Phenotype and morphology of iMacs in the spleen and bone marrow of immunocompromised mice.

(A) Splenocytes from mice bearing a large (more than 1 cm²) subcutaneous TS/A tumor were stained with FITC–anti-Gr-1 and PE–anti-CD11b antibodies, and were sorted by FACS into double-positive or -negative cells. Cells were spun onto slides and stained with May-Grünwald-Giemsa (MGG). Magnification, × 260. (B) Splenocytes from the same mice bearing TS/A tumor, or immunized 6 days earlier with 5 × 10⁶ PFU of IL-2-rVV (VV) were stained with anti-CD11b, and one of the markers indicated. After gating CD11b⁺ cells, the cytometric profile for each marker was plotted (histograms to the right of the arrows). Numbers indicate the percentage of positive cells. Isotype-matched mAb were used as control for background staining (shaded areas). The percentage of CD11b⁺ cells in spleens of normal mice was lower than 4%, with a percentage of CD11b⁺/Gr-1⁺ cells around 0.5% to 1% (not shown). (C) CD11b and CD31 expression in the red-cell depleted, unseparated bone marrow cells of normal, tumor-bearing, and VV-immunized mice was assessed by 2-color cytometry. The plots shown in this figure are representative of 3 different experiments.