FIG. 5.

Host response is modified in the absence of ALL1. (a and b) Hematoxylin- and eosin-stained and mucicarmine-stained lung tissue of SM variant-infected (a) and all1Δ mutant-infected (b) mice on day 10 after the mice were given 10⁶ cells i.t. Note the beginning of granuloma formation in the SM variant-infected mouse (a) and the extracellular accumulation of yeast cells in the alveolar spaces of the all1Δ mutant-infected mouse (b). At day 46 hematoxylin and eosin staining of lung tissue revealed an excessive but ineffective host response in the all1Δ mutant-infected mice (d), whereas the SM variant-infected mice (c) successfully cleared the infection. (e and f) Immunohistochemistry with a macrophage-specific MAb, MAC3, revealed significantly more macrophages in all1Δ mutant-infected lungs (f) than in SM variant-infected lungs (e). (g) The inflammatory response in an SM variant-infected mouse whose strain switched to a MC phenotype is similar to the inflammatory response in all1Δ mutant-infected mice. (h) Accumulation of yeast cells in the subarachnoid space in an all1Δ mutant-infected rat.