Figure 7.

Integrin VLA-4 mediates retention of Cxcr5^−/−Eμ-Tcl1 leukemia cells in the splenic MZ. (A) Cxcr5^−/−Eμ-Tcl1 cells (1 × 10⁷) were transferred in wt recipients (n = 4). 22 h later, mice were treated with an anti-CD49d Ab. After 3 h, the fraction of transferred cells in splenic MZ and RP was counted (for each spleen four different layers with 3 pictures/layer were counted). MZ was defined immunohistologically as outside of the MOMA-1⁺ ring and B220⁺. Mean ± SEM are depicted. p values were calculated with the Mann-Whitney U test. (B–D) 1 × 10⁶ Eμ-Tcl1 cells were transferred i.v. in wt recipients treated with an IgG control, or inhibitory Abs against CXCL13, CD49d, or both (n = 3–5 mice/group and experiment) twice per week for 3 weeks from day 4 on. (C) Representative splenic sections were stained for TCL (red), B220 (B cells, blue), MOMA-1 (MMMs, green), and CD35 (FDCs, white). Scale bar, 100 μm. (D) Tumor progression was analyzed 24 d after transfer. Mean ± SEM of one representative out of three independent experiments are shown. p values calculated with the Student's t test are depicted.