Figure 1.

Decreased numbers of marginal zone B cells (MZB) and reduced MZB area in the spleen of FcμR^−/− mice. (A) Reduced proportion of the B220⁺CD21^highCD23^low MZB in FcμR^−/− mice. Left, representative FACS profiles; right, summary of eight pairs of WT and FcμR^−/− mice. (B) Absolute numbers of MZB (left) and total spleen cells (right). The results of eight pairs of mice are shown. (C) Spleen sections of WT and FcμR^−/− mice were stained for B220 (green) and mouse metallophilic macrophage (MOMA-1) (red). Scale bars, 100 µm. The proportion of MZB area was calculated by dividing the B220⁺ area outside the MOMA-1⁺ ring by the total B220⁺ area (n = 32; four MZB areas per section, four sections per mouse, two mice per group) using the Image J software. Representative staining results (left) and the mean MZB area (%) ± SD are shown. *p < 0.05; **p < 0.01.