FIGURE 3. Membrane LT12 expression on B cells in peripheral lymphoid tissues and dependence on BLC.

a–f, Flow cytometric analysis of cells from wild-type (left) and LT^-/- (right) blood (a, b), spleen (c, d) and lymph nodes (LN; e, f) stained for LTR-Ig and B220. In f, lymph node cells were from irradiated wild-type mice that had been reconstituted for 8 weeks with LT ^-/- bone marrow. Gates with solid lines show LTR-Ig^hi B cells; total B cells were calculated as the cells in the region bounded by the dashed lines plus the cells within the LTR-Ig ^hi gate. Percentages of LTR-Ig^hi B cells as a fraction of total B cells are shown above the windows. g, Summarized data from several flow cytometric analyses as shown in a– f with additional data obtained from LT^-/- and HEL-specific Ig-transgenic mice. h, LT12 expression levels on B cells from blood, spleen and mesenteric lymph nodes (mLN) of BLC^-/- animals compared with B cells of BLC^+/- littermate controls. Cells were gated as in a–f. Bars represent the mean s.d. percentage of LTR-Ig^hi B cells for the indicated number of animals. Statistical comparison is by Student's t-test. i, Upregulation of LT12 on B cells migrating into spleen occurs in a PTX-sensitive manner. Each point represents an individual recipient and bars represent the mean percentages of LTR-Ig^hi B cells. j–m, LT12 upregulation on transferred B cells is dependent on BLC. Splenocyte donors and transfer recipients were as follows: Ly5.1⁺ wild type into BLC^+/- (j); Ly5.1 ⁺wild type into BLC^-/- (k); Ly9.1⁺ LT^-/- into Ly9.2⁺ wild type (l); Ly9.1⁺BLC^-/- into Ly9.2⁺ wild type (m). Data shown are LTR-Ig and B220 staining of transferred Ly5.1⁺ (j, k) or Ly9.1⁺ ( l, m) cells in recipient spleens 6 h after transfer, and are representative of 3 transfers of each type.