Fig. 3. Genetic ablation of nociceptors safeguards anti-tumour immunity.
a, Orthotopic B16F10-mCherry-OVA cells (2 × 105 cells, i.d.) were injected into the left hindpaw of wild-type mice. As measured on day 13 after tumour inoculation, intratumoral CD8+ T cell exhaustion positively correlated with thermal hypersensitivity (R2 = 0.55, P ≤ 0.0001). The thermal pain hypersensitivity represents the withdrawal latency ratio of the ipsilateral paw (tumour-inoculated) to the contralateral paw. b, Orthotopic B16F10-mCherry-OVA (5 × 105 cells, i.d.) were inoculated into the flank of eight-week-old male and female mice with sensory neurons intact (Trpv1WT::DTAfl/WT) or ablated (Trpv1cre::DTAfl/WT). The median length of survival was increased by around 250% in nociceptor-ablated mice (measured until 22 days after inoculation). c–f, Sixteen days after tumour inoculation, sensory-neuron-ablated mice have reduced tumour growth (c) and increased tumour infiltration of IFNγ+ CD8+ T cells (d), and the proportion of PD-1+LAG3+TIM3+ CD8+ T cells is decreased (e). This reduction in B16F10-mCherry-OVA (5 × 105 cells, i.d.) tumour volume was absent in nociceptor-ablated mice whose CD8+ T cells were systemically depleted (f; assessed until day 14; anti-CD8, 200 μg per mouse, i.p., every 3 days). g,h, To chemically deplete their nociceptor neurons, Rag1−/− mice were injected with RTX. Twenty-eight days later, the mice were inoculated with B16F10-mCherry-OVA (5 × 105 cells, i.d.). RTX-injected mice that were adoptively transferred with naive OVA-specific CD8+ T cells (i.v., 1 × 106 cells, when tumour reached around 500 mm3) showed reduced tumour growth (g; assessed until day 19) and exhaustion (h) compared to vehicle-exposed Rag1−/− mice. Data are shown as a linear regression analysis ± s.e. (a), as a Mantel–Cox regression (b), as mean ± s.e.m. (c,f,g) or as box-and-whisker plots (as defined in Fig. 1b,c), for which individual data points are given (d,e,h). n as follows: a: n = 60; b: intact (n = 62), ablated (n = 73); c: intact (n = 20), ablated (n = 25); d: intact (n = 24), ablated (n = 23); e: intact (n = 23), ablated (n = 26); f: intact + anti-CD8 (n = 10), ablated + anti-CD8 (n = 8); g: vehicle (n = 12), RTX (n = 10); h: vehicle (n = 11), RTX (n = 10). Experiments were independently repeated two (a,f–h) or six (b–e) times with similar results. P values were determined by simple linear regression analysis (a), Mantel–Cox regression (b), two-way ANOVA with post-hoc Bonferroni (c,f,g) or two-sided unpaired Student’s t-test (d,e,h).