Fig. 5 ∣. Impaired blood vessel function in metastatic lesions.

a, Doppler OCT image of a metastatic LN on days 1, 3, 5 and 8 after primary tumour (4T1) resection. The depth is denoted by colour: yellow/green (superficial); red (deep). OCT detects vessels up to approximately 1 mm. The dashed lines indicate the margin of the LN lesion. Scale bar, 500 μm. The experiment is representative of four biological replicates. b, Quantification of vessels per 5 × 10⁵ μm² in individual non-metastatic (TDLN, n = 5) and metastatic (MET, n = 4) LNs from longitudinal imaging by OCT. c, Quantification of OCT vessel diameter from metastatic and non-metastatic LNs. The experiment is representative of four biological replicates. d, Adoptive transfer of CMFDA-labelled (green) naive T cells into naive or 4T1 tumour-bearing mice 14 d after primary tumour resection (PNAd⁺ HEVs; red) and cancer cells (cytokeratin⁺, blue). Scale bar, 636 μm. e,f, Quantification of adoptively transferred T cells entering naive LNs (N, n = 8), contralateral LNs (CLN, n = 9), MET LNs (MET, n = 5) (e), and within the non-tumour area (NT) and tumour area (T) of MET LNs (n = 5) within 4 h of cell transfer (f). g,h, The number of adoptively transferred T cells associated with HEVs outside (g) and inside (h) metastatic lesions, according to the distance from the edge of the lesion. n = 3. For b, statistical analysis was performed using a mixed regression model in which vessel density was the dependent variable identified by individual animals, with the experimental group (non-metastatic TDLN versus metastatic TDLN), time (continuous) and an interaction term between time and group as fixed effects, to show a difference between vessel density in non-metastatic and metastatic TDLNs. For c and e–h, significance was tested using two-tailed paired Student’s t-tests (f–h) and one-way ANOVA with Tukey’s honestly significant difference post hoc test (c and e). For e and f, data are mean ± s.e.m.