Platelet removal in the absence of infection does not affect the blood and SLO compartments. Mice were treated with PBS or 40 μg of anti-GPIIb antibody and killed 24 hours later. Blood, spleen, and peripheral lymphoid nodes (PLNs) were recovered and analyzed as described in “Methods.” (A) Flow plots of circulating immune cells in blood. Numbers indicate percentage of cells in each gate. (B) Number of immune cells in SLOs. Spleen and PLN cell populations after collagenase digestion, were counted, stained, and analyzed by flow cytometry. Open bars, PBS-treated controls; black bars, anti-GPIIb–treated mice. Error bars represent SEM. NS indicates nonsignificant. (C) Conserved splenic microarchitecture. Spleens were frozen in OCT medium, cut, and stained with antibodies to Thy1.2 (T cells, blue), B220 (B cells, green), and CD11c (DCs, red) or Moma-1 (metallophillic macrophages, blue), F4/80 (red pulp macrophages, green), and ER-TR9 (MZMs, red).