Under these conditions, the number of either TIM-3+ CD8+ T cells (Fig. 5a, Mann–Whitney test, *p < 0.05 vs D1-WT/hM3Dq) or LAG-3+ CD8+ T cells (Fig. 5d, Mann–Whitney test, *p < 0.05 vs D1-WT/hM3Dq) in the spleen was significantly decreased by repeated stimulation of D1-receptor-expressing neurons in the medial shell of the nucleus accumbens of tumor-bearing mice. Here, CD8A is linked to neoplasm.