Supplementary Methods, Figures S1 - S9 from Access to Follicular Dendritic Cells Is a Pivotal Step in Murine Chronic Lymphocytic Leukemia B-cell Activation and Proliferation

Figure S1. Gating strategy to characterize and quantitate CD19+CD5+ leukemia Emu-Tcl1 cell frequencies and homeostatic chemokine receptor expression on splenic, LN, PB, and BM derived CD19+CD5+ gated Emu-Tcl1 tumor cells. This Figure complements Figure 1. Figure S2. Surface marker expression of murine Emu-Tcl1 leukemia cells is shown. Human primary B-CLL cells share characteristic expression of CXCR5. This Figure complements Figure 1. Figure S3. Enrichment plots of seven proliferation-related signatures are presented. Short term transfer of CXCR5+/+Emu-Tcl1 or CXCR5-/-Emu-Tcl1 tumor cells shows upregulation of the gene encoding the cell-cycle inhibitor p21 in CXCR5-deficient leukemia cells. Growth and activation delay of CXCR5-/- Emu-Tcl1 tumor cells can be reversed by direct contacts with stromal cells in vitro. This Figure complements Figure 2. Figure S4. (A) shows that CCR7-deficiency on leukemia cells does not affect their migratory behavior and complements Figure 3. (B) Ebi2-/-Emu-Tcl1 leukemia cells enter B cell follicles and the GC light zone area in a pattern comparable to Ebi2++Emu-Tcl1 leukemia cells, as presented in Figure 4, and (C) tumor growth of Ebi2-/-Emu-Tcl1 mice is unaltered compared to Wt Emu-Tcl1 mice. Figure S5. Human primary B-CLLs exhibit a characteristic FDC staining. This Figure complements Figure 4. Figure S6. Pertussis toxin (PTX) treatment induces apoptosis in Emu-Tcl leukemia cells co-cultured with FDC-HK stroma cells. This Figure complements Figure 4. Figure S7. Intravital application of anti-CD21/CD35 Fab fragments stains specifically GC light zone localized FDCs. These stainings complement Figure 5. Figure S8. Challenge of Rag2-/- mice with Emu-Tcl1 leukemia B cells induces FDC networks and a tumor cell-promoting cytokine and chemokine secretion. This Figure accompanies Figure 6. Figure S9. Abrogation of LTbetaR-signaling leads to disappearance of characteristic stromal elements within the B cell follicle; however, CD31+ blood vessels are not affected. In accordance with Figure 7, Ltalpha -/- Emu-Tcl1 mice exhibit substantially delayed leukemia growth and progression.