STAT5 激活通过阻止 PD-1 抑制增强过继疗法联合肽疫苗接种的疗效

Adoptive cell therapy (ACT) using retrovirally transduced T cells represents a promising strategy for enhancing antitumor responses. When used with TriVax, a peptide vaccination strategy, this approach synergistically expands antigen-specific cell populations. STAT5 plays a vital role as a transcription factor in regulating T-cell proliferation and their differentiation into effector and memory T cells.

We aimed to explore the combination therapy using CD8 T cells engineered to express constitutively active STAT5 (CA-STAT5) with vaccines. CD8 T cells were transduced with a retrovirus (RV) encoding the mouse gp100 T-cell receptor (TCR). In certain treatment groups, cells were also co-transduced with RV encoding CA-STAT5.

We assessed transduction efficiency and functional activity through flow cytometry and various functional assays. B16F10 tumor-bearing mice were treated with ACT using RV-transduced CD8 T cells and subsequently vaccinated with TriVax.

We demonstrate that TriVax selectively enhanced the expansion of ACT cell populations bearing gp100-specific TCRs. T cells engineered to express CA-STAT5 showed not only increased expansion and polyfunctionality but also reduced PD-1 expression, leading to decreased cellular exhaustion. In a B16F10 melanoma mouse model, our approach yielded a potent antitumor effect, with CA-STAT5 further amplifying this response.

We found that CA-STAT5 improved antitumor activities, in part, by attenuating the PD-1/PD-L1 inhibitory pathway.

These findings indicate that TCR-transduced CD8 T cells can undergo antigen-dependent expansion when exposed to TriVax.

Additionally, the expression of CA-STAT5 enhances T-cell proliferation and persistence, partly by promoting resistance to PD-1/PD-L1-mediated inhibition in antitumor T cells.