Figure 3.

Representative splenic pathology. Mice injected intravenously as in Table 1 after treatment with either isotype control or neutrophil depleting antibodies (anti-Gr1) as indicated. The spleen was harvested 2–10 days after exposure. A representative image of normal (R mucosa exposed), mild pathology (Coagulase negative Staphylococcus; CNS exposed), or severe pathology (P. aeruginosa infected neutropenic mice) is shown (see Table 1). Mild pathology for Gram-negative exposures was marked by alteration of follicular definition with expansion of B-cell zone (hyperplasia). For neutropenic mice injected with CNS, within the “red pulp” (RP; vascular spaces) and adjacent to the “white pulp” (WP; lymphoid tissue) there were dense focal and coalescing clusters of histiocytic cells (asterisk); these changes can be seen throughout the entire splenic section. Severe pathology after P. aeruginosa injection was marked by severe alteration of follicular definition with expansion of B-cell zone (hyperplasia) as well as tingible body macrophages containing degenerate cellular debris. Upper row images taken at 10x with expansion of boxed areas shown below. Size bars indicate 100 μm. Please see Supplemental Figure 1 for liver images from all groups. Data represents three independent experiments from male, female, C57BL/6, and Balb/cJ mice that were age, strain, and sex matched within each experiment (N = 4-5 mice per group, per experiment).