Fig. 1.
Titan cell signaling in vivo is regulated by the Gpr5 receptor. Mice were infected intranasally with 2 × 107 cells of wild-type KN99a or KN99α or with 2 × 107 cells of the gpr4Δ, gpr5Δ, or gpr4Δ gpr5Δ mating type a or α mutant. At 3 days postinfection, BAL was performed. (A) Small cells (cell body diameter, <10 μm) and titan cells (cell body diameter, >10 μm) were quantified by microscopy. More than 300 cells per treatment per mouse were counted. Error bars indicate standard deviations for 3 to 5 mice per treatment. Statistical analysis of the difference between each mutant strain and the wild-type strain of the same mating type was performed. *, P < 0.02. (B) In vitro cells were grown overnight in rich medium (YPD), fixed in 3.7% formaldehyde, and examined by microscopy. In vivo BAL samples isolated at 3 days postinfection were fixed in 3.7% formaldehyde and were examined by microscopy. Bar, 20 μm.