T cells conditioned with MDSC show an increased anti-tumor activity after adoptive T cell based immunotherapy

Patrick L. Raber, Rosa A. Sierra, Paul T. Thevenot, Zhang Shuzhong, Dorota D. Wyczechowska, Takumi Kumai, Esteban Celis, Paulo C. Rodriguez

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


The success of adoptive T cell-based immunotherapy (ACT) in cancer is limited in part by the accumulation of myeloid-derived suppressor cells (MDSC), which block several T cell functions, including T cell proliferation and the expression of various cytotoxic mediators. Paradoxically, the inhibition of CD8+ T cell differentiation into cytotoxic populations increased their efficacy after ACT into tumor-bearing hosts. Therefore, we aimed to test the impact of conditioning CD8+ T cells with MDSC on their differentiation potential and ACT efficacy. Our results indicate that MDSC impaired the progression of CD8+ T cells into effector populations, without altering their activation status, production of IL-2, or signaling through the T cell receptor. In addition, culture of CD8+ T cells with MDSC resulted in an increased ACT anti-tumor efficacy, which correlated with a higher frequency of the transferred T cells and elevated IFNγ production. Interestingly, activated CD62L+ CD8+ T cells were responsible for the enhanced anti-tumor activity showed by MDSC-exposed T cells. Additional results showed a decreased protein synthesis rate and lower activity of the mammalian/ mechanistic target of rapamycin (mTOR) in T cells conditioned with MDSC. Silencing of the negative mTOR regulator tuberous sclerosis complex-2 in T cells co-cultured with MDSC restored mTOR activity, but resulted in T cell apoptosis. These results indicate that conditioning of T cells with MDSC induces stress survival pathways mediated by a blunted mTOR signaling, which regulated T cell differentiation and ACT efficacy. Continuation of this research will enable the development of better strategies to increase ACT responses in cancer.

Original languageEnglish (US)
Pages (from-to)17565-17578
Number of pages14
Issue number14
StatePublished - 2016
Externally publishedYes


  • Adoptive T cell transfer immunotherapy (ACT)
  • Central memory T cells (T)
  • Immune response
  • Immunity
  • Immunology and Microbiology Section
  • Mammalian target of rapamycin (mTOR)
  • Myeloid-derived suppressor cells (MDSC)
  • Stem cell memory T cells (T)

ASJC Scopus subject areas

  • Oncology


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