CD8(+) T 细胞中 TCR 诱导的 FOXP3 表达损害了它们的抗肿瘤活性

Adoptive cell transfer therapy using CD8 + T lymphocytes showed promising results eradicating metastatic malignancies.

However, several regulatory mechanisms limit its efficacy. We studied the role of the expression of the transcription factor FOXP3 on CD8 + T cell function and anti-tumor immunity.

Here we show that suboptimal T cell receptor stimulation of CD8 + T cells upregulates FOXP3 in vitro. Similarly, CD8 T cells transferred into tumor-bearing mice upregulate FOXP3 in vivo. Cell-intrinsic loss of FOXP3 by CD8 + T cells resulted in improved functionality after TCR stimulation and better antitumor responses in vivo.

Inhibition of the FOXP3/NFAT interaction likewise improved CD8 + T cell functionality. Transcriptomic analysis of cells after TCR stimulation revealed an enrichment of genes implicated in the response to IFN-γ, IFN-α, inflammatory response, IL-6/JAK/STAT, G2M checkpoint and IL-2/STAT signaling in FOXP3-deficient CD8 + T cells with respect to FOXP3-wt CD8 + T cells.

Our results suggest that transient expression of FOXP3 by CD8 + T cells in the tumor microenvironment restrains their anti-tumor activity, with clear implications for improving T cell responses during immunotherapy.