CTLA-4 blockade induces a microglia-Th1 cell partnership that stimulates microglia phagocytosis and anti-tumor function in glioblastoma

Immunity. 2023 Sep 12;56(9):2086-2104.e8. doi: 10.1016/j.immuni.2023.07.015. Epub 2023 Aug 11.


The limited efficacy of immunotherapies against glioblastoma underscores the urgency of better understanding immunity in the central nervous system. We found that treatment with αCTLA-4, but not αPD-1, prolonged survival in a mouse model of mesenchymal-like glioblastoma. This effect was lost upon the depletion of CD4+ T cells but not CD8+ T cells. αCTLA-4 treatment increased frequencies of intratumoral IFNγ-producing CD4+ T cells, and IFNγ blockade negated the therapeutic impact of αCTLA-4. The anti-tumor activity of CD4+ T cells did not require tumor-intrinsic MHC-II expression but rather required conventional dendritic cells as well as MHC-II expression on microglia. CD4+ T cells interacted directly with microglia, promoting IFNγ-dependent microglia activation and phagocytosis via the AXL/MER tyrosine kinase receptors, which were necessary for tumor suppression. Thus, αCTLA-4 blockade in mesenchymal-like glioblastoma promotes a CD4+ T cell-microglia circuit wherein IFNγ triggers microglia activation and phagocytosis and microglia in turn act as antigen-presenting cells fueling the CD4+ T cell response.

Keywords: AXL; CD4(+) T cell; CTLA-4; MER; MHC-II; glioblastoma; immunotherapy; microglia.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • CD4-Positive T-Lymphocytes
  • CD8-Positive T-Lymphocytes
  • CTLA-4 Antigen
  • Dendritic Cells
  • Glioblastoma* / drug therapy
  • Glioblastoma* / metabolism
  • Mice
  • Microglia
  • Phagocytosis
  • Th1 Cells


  • CTLA-4 Antigen