Fig. 2: Intravascular leukocytes recruited to OV-infected tumors interact with OV administered during a second dose.

a–h Intravital imaging of CT26^LacZ tumor microenvironment after initial (a–d) or second dose (e–h) of VSV-AF647. Virus (blue, arrows) delivered as a first dose interacts with tumor cells (a), endothelium (b), neutrophils (c), and other leukocytes (d). Virus delivered as a second dose is mainly captured by monocytes defined as CD11b⁺Ly6G^- cells (e), expressing Ly6C (f), CD169 (g), and F4/80 (h). Vessels counterstained with FITC-BSA (gray) and delineated by white dashed lines. Scale bar, 25 µm. i Quantification of VSV microdistribution in tumor microenvironment after single or repeated VSV administration. Results are shown as percentage of total VSV-bound cells and plotted as mean ± SEM (n = 7; two-way ANOVA followed by Sidak’s multiple comparisons test). j FC analysis of intravascular leukocytes in tumor samples at the time of first or second VSV treatment. Intravascular fraction of leukocytes is identified by anti-CD45 injected into the tail vein 10 minutes before tissue collection. Results are shown as percentage of intravascular cells and plotted as mean ± SEM (n = 4; unpaired t-test). k FC analysis of blood samples collected from untreated mice or 48 h post VSV i.v. injection (10⁶ PFU). Results are shown as percentage of CD45 + cells and plotted as mean ± SEM (n = 4; unpaired t-test). l FC analysis of select leukocyte populations in CT26^LacZ tumor at the time of first or second VSV treatment (see also Supplementary Fig. 2e). Results are shown as percentage of CD45 + cells and plotted as mean ± SEM (unpaired t-test).