouse. (A) Confocal microscopy of the hippocampus in the brain of an infected animal with cap59 (acapsular mutant). Capsule deficient mutants are cleared by phagocytic cells in the lungs of infected animals and are unable to reach the central nervous system; (B) Immunofluorescent image of a hippocampal tissue section of a mouse infected with wild-type C. neoformans H99 displaying large cryptococcomas (yellow arrows) filled with yeasts cells and abundant amounts of capsular polysaccharide released (white arrow heads) in the area; (C,D) Cryptococcomas are characterized by significant neuronal loss due to biofilm-like colonization of brain tissue; (E,F) High magnification images show a substantial number of yeast cells attached to neuronal tissue. For panels A–F, capsular-specific monoclonal antibody 18B7 (monoclonal antibody 18B7; green) was used to label fungal cells and capsular polysaccharide released. GFAP (red) and DAPI (blue) staining were used to label the cell bodies and nuclei of astrocytes, respectively. Scale bars: A,B = 230 µm; C = 87 µm; D = 35 µm; E = 21 µm; F = 17 µm.