Fig. 3. Pentanoate enhances anti-tumor activity of antigen-specific CTLs.

a Experimental design for the role of SCFAs in promoting anti-tumor immunity. b–g After three days of pretreatment with indicated HDAC inhibitors, CD8⁺CD45.1⁺ OVA-specific CTLs were transferred intraperitoneally (i.p.) into CD45.2⁺ mice bearing 5-days old B16OVA tumors. Tumor volume (b) and tumor mass (c) were analyzed on day 14 after inoculation of tumor cells (n = 6 mice/group combined from two independent experiments). The t-SNE plots in (d) show CD8⁺CD45.1⁺ cells among lymphocytes from the tumor-draining LNs. The percentage (e) and total cell number (f) of transferred CD8⁺CD45.1⁺ OT-I CTLs in the tumor-draining LNs at day 14 after tumor inoculation are shown. In g the total cell numbers of transferred antigen-specific IFN-γ⁺TNF-α⁺ CTLs were examined on day 14 after inoculation of B16OVA tumors in tumor-draining LNs (in e–g, n = 6 mice/group combined from two independent experiments). h–j OVA-specific CD45.1⁺ CTLs pretreated with pentanoate were adoptively transferred into CD45.2⁺ mice bearing 5-days old PancOVA tumors. Tumor volume (h) and tumor weight (i) were determined on day 23 post tumor inoculation. In j frequencies of transferred IFN-γ-producing CD8⁺ T cells in draining LNs and spleens were analyzed on day 23 post tumor inoculation (n = 6 mice/group combined from two independent experiments). Multiple group comparison (b, h) was performed by a linear-mixed effects model with Tukey correction. The two-tailed unpaired Student’s t-test was applied to compare two groups (n.s. = not significant; results are shown as mean ± s.e.m). Source data are provided as a Source data file.