FIG 4.

Enhanced phagocytosis in uninfected and infected Lyz2-DP1^−/− mice. (a) Splenic phagocytic function was assessed by administering Dil-labeled liposomes or PBS to uninfected mice and assessing uptake in the spleen 20 h after administration. CD45⁺ CD11b⁺ cells were gated and assayed for liposome-dye uptake. (b) Summary data showing the frequency of positive cells. Data are represented as means ± SEM from three independent experiments with 6 to 7 mice per group. (c) Cells were isolated from the CNS of infected WT and Lyz2-DP1^−/− mice and exposed to pHrhodo E. coli beads as described in Materials and Methods. FMO (fluorescence minus one) was used to set gates. After 1 h of incubation, CD45^hi CD11b⁺ cells were assessed for rhodamine expression by flow cytometry. (d) Representative summary data from two experiments (means ± SEM). (e) Infected brains were harvested and analyzed for Iba1 and N protein expression. The confocal image shows increased numbers of doubly labeled cells, suggestive of enhanced phagocytosis of infected cells. The arrows show double-positive cells. The image is representative of results from an experiment performed with three mice per group. (f) Summary data. Five random fields from each of three mice were analyzed, and the number of double-positive cells was recorded. *, P < 0.05; **, P < 0.01. Bar, 50 μm.