Human CD8 + CD28 - T suppressor cells expanded by common gamma chain (γc) cytokines retain steady allospecific suppressive capacity in vivo

BMC Immunol. 2020 Apr 29;21(1):23. doi: 10.1186/s12865-020-00354-z.


Background: CD8+CD28- T suppressor (Ts) cells play critical role in transplant tolerance. Our previous study has generated CD8+CD28- Ts cells in vitro which exert robust allospecific suppressive capacity in vitro.

Results: CD8+CD28- Ts cells were expanded by stimulating human CD8+ T cells with allogeneic antigen presenting cells in the presence of the common gamma chain cytokines IL-2, IL-7 and IL-15 in vitro, and were further verified in vitro through day 7 to 11 for their persistency of the allospecific suppressive capacity. When CD8+CD28- Ts cells were adoptively transferred into NOG mice, their capacity to inhibit CD4+ T cell proliferation in allospecific manner remained potent on 11 days after their injection. The mechanisms for expansion of CD8+CD28- Ts cells by the common gamma chain cytokines were investigated. These included promoting CD8+CD28- T cells proliferation, converting CD8+CD28+ T cells to CD8+CD28- T cells and decreasing CD8+CD28- T cell death. Furthermore, the expanded CD8+CD28- Ts cells showed upregulation of the co-inhibitory molecule Tim-3 and down-regulation of the cytotoxic molecule granzyme B.

Conclusions: In summary, these results demonstrated that the in vitro-expanded human CD8+CD28- T cells retained potent allospecific suppressive capacity in vivo and depicted multiple mechanisms for the expansion of Ts cells, which might promote further bench to clinic research.

Keywords: Alloantigen specific tolerance; CD8+CD28− T suppressor cells; Common gamma chain cytokines; Transplant tolerance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigen-Presenting Cells / immunology
  • CD28 Antigens / immunology*
  • CD8-Positive T-Lymphocytes / immunology*
  • Cell Death / immunology
  • Cell Proliferation / physiology
  • Cytokines / immunology*
  • Down-Regulation / immunology
  • Female
  • Granzymes / immunology
  • Humans
  • Mice
  • Up-Regulation / immunology


  • CD28 Antigens
  • Cytokines
  • Granzymes