FIG. 2.

Numbers of nonlymphoid cells expressing CD11b and MHC class II in the alveolar spaces of Pneumocystis-infected neonates were significantly lower than those in adult lungs through 2 weeks postinfection. Mice were infected with Pneumocystis as neonates (24 to 72 h after birth) or adults. Control mice received HBSS vehicle. Lungs were lavaged at the indicated time points, cells were stained with antibodies specific for CD11b and MHC class II, and cells were examined by using flow cytometry. Cells were gated on large nonlymphocytes, and the numbers of cells expressing (A) CD11b and (B) MHC class II were counted. Data represent the means ± SD for three to five mice per group. *, P < 0.05 compared to all other groups at the same time point.