Figure 2.

Chronic LCMV infection induces transient remodeling of BM vascular and ECM networks and persistent destruction of CARc infrastructure. (A) Maximum-intensity projection of confocal image stacks from representative femoral regions of uninfected controls (ctrl), 7-, or 56-dpi Cxcl12-GFP transgenic mice. Segmented signal of sinusoidal vessels stained for CD105 is shown in the middle panel; green, CXCL12-GFP⁺ CARc; lower panel, tissue maps of CARc densities. Scale bars for all panels, 200 µm. (B) Zoomed-in images from regions demarcated with white dotted rectangles in low-magnification images in A. The CXCL12-GFP signal is shown in green, and collagen IV–specific signal is shown in red (ECM fibers). (C) Quantification of the fraction of intrasinusoidal volumes (vol) from total BM tissue using segmentation of sinusoidal lumina (n = 4–7 femurs from at least three independent experiments). (D) CARc densities measured by 3D QM at indicated time points after infection (n = 4–9 femurs from at least three independent experiments). (E) Quantification of CARc densities by 3D QM at late time points after infections (n = 4 mice, one long-term infection experiment). (F and G) FC analysis of apoptosis (apop) of CARc, staining with DAPI and anti-annexin V. Representative dot plots (F) and quantification (G) of viable (DAPI⁻annexin V⁻), early apoptotic (DAPI⁻annexin V⁺), and dead (DAPI⁺) fractions after infection with LCMV-cl13 (n = 4 mice from one representative of two independent experiments). (H and I) Cleaved caspase-3 staining of CARcs; histograms (H) and quantification (I) of positive CARc fractions (n = 4 mice, one representative of two experiments). Statistical significance was analyzed using two-tailed t test. *, P < 0.05; **, P < 0.01; ***, P < 0.001.