Fig. 4. Lactate treatment increases stem-like CD8⁺ T cell population in MC38 tumors.

a Pseudotime trajectory of CD8⁺ T cells in tumors identifies the differentiation process and distinct states of CD8⁺ T cell subtypes. b Labeling of top marker genes on pseudotime trajectory identifies the cells in state 1 are stem-like T cells while those in state 7 are exhausted T cells. c Change of CD8⁺ T cell fraction with aPD1+Lac verses aPD1 treatment. R_O/E Lac analysis showed lactate treatment increased the T cell populations in states 1 and 7. d Validation of increase in TCF1⁺ PD1⁺ CD8⁺ T cell population after lactate treatment by flow cytometry. C57BL/6 mice (n = 8) were inoculated with 1 × 10⁶ MC38 tumor cells and treated with anti-PD-1 (10 mg/kg, day 14 and 17) and lactate (1.68 g/kg, s.c. daily from day 15 to 19). Tumors were harvested on day 20 and analyzed by flow cytometry. e, f Flow cytometry plot and quantification of TCF-1 expressions in tumor-infiltrating CD8⁺ T cells after different treatments. Samples are the same as described in D. Data are shown as means ± SEM. P value was determined by one-tail Chi-square test (c) or two-tail unpaired t-test (d, f). Source data are provided in Source Data file.