Fig. 3. Transduction of PDPN⁺ FSCs in the TME by intratumoral artLCMV-TRP2 application.

Mice were inoculated with B16F10-mCherry and immunized i.t. on day 7 with artLCMV-TRP2. a LCMV-NP RNA expression in tumor, tumor-draining, and non-draining lymph nodes (TDLN and NDLN) and spleen at indicated time points after i.t. artLCMV-TRP2 treatment. Dots indicate mean±s.e.m. for each time point. b, c Flow cytometric analysis with representative tSNE plot gated on viable Ter119⁻ cells on day 11. b Expression of indicated marker and c frequency of LCMV-NP⁺ cells among identified cell populations in the TME including: mCherry⁺ tumor cells, CD45⁺ immune cells, PDPN⁺ FSCs, and CD31⁺ BECs. Dots represent individual mice and lines indicate mean values ± s.e.m values. d Representative confocal microscopy of tumors on day 11 following i.t. artLCMV-TRP2 injection from n = 3 mice. Representative areas are shown: (i) in the center of the tumor and (ii) in the tumor margin. Arrows and arrowheads indicate artLCMV-transduced cells by positive staining for LCMV-NP. Scale bar 1000 μm (overview) and 10 μm (boxed areas). e–g Infection of FSCs from human skin and melanoma biopsies with artLCMV. Scale bar 50 μm. e Representative high resolution immunofluorescence images of artLCMV-transduced human skin-derived FSCs. f Frequency of LCMV-NP⁺ cells. g Frequency of CD90⁺ PDPN⁺ and CD90⁺ PDPN⁻ cells among LCMV-NP⁺ FSCs. Dots represent individuals and lines indicate mean values ± s.e.m values. Pooled data from two independent experiments with n = 11 mice (a) and n = 8 mice (c). Pooled data from n = 6 (PBMCs and Skin Fibroblasts) and n = 2 (Melanoma Fibroblasts) patients (f) and n = 7 patients (g). Statistical analysis was performed using two-way analysis of variance (ANOVA) with Bonferroni (a), one-way ANOVA with Tukey’s multiple comparison test (c), or unpaired two-tailed Student’s t test (f, g) with *P < 0.05: **P < 0.01; ***P < 0.001. Source data and exact P values are provided in the Source data file.